Patent Publication Number: US-2021190410-A1

Title: Condensation management apparatus with gutter assembly

Description:
TECHNICAL FIELD 
     This application relates generally to fluid control films and methods for managing condensation. 
     BACKGROUND 
     Water condensation can be problematic in the operation of manufacturing and processing plants. Approximately 70 percent of food production in the United States passes through or is dependent on a cold chain, where food product or ingredients are refrigerated or frozen using a refrigeration system. A conveyor system is typically used to transport product into and out of the refrigeration system. Cooled surfaces near the entrance and exit of the refrigeration system produce condensation, which can drip onto the product if not properly managed. This condensation poses both a food quality and food safety risk. Persistent moisture can lead to the proliferation of microorganisms. The presence of microorganisms in product can decrease shelf life or cause foodborne illness. Excess moisture in certain dry products, for example bread, creates a quality issue where condensate droplets contact the product. For these reasons, it is desirable to prevent condensation formed above the entrance and exit of a refrigeration system from contacting product transported by a conveyor system. 
     Current mitigation solutions include manual and mechanical interventions to prevent condensation that is continuously formed above the entrance and exit of a refrigeration system from contacting product on the conveyor system. Manual approaches entail monitoring condensation build-up above the entrance and exit and periodically removing accumulated condensation by wiping or drying the surface. Because of the risk of releasing condensation during wiping or drying, production must be stopped while this procedure is being performed, leading to a loss in productivity. 
     An example of a current mechanical solution involves installation of air curtains above the entrance and exit of a refrigeration system. The air curtains are designed to minimize mixing of room air with internal air of the cooled chamber. Air curtains incur additional expense and expertise to both install and operate. The high velocity of air required may also disturb or alter product moving through the air curtain. A simpler mechanical intervention involves installation of a sliding panel at the front of the opening to minimize the area of the gap where air exchange occurs. The panel height is adjusted to be slightly above the height of the incoming product. While this can reduce the volume of air mixing at the opening, cold air contacts the back side of the sliding panel causing condensation to form on both the front and back sides and in the niches formed where the sliding panel is affixed. These niches are difficult to access and require frequent disassembly to ensure adequate cleaning and sanitation of the surfaces. 
     SUMMARY 
     Embodiments directed to a condensation management apparatus comprising an adhesive-backed microstructured film that facilitates the transfer of condensate along pre-defined channels and into a gutter-type assembly, which collects the condensate and further moves it to a collection area such as a drain or further tube. The microstructured film includes parallel channels, or grooves, which in some embodiments are designed to wick water along the channels. 
     A first set of embodiments is directed to using the aforementioned apparatus to collect condensation on a vertical surface of a component subject to condensation build-up, for example in various types of food processing operations. A second set of embodiments is directed to using the apparatus to collect condensation from a horizontal surface of the component. In some cases, the horizontal surface may have protuberances, and given correct sizing of a terminal flange, it is possible to successfully manage condensate even when the surface is not perfectly flat, relying on the capillary movement of water though the channels. Finally, a set of embodiments is directed to collecting condensation on a component having both vertical and horizontal surfaces. 
     The above summary is not intended to describe each disclosed embodiment or every implementation of the present disclosure. The figures and the detailed description below more particularly exemplify illustrative embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  illustrates a plan view of a fluid control film according to an example embodiment; 
         FIG. 1B  illustrates a cross section of a fluid control film according to an example embodiment; 
         FIGS. 2A and 2B  illustrate a cross section of a fluid control film with primary and secondary channels according to an example embodiment; 
         FIG. 2C  illustrates a cross section of a fluid control film with primary and secondary channels disposed on opposing major surfaces of the fluid control film according to an example embodiment; 
         FIG. 3  illustrates a cross section of a fluid control film with ridges and channels according to an example embodiment; 
         FIG. 4  illustrates a typical refrigeration system comprising a cooled chamber and a conveyor system to which a condensation management apparatus can be attached in accordance with various embodiments; 
         FIG. 5  illustrates a condensation management apparatus attached to a component of a refrigeration system in accordance with various embodiments; 
         FIGS. 6A-6C  illustrate the impact of the slope of a microstructured fluid control film on the transport of condensate by capillary action across the film in accordance with various embodiments; 
         FIG. 7  illustrates a condensation management apparatus attached to a component of a refrigeration system in accordance with various embodiments; 
         FIG. 8  illustrates a condensation management apparatus attached to a component of a refrigeration system in accordance with various embodiments; 
         FIG. 9  illustrates a cooling apparatus that simulates the entrance or exit of a standard food industry freezer tunnel; 
         FIG. 10  illustrates a condensation management apparatus attached to the cooling apparatus illustrated in  FIG. 9  in accordance with various embodiments; 
         FIG. 11  illustrates a condensation management apparatus attached to an experimental cooling apparatus in accordance with various embodiments; 
         FIG. 12  is a graph of collected condensate as a function of time for an experiment conducted using the apparatus illustrated in  FIG. 11 ; 
         FIG. 13  is a photograph of a terminal end of the condensation management apparatus attached to the apparatus illustrated in  FIG. 11 ; 
         FIG. 14  illustrates a condensation management apparatus attached to a component of a refrigeration system in accordance with various embodiments; 
         FIG. 15A  is a front view of a condensation management apparatus attached to a cooling apparatus in accordance with various embodiments; 
         FIG. 15B  is a perspective view of the condensation management apparatus and cooling apparatus illustrated in  FIG. 15A ; 
         FIG. 15C  illustrates longitudinal openings of fluid control film channels within a condensate collection region of the film oriented towards a direction of gravity in accordance with various embodiments; 
         FIG. 15D  illustrates a channel longitudinal axis of fluid control film channels within a siphon region of the film tilted at a tilt angle with respect to an axis normal to the direction of gravity; 
         FIG. 16A  is a front view of a condensation management apparatus attached to a cooling apparatus in accordance with various embodiments; 
         FIG. 16B  is a perspective view of the condensation management apparatus and cooling apparatus illustrated in  FIG. 15A ; 
         FIG. 17A  illustrates a condensation management apparatus attached to an experimental cooling apparatus in accordance with various embodiments; 
         FIG. 17B  is a graph of collected condensate as a function of time for an experiment conducted using the apparatus illustrated in  FIG. 17 ; and 
         FIG. 17C  illustrates a condensation management apparatus attached to an experimental cooling apparatus in accordance with various embodiments. 
         FIG. 18  is an apparatus having a gutter assembly attached to a vertical surface thereof, with the use of a microstructured, adhesive-backed film. 
         FIG. 19  is a side view of an apparatus similar to that shown in  FIG. 18 , but with the gutter assembly coupled in an alternative location. 
         FIG. 20  is an apparatus having a gutter assembly attached to a horizontal surface thereof with the use of a microstructured, adhesive-backed film. 
         FIG. 21  is a side view of the apparatus of  FIG. 20 . 
         FIG. 22  is a further side view of the apparatus of  FIG. 20 . 
         FIG. 23  is a side view of a further apparatus. 
         FIG. 24  is an apparatus having a gutter assembly attached to both the horizontal and vertical surfaces thereof with lengths of microstructured, adhesive-backed film. 
         FIG. 25  is a profile view of an alternative gutter assembly. 
     
    
    
     The figures are not necessarily to scale. Like numbers used in the figures refer to like components. However, it will be understood that the use of a number to refer to a component in a given figure is not intended to limit the component in another figure labeled with the same number. 
     DETAILED DESCRIPTION 
     Embodiments discussed herein involve a condensation management apparatus comprising a fluid control film arrangement that transports condensate along microcapillary channels away from underlying sensitive locations to a designated release location. In some embodiments, a condensation management apparatus comprising a fluid control film arrangement manages condensation produced on a vertical component by transporting condensate laterally along microcapillary channels to a designated release location at an end of the film arrangement. In other embodiments, a condensation management apparatus comprising a fluid control film arrangement manages condensation produced on the underside of a horizontal component by transporting condensate laterally along microcapillary channels to a designated release location at an end of the film arrangement. 
       FIG. 1A  illustrates an elongated fluid control film with flow channels (microchannels) that are parallel with respect to a longitudinal axis of the fluid control film, the x-axis in  FIG. 1A . Fluid control film  100  includes an array of channels  130  that extend across a length of the film  100 . The channels  130  have a channel longitudinal axis  131  that is parallel with a longitudinal axis  101  of the film  100 . Ridges  120  rise above the surface of the film  100  along the z-axis to form the channels  130 , with each channel  130  having a ridge  120  on either side running along the channel longitudinal axis  131 . In some embodiments, each set of adjacent ridges  120  are equally spaced apart. In other embodiments, the spacing of the adjacent ridges  120  may be at least two different distances apart. 
     The channels  130  are configured to provide capillary movement of fluid in the channels  130  and across the film  100 . The capillary action wicks the fluid to disperse it across the film  100  so as to increase the surface to volume ratio of the fluid and enable more rapid transport of the fluid. The channels  130  have openings  140  at opposing first and second edges  102  and  104  of the film  100 . The openings  140  provide fluid release locations of the film  100 . Fluid that collects within the channels  130  can be wicked to the first and second edges  102  and  104  and released from the film  100  at the openings  140 . In some embodiments, the film  100  can be oriented so that fluid that collects within the channels  130  is predominately released from the film  100  by openings  140  at either the first edge  102  or the second edge  104 . 
       FIG. 1B  illustrates a cross section of the film  100 . The channels  130  of the film  100  are defined by first and second ridges  120  disposed on either side of the channel  130 . As shown in  FIG. 1B , the ridges  120  can extend along the z-axis, generally normal to a bottom surface  130   a  of the channel  130 . Alternatively, in some embodiments, the ridges  120  can extend at a non-perpendicular angle with respect to the bottom surface  130   a  of the channel  130 . The first and second primary ridges  120  have a height h p  that is measured from the bottom surface  130   a  of the channel  130  to a top surface  120   a  of the ridges  120 . The ridge height h p  may be selected to provide durability and protection to the film  100 . In some embodiments, the ridge height h p  is about 25 μm to about 500 μm, the cross sectional channel width, w c , is about 25 μm to about 500 μm, and the cross sectional ridge width, w r , is about 30 μm to about 250 μm. 
     In some embodiments, as shown in  FIG. 1B , the side surfaces  120   b  of the channels  130  may be sloped in cross section so that the width of the ridge  120  at the bottom surface  130   a  of the channel  130  is greater than the width of the ridge  120  at the top surface  120   a  of the ridges  120 . In this scenario, the width of the channel  130  at the bottom surface  130   a  of the channel  130  is less than the width of the channel  130  at the top surface  120   a  of the ridges  120 . Alternatively, the side surfaces of the channels  130  can be sloped so that the channel width at the bottom surface  130   a  of the channel  130  is greater than the channel width at the top surface  120   a  of the ridges  120 . 
     The film  100  has a thickness t v  measured from a bottom surface  110   a  of the film  100  to the bottom surface  130   a  of the channel  130 . The thickness t v  can be selected to allow liquid droplets to be wicked into the film  100  but still maintain a robust structure. In some embodiments, the film thickness t v  is less than about 75 μm thick, or between about 20 μm to about 200 μm. A hydrophilic coating  150  may be disposed, e.g., plasma deposited, on the microstructured surface of the film  100 . 
       FIGS. 2A and 2B  are cross sections of a fluid control device  200  according to an example embodiment. The fluid control device  200  illustrated in  FIG. 2A  includes a fluid control film  201 , an optional adhesive layer  205 , and an optional release layer  206  disposed on the surface of the adhesive layer  205  opposite the film  201 . The release layer  206  may be included to protect the adhesive layer  205  prior to the application of the adhesive layer  205  to an external surface  202 . For example, the external surface  202  may be an external surface of a component of a system that condenses water vapor.  FIG. 2B  shows the fluid control device  200  installed on the external surface  202  with the release layer  206  removed. 
     The fluid control device  200  comprises a fluid control film  201  having primary and secondary channels  230 ,  231  defined by primary and secondary ridges  220 ,  221 , wherein the channels  230 ,  231  and ridges  220 ,  221  run along a longitudinal axis of the film  201 , e.g., the x-axis as previously discussed in connection with  FIG. 1A . Each primary channel  230  is defined by a set of primary ridges  220  (first and second) on either side of the primary channel  230 . The primary ridges  220  have a height h p  that is measured from a bottom surface  230   a  of the channel  230  to the top surface  220   a  of the ridges  220 . 
     In some embodiments, microstructures are disposed within the primary channels  230 . In some embodiments, the microstructures comprise secondary channels  231  disposed between the first and secondary primary ridges  220  of the primary channels  230 . Each of the secondary channels  231  is associated with at least one secondary ridge  221 . The secondary channels  231  may be located between a set of secondary ridges  221  or between a secondary ridge  221  and a primary ridge  220 . 
     The center-to-center distance between the primary ridges  220 , d pr , may be in a range of about 25 μm to about 500 μm; the center-to-center distance between a primary ridge  220  and the closest secondary ridge  221 , d ps , may be in a range of about 5 μm to about 350 μm; the center-to-center distance between two secondary ridges  221 , d ss , may be in a range of about 5μm to about 350 μm. In some cases, the primary ridges  220  and/or secondary ridges  221  may taper with distance from their bases  222 ,  233 . The distance between external surfaces of a primary ridge  220  at the base  222 , d pb , may be in a range of about 15 μm to about 250 μm and may taper to a smaller distance of d pt  in a range of about 1 μm to about 25 μm. The distance between external surfaces of a secondary ridge  221  at the base  233 , d sb , may be in a range of about 15 μm to about 250 μm and may taper to a smaller distance of d st  in a range of about 1 μm to about 25 μm. In one example, d pp =0.00898 inches, d ps =0.00264 inches, dss=0.00185 inches, d pb =0.00251 inches, d pt =0.00100 inches, d sb =0.00131 inches, dst=0.00100 inches, h p =0.00784 inches, and h s =0.00160 inches. 
     The secondary ridges  221  have height h s  that is measured from the bottom surface  230   a  of the channel  230  to a top surface  221   a  of the secondary ridges  221 . The height h p  of the primary ridges  220  may be greater than the height h s  of the secondary ridges  221 . In some embodiments, the height h p  of the primary ridges is between about 25 μm to about 500 μm and the height of the secondary ridges h s  is between about 5μm to about 350 μm. In some embodiments, a ratio of the secondary ridge  221  height h s  to the primary ridge  220  height h p  is about 1:5. The primary ridges  220  can be designed to provide durability to the film  200  as well as protection to the secondary channels  231 , secondary ridges  221  and/or or other microstructures disposed between the primary ridges  220 . 
     The fluid control device  200  may also have an adhesive layer  205  disposed on the bottom surface  201   a  of the fluid control film  201 . The adhesive layer  205  may allow the fluid control film  200  to be attached to an external surface  202  to help manage liquid dispersion across the external surface. The adhesive layer  205  has a thickness t a  and the film  201  has a thickness t v  from the bottom surface  230   a  of the channels  230 ,  231  to the bottom surface  201   a  of the film  201 . In some embodiments, the total thickness between the bottom surface  230   a  of the channels  230 ,  231  and the bottom surface  205   a  of the adhesive layer  205 , t v +t a  can be less than about 300 μm, e.g., about 225 μm. The combination of the adhesive layer  205  and the film  201  forms a fluid control tape. The adhesive layer  205  may be continuous or discontinuous. The tape  200  may be made with a variety of additives that, for example, make the tape suitable for wicking various liquids including neutral, acidic, basic and/or oily materials. The tape  200  is configured to disperse fluid across the surface of the film  201  to facilitate transport of the fluid to end openings of the film  201 . 
       FIG. 2C  illustrates a cross-section of a fluid control film with primary and secondary channels disposed on opposing major surfaces of the fluid control film according to an example embodiment. The fluid control film  250  illustrated in  FIG. 2C  includes a first major surface  203  and an opposing second major surface  204 . The first major surface  203  includes primary and secondary channels  230 ,  231  defined by primary and secondary ridges  220 ,  221 , wherein the channels  230 ,  231  and ridges  220 ,  221  run along a longitudinal axis of the film  250 , e.g., the x-axis as previously discussed in connection with  FIG. 1A . Each primary channel  230  is defined by a set of primary ridges  220  (first and second) on either side of the primary channel  230  The primary ridges  220  have a height h p  that is measured from a bottom surface  230   a  of the channel  230  to the top surface  220   a  of the ridges  220 . 
     In some embodiments, microstructures are disposed within the primary channels  230 . In some embodiments, the microstructures comprise secondary channels  231  disposed between the first and secondary primary ridges  220  of the primary channels  230 . Each of the secondary channels  231  is associated with at least one secondary ridge  221 . The secondary channels  231  may be located between a set of secondary ridges  221  or between a secondary ridge  221  and a primary ridge  220 . 
     The second major surface  204  includes primary and secondary channels  270 ,  271  defined by primary and secondary ridges  260 ,  261 , wherein the channels  270 ,  271  and ridges  260 ,  261  run along a longitudinal axis of the film  250 , e.g., the x-axis. Each primary channel  270  is defined by a set of primary ridges  260  (first and second) on either side of the primary channel  270 . The primary ridges  260  have a height h p  that is measured from a bottom surface  270   a  of the channel  270  to the top surface  260   a  of the ridges  260 . 
     In some embodiments, microstructures are disposed within the primary channels  270 . In some embodiments, the microstructures comprise secondary channels  271  disposed between the first and secondary primary ridges  260  of the primary channels  270 . Each of the secondary channels  271  is associated with at least one secondary ridge  261 . The secondary channels  271  may be located between a set of secondary ridges  261  or between a secondary ridge  261  and a primary ridge  260 . The channel features on the first and second major surfaces  203 ,  204  of the film  250  can have dimensions of like features shown in  FIG. 2B . 
       FIG. 3  illustrates a cross section of a fluid control device  300  with ridges and channels according to an example embodiment. A fluid control film  301  includes channels  330  that are v-shaped with ridges  320  that define the channels  330 . In this embodiment, the side surfaces  320   b  of the channels  330  are disposed at an angle with respect to the axis normal to the layer surface, i.e., the z axis in  FIG. 3 . As previously discussed, the channels  330  and ridges  320  of the film  301  run along a channel longitudinal axis that is parallel to the longitudinal axis of the film  301 , e.g., the x-axis as previously discussed in connection with  FIG. 1A . The ridges  320  may be an equal distance apart from one another. The film  301  may have an adhesive layer  305  disposed on the bottom surface of fluid control film  301 . As previously discuss in connection with  FIG. 2A , fluid control device  300  may also include a release layer  306  disposed on the adhesive layer  305 . 
     The microchannels described herein may be replicated in a predetermined pattern that form a series of individual open capillary channels that extend along a major surface of the fluid control film. These microreplicated channels formed in sheets or films are generally uniform and regular along substantially each channel length, for example from channel to channel. The film or sheet may be thin, flexible, cost effective to produce, can be formed to possess desired material properties for its intended application and can have, if desired, an attachment means (such as adhesive) on one side thereof to permit ready application to a variety of surfaces in use. 
     The fluid control films discussed herein are capable of spontaneously transporting fluids along the channels by capillary action. Two general factors that influence the ability of fluid control films to spontaneously transport fluids are (i) the geometry or topography of the surface (capillarity, size and shape of the channels) and (ii) the nature of the film surface (e.g., surface energy). To achieve the desired amount of fluid transport capability, the designer may adjust the structure or topography of the fluid control film and/or adjust the surface energy of the fluid control film surface. In order for a channel to function for fluid transport by spontaneous wicking by capillary action, the channel is generally sufficiently hydrophilic to allow the fluid to wet the surfaces of the channel with a contact angle between the fluid and the surface of the fluid control film equal to or less than 90 degrees. 
     In some implementations, the fluid control films described herein can be prepared using an extrusion embossing process that allows continuous and/or roll-to-roll film fabrication. According to one suitable process, a flowable material is continuously brought into line contact with a molding surface of a molding tool. The molding tool includes an embossing pattern cut into the surface of the tool, the embossing pattern being the microchannel pattern of the fluid control film in negative relief. A plurality of microchannels is formed in the flowable material by the molding tool. The flowable material is solidified to form an elongated fluid control film that has a length along a longitudinal axis and a width, the length being greater than the width. The microchannels can be formed along a channel longitudinal axis that is parallel to the longitudinal axis of the film. 
     The flowable material may be extruded from a die directly onto the surface of the molding tool such that flowable material is brought into line contact with the surface of molding tool. The flowable material may comprise, for example, various photocurable, thermally curable, and thermoplastic resin compositions. The line contact is defined by the upstream edge of the resin and moves relative to both molding tool and the flowable material as molding tool rotates. The resulting fluid control film may be a single layer article that can be taken up on a roll to yield the article in the form of a roll good. In some implementations, the fabrication process can further include treatment of the surface of the fluid control film that bears the microchannels, such as plasma deposition of a hydrophilic coating as disclosed herein. In some implementations, the molding tool may be a roll or belt and forms a nip along with an opposing roller. The nip between the molding tool and opposing roller assists in forcing the flowable material into the molding pattern. The spacing of the gap forming the nip can be adjusted to assist in the formation of a predetermined thickness of the fluid control film. Additional information about suitable fabrication processes for the disclosed fluid control films are described in commonly owned U.S. Pat. Nos. 6,375,871 and 6,372,323, each of which is incorporated by reference herein in its respective entirety. 
     The fluid control films discussed herein can be formed from any polymeric materials suitable for casting or embossing including, for example, polyolefins, polyesters, polyamides, poly(vinyl chloride), polyether esters, polyimides, polyesteramide, polyacrylates, polyvinylacetate, hydrolyzed derivatives of polyvinylacetate, etc. Specific embodiments use polyolefins, particularly polyethylene or polypropylene, blends and/or copolymers thereof, and copolymers of propylene and/or ethylene with minor proportions of other monomers, such as vinyl acetate or acrylates such as methyl and butylacrylate. Polyolefins readily replicate the surface of a casting or embossing roll. They are tough, durable and hold their shape well, thus making such films easy to handle after the casting or embossing process. Hydrophilic polyurethanes have physical properties and inherently high surface energy. Alternatively, fluid control films can be cast from thermosets (curable resin materials) such as polyurethanes, acrylates, epoxies and silicones, and cured by exposure radiation (e.g., thermal, UV or E-beam radiation, etc.) or moisture. These materials may contain various additives including surface energy modifiers (such as surfactants and hydrophilic polymers), plasticizers, antioxidants, pigments, release agents, antistatic agents and the like. Suitable fluid control films also can be manufactured using pressure sensitive adhesive materials. In some cases, the channels may be formed using inorganic materials (e.g., glass, ceramics, or metals). Generally, the fluid control film substantially retains its geometry and surface characteristics upon exposure to fluids. 
     In some embodiments, the fluid control film may include a characteristic altering additive or surface coating. Examples of additives include flame retardants, hydrophobics, hydrophylics, antimicrobial agents, inorganics, corrosion inhibitors, metallic particles, glass fibers, fillers, clays and nanoparticles. 
     The surface of the film may be modified to ensure sufficient capillary forces. For example, the surface may be modified to ensure it is sufficiently hydrophilic. The films generally may be modified (e.g., by surface treatment, application of surface coatings or agents), or incorporation of selected agents, such that the film surface is rendered hydrophilic so as to exhibit a contact angle of 90° or less with aqueous fluids. Any suitable known method may be utilized to achieve a hydrophilic surface on fluid control films of the present disclosure. Surface treatments may be employed such as topical application of a surfactant, plasma treatment, vacuum deposition, polymerization of hydrophilic monomers, grafting hydrophilic moieties onto the film surface, corona or flame treatment, etc. Alternatively, a surfactant or other suitable agent may be blended with the resin as an internal characteristic altering additive at the time of film extrusion. Typically, a surfactant is incorporated in the polymeric composition from which the fluid control film is made rather than rely upon topical application of a surfactant coating, since topically applied coatings may tend to fill in (i.e., blunt), the notches of the channels, thereby interfering with the desired fluid flow to which the invention is directed. When a coating is applied, it is generally thin to facilitate a uniform thin layer on the structured surface. An illustrative example of a surfactant that can be incorporated in polyethylene fluid control films is TRITON™ X-100 (available from Union Carbide Corp., Danbury, Conn.), an octylphenoxypolyethoxyethanol nonionic surfactant, e.g., used at between about 0.1 and 0.5 weight percent. Other surfactant materials that are suitable for increased durability requirements include Polystep® B22 (available from Stepan Company, Northfield, Ill.) and TRITON™ X-35 (available from Union Carbide Corp., Danbury, Conn.). 
     A surfactant or mixture of surfactants may be applied to the surface of the fluid control film or impregnated into the article in order to adjust the properties of the fluid control film or article. For example, it may be desired to make the surface of the fluid control film more hydrophilic than the film would be without such a component. 
     A surfactant such as a hydrophilic polymer or mixture of polymers may be applied to the surface of the fluid control film or impregnated into the article in order to adjust the properties of the fluid control film or article. Alternatively, a hydrophilic monomer may be added to the article and polymerized in situ to form an interpenetrating polymer network. For example, a hydrophilic acrylate and initiator could be added and polymerized by heat or actinic radiation. 
     Suitable hydrophilic polymers include: homo and copolymers of ethylene oxide; hydrophilic polymers incorporating vinyl unsaturated monomers such as vinylpyrrolidone, carboxylic acid, sulfonic acid, or phosphonic acid functional acrylates such as acrylic acid, hydroxy functional acrylates such as hydroxyethylacrylate, vinyl acetate and its hydrolyzed derivatives (e.g. polyvinylalcohol), acrylamides, polyethoxylated acrylates, and the like; hydrophilic modified celluloses, as well as polysaccharides such as starch and modified starches, dextran, and the like. 
     As discussed above, a hydrophilic silane or mixture of silanes may be applied to the surface of the fluid control film or impregnated into the article in order to adjust the properties of the fluid control film or article. Suitable silanes include the anionic silanes disclosed in U.S. Pat. No. 5,585,186, as well as non-ionic or cationic hydrophilic silanes. 
     Additional information regarding materials suitable for microchannel fluid control films discussed herein is described in commonly owned U.S. Patent Publication 2005/0106360, which is incorporated herein by reference. 
     In some embodiments, a hydrophilic coating may be deposited on the surface of the fluid control film by plasma deposition, which may occur in a batch-wise process or a continuous process. As used herein, the term “plasma” means a partially ionized gaseous or fluid state of matter containing reactive species which include electrons, ions, neutral molecules, free radicals, and other excited state atoms and molecules. 
     In general, plasma deposition involves moving the fluid control film through a chamber filled with one or more gaseous silicon-containing compounds at a reduced pressure (relative to atmospheric pressure). Power is provided to an electrode located adjacent to, or in contact with film. This creates an electric field, which forms a silicon-rich plasma from the gaseous silicon-containing compounds. 
     Ionized molecules from the plasma then accelerate toward the electrode and impact the surface of the fluid control film. By virtue of this impact, the ionized molecules react with, and covalently bond to, the surface forming a hydrophilic coating. Temperatures for plasma depositing the hydrophilic coating are relatively low (e.g., about 10 degrees C.). This is beneficial because high temperatures required for alternative deposition techniques (e.g., chemical vapor deposition) are known to degrade many materials suitable for multi-layer film  12 , such as polyimides. 
     The extent of the plasma deposition may depend on a variety of processing factors, such as the composition of the gaseous silicon-containing compounds, the presence of other gases, the exposure time of the surface of the fluid control film to the plasma, the level of power provided to the electrode, the gas flow rates, and the reaction chamber pressure. These factors correspondingly help determine a thickness of hydrophilic coating. 
     The hydrophilic coating may include one or more silicon-containing materials, such as silicon/oxygen materials, diamond-like glass (DLG) materials, and combinations thereof. Examples of suitable gaseous silicon-containing compounds for depositing layers of silicon/oxygen materials include silanes (e.g., SiH 4 ). Examples of suitable gaseous silicon-containing compounds for depositing layers of DLG materials include gaseous organosilicon compounds that are in a gaseous state at the reduced pressures of reaction chamber  56 . Examples of suitable organosilicon compounds include trimethylsilane, triethylsilane, trimethoxysilane, triethoxysilane, tetramethylsilane, tetraethylsilane, tetramethoxysilane, tetraethoxysilane, hexamethylcyclotrisiloxane, tetramethylcyclotetrasiloxane, tetraethylcyclotetrasiloxane, octamethylcyclotetrasiloxane, hexamethyldisiloxane, bistrimethylsilylmethane, and combinations thereof. An example of a particularly suitable organosilicon compound includes tetramethylsilane. 
     After completing a plasma deposition process with gaseous silicon-containing compounds, gaseous non-organic compounds may continue to be used for plasma treatment to remove surface methyl groups from the deposited materials. This increases the hydrophilic properties of the resulting hydrophilic coating. 
     Additional information regarding materials and processes for applying a hydrophilic coating to a fluid control film as discussed in this disclosure is described in commonly owned U.S. Patent Publication 2007/0139451, which is incorporated herein by reference. 
     Embodiments of the disclosure are directed to a condensation management apparatus comprising one or more fluid control films that transport condensate along microcapillary channels away from underlying sensitive locations to a designated release location. A condensation management apparatus described herein can be affixed to one or more surfaces of a component that produces condensation, such as surfaces of a refrigeration system. It is understood that apparatuses described herein are not limited to managing condensation on surfaces of a refrigeration system, and can be used on surfaces of any component that produces condensation. 
       FIG. 4  illustrates a refrigeration system  400  comprising a cooled chamber  402  and a conveyor system  404 . The refrigeration system  400  illustrated in  FIG. 4  is referred to as a spiral freezer (available under the trade designation “IQF-SPIRAL FREEZER” from Industrial Refrigeration PVT. LTD., Mumbai, India). The cooled chamber  402  has openings at an entrance  406  and an exit  408 . Product is conveyed through the cooled chamber  402  with sufficient dwell time to reach a desired temperature prior to exiting. For frozen foods, the chamber  402  is typically cooled with liquid ammonia, generating an internal temperature of approximately −20 Fahrenheit (F). Cold internal air mixes with room air at the entrance  406  and exit  408  where product enters and exits the cooled chamber  402 . This mixing of cold and warm air lowers the temperature of the surfaces of the refrigeration system  400  adjacent to the entrance  406  and exit  408 . Moisture present in room air contacts these cooled surfaces of the refrigeration system  400 , generating frost if the surface temperature is below 32 F or condensation if the surface temperature is above 32 F. Condensation formed on the vertical and horizontal external surfaces of the refrigeration system  400  above the entrance  406  and exit  408  is directly over the product on the conveyer system  404 . As the condensation load increases, condensate is eventually pulled by gravity downward and released in droplet form from the vertical and horizontal external surfaces of the refrigeration system  400  above the entrance  406  and exit  408  and onto product on the conveyor system  404 , posing both a food quality and food safety risk. 
     Embodiments of the disclosure address the aforementioned issues by providing a condensation management apparatus that prevents condensation formed on surfaces from contacting product by transporting condensate laterally away from the product. Some embodiments are directed to a condensation management apparatus that prevents condensation formed on vertical surfaces from contacting product by transporting condensate laterally. Other embodiments are directed to a condensation management apparatus that prevents condensation formed on the underside of horizontal surfaces from contacting product by transporting condensate laterally. Further embodiments are directed to a condensation management apparatus that prevents condensation formed on vertical surfaces and on the underside of horizontal surfaces from contacting product by transporting condensate laterally. A condensation management apparatus of the present disclosure is disposable, ensuring a hygienic surface by periodic removal and replacement. 
       FIG. 5  illustrates a condensation management apparatus attached to a component of a refrigeration system in accordance with various embodiments. The component of the refrigeration system  500  illustrated in  FIG. 5  includes a vertical surface  502  comprising an opening  504  dimensioned to receive a conveyor system  510 . The conveyor system  510  is arranged to move product (e.g., food product or ingredients) into and out of the refrigeration system  500 . The opening  504  shown in  FIG. 5  can be the entrance or exit of the refrigeration system  500 . Surfaces of the refrigeration system  500  surrounding the opening  504 , including opposing side surfaces  503  and horizontal surface  505 , are referred to collectively as a freezer tunnel. Cold air internal to the refrigeration system  500  mixes with room air at the opening  504 , lowering the temperature of the vertical surface  502  and the freezer tunnel surfaces  503 ,  505  adjacent to the opening  504 . Condensation formed on the vertical and horizontal surfaces  502 ,  505  above the opening  504  pose a risk of being released in droplet form onto the product on the conveyor system  510 . 
     A microstructured film arrangement  520  is attached to the vertical surface  502  and extends across a portion of the opening  504 . The film arrangement  520  comprises one or more microstructured fluid control films having channels dimensioned to support capillary movement of condensate. The channels of the film arrangement  520  are arranged as shown in  FIG. 1A , such that the channels have a channel longitudinal axis substantially parallel with the longitudinal axis of the film arrangement  520 . The film arrangement  520  includes first and second opposing major surfaces, both of which include the channels. The film arrangement  520  is attached to the vertical surface  502  such that the channel longitudinal axis of the film arrangement  520  is tilted at a tilt angle equal to or greater than a minimum tilt angle with respect to an axis normal to a direction of gravity. With the film arrangement  520  tilted at a tilt angle equal to or greater than the minimum tilt angle, condensation formed on the major surfaces of the film arrangement  520  is transported by the channels laterally to the edge of the opening  504 , away from product on the conveyor system  510 . The film arrangement  520  is periodically removed from the vertical surface  502 , discarded, and replaced, thereby improving hygiene relative to current practices. 
       FIGS. 6A-6C  illustrate the impact of slope of a microstructured fluid control film on the transport of condensate across the film. The microstructured fluid control film  600  illustrated in  FIGS. 6A-6C  includes channels  602  arranged as shown in  FIG. 1A , such that the channels  602  have a channel longitudinal axis  603  substantially parallel with the longitudinal axis of the film  600 . Condensation is formed on the surface of the film  600  until the channels are filled. Once saturated, additional condensation accumulates forming surface droplets  604 . In  FIG. 6A , the channel longitudinal axis  603  is parallel with respect to an axis  601  normal to a direction of gravity. In this orientation, surface droplets increase in size until the force of gravity pulls the surface droplets to the lower edge  606  of the film, resulting in the release of droplets  605 . In  FIG. 6B , the channel longitudinal axis  603  is tilted at a tilt angle α 1  with respect to the axis  601  normal to the direction of gravity. The tilt angle α 1  shown in  FIG. 6B  is less than the minimum tilt angle that prevents the release of droplets  605  from the lower edge  606  of the film  600 . In this orientation, the force of gravity initiates fluid flow towards the channel openings  608  but is insufficient to transport all the surface droplets, resulting in the release of droplets  605  from the lower edge  606  and channel openings  608  along end edge  610  of the film  600 . 
     In  FIG. 6C , the channel longitudinal axis  603  is tilted at an angle α 2  with respect to the axis  601  normal to the direction of gravity. The tilt angle α 2  shown in  FIG. 6C  is equal to or greater than the minimum tilt angle that prevents release of droplets  605  from the lower edge  606  of the film  600 . In this orientation, the force of gravity is greater than the capillary force of the channels  602 , resulting in the release of droplets  605  only from the channel openings  608  along end edge  610  of the film  600 . The inventors have discovered that the minimum tilt angle that prevents release of droplets  605  from the lower edge  606  of the film  600  is about 4 degrees. 
       FIG. 7  illustrates a condensation management apparatus attached to a component of a refrigeration system in accordance with various embodiments. The component of the refrigeration system illustrated in  FIG. 7  includes a vertical surface  702  comprising an opening  704  dimensioned to receive a conveyor system  710 . The conveyor system  710  is arranged to move product  712  (e.g., food product or ingredients) into and out of the refrigeration system. The opening  704  can be the entrance or exit of the refrigeration system. The opening  704  can have a width w and a height h equivalent to dimensions of an entrance or exit of a standard food industry freezer tunnel. For example, the opening  704  can have a width w of 2 feet and a height h of 6 inches. 
     A microstructured film arrangement  705  is attached to the vertical surface  702  and extends across a portion of the opening  704 . In the embodiment shown in  FIG. 7 , the film arrangement  705  includes a first fluid control film  706  and a second fluid control film  708 . The first film  706  includes channels dimensioned to support capillary movement of condensate along opposing first and second major surfaces of the first film  706 . The channels of film  706  are arranged as shown in  FIGS. 1A and 2C , such that the channels have a channel longitudinal axis substantially parallel with the longitudinal axis of the first film  706 . The first film  706  is positioned at a slope across the opening  704  and at a desired height above the product  712 . The first film  706  is positioned such that the channel longitudinal axis  703  of the first film  706  is tilted at a tilt angle α equal to or greater than a minimum tilt angle (e.g., ≥4 degrees) with respect to an axis  701  normal to a direction of gravity. A lower edge  706   a  of the first film  706  extends partially into the opening  704 , with a desired separation provided between the lower edge  706   a  and the product  712 . 
     The second film  708  includes channels dimensioned to support capillary movement of condensate disposed on a first major surface of the second film  708 . A second major surface of the second film  708  includes an adhesive (e.g., pressure sensitive adhesive). In some embodiments, the second major surface of the second film  708  can include channels dimensioned to support capillary movement of condensate. The first film  706  is secured to the opening  704  by the second film  708 . As shown, the second film  708  has a length greater than that of the first film  706 . The second major surface of the second film  708  is adhered to the first major surface of the first film  706  and to the vertical surface  702  of the refrigeration system component. The second film  708  is positioned such that the channel longitudinal axis  707  of the second film  708  it is tilted at a tilt angle α equal to or greater than a minimum tilt angle (e.g., ≥4 degrees) with respect to an axis  701  normal to a direction of gravity. 
     During operation of the refrigeration system, condensation is continuously formed on the vertical surface  702  adjacent to the opening  704 . Condensation formed on the first and second major surfaces of the first film  706  is transported by the channels to the edge of the opening  704 , away from the product  712 . Condensate transported by the first film  706  is released as droplets  720  from channel openings along end edge  706   b  of the first film  706 . Condensation formed on the first major surface of the second film  708  is transported by the channels to the edge of the opening  704 , away from the product  712 . Condensate transported by the second film  708  is released as droplets  720  from channel openings along end edge  708   a  of the second film  708 . 
       FIG. 8  illustrates a condensation management apparatus attached to a component of a refrigeration system in accordance with various embodiments. The component of the refrigeration system illustrated in  FIG. 8  includes a vertical surface  802  comprising an opening  804  dimensioned to receive a conveyor system  810 . The conveyor system  810  is arranged to move product  812  (e.g., food product or ingredients) into and out of the refrigeration system. The opening  804  can be the entrance or exit of the refrigeration system. The opening  804  can have a width w and a height h equivalent to dimensions of an entrance or exit of a standard food industry freezer tunnel (e.g., width w of 2 feet and a height h of 6 inches). 
     A microstructured film arrangement  805  is attached to the vertical surface  802  of the refrigeration system and extends across a portion of the opening  804 . In the embodiment illustrated in  FIG. 8 , the film arrangement  805  includes a single fluid control film  806  having opposing first and second major surface that include channels dimensioned to support capillary movement of condensate. The channels of film  806  are arranged as shown in  FIG. 1A , such that the channels have a channel longitudinal axis substantially parallel with the longitudinal axis of the film  806 . The film  806  can have channels arranged as shown in  FIG. 2C , such that channels are disposed on the first and second major surfaces of the film  806 . 
     The second major surface of the film  806  includes an adhesive  808  disposed on an upper region  806   a  of the film  806 . In some embodiments, the adhesive  808  can be disposed over the channels in the upper region  806   a.  In other embodiments, the upper region  806   a  can be devoid of channels. The adhesive  808  facilitates attachment of the film  806  to the vertical surface  802  of the refrigeration system. The film  806  is positioned on and affixed to the vertical surface  802  such that the channel longitudinal axis  803  of the film  806  is tilted at a tilt angle α equal to or greater than a minimum tilt angle (e.g., ≥4 degrees) with respect to an axis  801  normal to a direction of gravity. A lower edge  806   b  of the film  806  extends partially into the opening  804 , with a desired separation provided between the lower edge  806   a  and the product  812 . 
     During operation of the refrigeration system, condensation is continuously formed on the vertical surface  802  adjacent to the opening  804 . Condensation formed on the first and second major surfaces of the film  806  is transported by the channels to the edge of the opening  804 , away from the product  812 . Condensate transported by the film  806  is released as droplets  820  from channel openings along end edge  806   c  of the film  806 . 
     EXAMPLE 1 
     Determination of Slope Required for Lateral Fluid Transport on a Vertical Surface 
     A cooling apparatus  900 , shown in  FIG. 9 , was built from stainless steel. The cooling apparatus  900  included a container  902  having a length of 24 inches, a height of 6 inches, and a depth of 8 inches. The container  902  was fabricated above a support structure  904  having an opening  906 . The opening  906  had a length of 24 inches, a height of 6 inches, and a depth of 8 inches. The volume  908  of the container  902  was filled with ice and covered with insulating foam  910 , as shown in  FIG. 10 . The ice-filled container  902  generated a surface temperature of 32 F. The cooling apparatus  900  was constructed to simulate the opening (entrance or exit) of a standard food industry freezer tunnel. 
     Preparation of Microchannel Fluid Control Films: 
     Film  1002 , shown in  FIG. 10 , was prepared to include microchannels on one side and an adhesive on the other side. Film  1002  was prepared as described hereinabove using a tool with the pattern oriented to produce microchannels running parallel to the down web film direction (see, e.g.,  FIG. 1A ). The microchannel surface was plasma treated followed by coating the backside with an adhesive as described hereinabove (see, e.g.,  FIG. 2B ). 
     Film  1004  was prepared in the same manner as film  1002 . 
     Film  1006  was prepared to include microchannels on both sides (see, e.g.,  FIG. 2C ). Film  1006  was prepared by first producing a film with microchannels on one side as described hereinabove. To produce film  1006  with channels on both sides, the film  1006  was wound back through the embossing station with the channels facing away from the tool. Channels were formed on the backside by repeating the extrusion embossing process against the film  1006 . The microchannel surface on both sides of the film  1006  was plasma treated as previously described. 
     Attaching the Microchannel Fluid Control Films to the Cooling Apparatus 
     A 25 inch long, 4 inch wide section of film  1006  (microchannels on both sides) was positioned to extend across the front surface  903  of the container  902  and approximately 3 inches over the top of the opening  906 . The right edge of film  1006  was aligned flush with the right side of the container  902 . The left edge of film  1006  extended approximately 1 inch over the left side of the container  902 . Film  1006  was secured in place using a 25 inch long, 4 inch wide section of film  1002  (microchannels on one side, adhesive on the other side) with approximately 1 inch of overlap. The adhesive side of film  1002  secured the film  1002  to the front surface  903  of the container  900  and to film  1006 . Film  1004  (microchannels on one side, adhesive on the other side) was adhered above film  1002  with about a ¼ inch of overlap. In this manner, the entire front surface  903  of the container  902  was covered by films  1002 ,  1004 , and  1006 . 
     For each experiment, films  1002 ,  1004 ,  1006  were adhered to the front surface  903  of the container  902  as described above with increasing slope as shown in Table 1 below. The apparatus  900  was placed in a walk-in environmental chamber with a temperature of 75 F and relative humidity (RH) of 90%. A balance  1010  with a weighing boat  1012  was placed under the left edge of the protruding film  1006  to measure the mass of condensate collected. The experiment was monitored for formation, transport, and release of surface droplets along the bottom edge of film  1006  for a duration of 75 minutes. The rate of collection was determined as the slope of the line formed by the mass plotted as a function of time (see, e.g., the graph of  FIG. 12 ). 
     
       
         
           
               
               
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                   
                   
                   
                 surface 
                 surface 
                 rate of 
               
               
                   
                 % 
                 surface 
                 droplets 
                 droplets 
                 release from 
               
               
                 X 
                 SLOPE 
                 droplets 
                 released from 
                 transported 
                 low side 
               
               
                 (mm) 
                 (X/Y) 
                 formed 
                 bottom edge 
                 to low edge 
                 (g/minute) 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                 0 
                 0 
                 yes 
                 all 
                 no 
                 0 
               
               
                 3 
                 0.5 
                 yes 
                 &lt;10 drops 
                 yes 
                 0.32 
               
               
                 7 
                 1.1 
                 yes 
                 &lt;10 drops 
                 yes 
                 0.33 
               
               
                 16 
                 2.6 
                 yes 
                 none 
                 yes 
                 0.31 
               
               
                 25 
                 4.1 
                 no 
                 N/A 
                 N/A 
                 0.32 
               
               
                 34 
                 5.6 
                 no 
                 N/A 
                 N/A 
                 0.33 
               
               
                   
               
            
           
         
       
     
     EXAMPLE 2 
     Determination of Transport Distance at 4.2% Slope 
     The apparatus  1100  illustrated in  FIG. 11  was used to extend the transport distance relative to the cooling apparatus  900  described in Example 1 above. A 10 foot section of aluminum house gutter  1102  (McMaster Carr, part number 62415T44) was end capped (McMaster Carr part numbers 62415T29 and 62415T31) and sealed with RTV silicone caulk (CRC, Warminster Pa., Part number 14056) to prevent leaks. The gutter  1102  was placed in a walk-in environmental chamber. The gutter  1102  was suspended using four ring stands  1104  and laboratory jacks  1106  (Fisher Scientific, part number S63082) placed approximately 18 inches apart. A 7′-6″ length of film  1110  was adhered to the front face  1103  of the gutter  1102 . The film  1110  was prepared in the same manner as film  1002  in Example 1 above (microchannels on one side, adhesive on the other side). 
     The laboratory jacks  1006  were adjusted to achieve a 4.2% slope (5 inch drop over 10 feet). A 1 inch portion  1112  of the film  1110  near the low end  1107  of the gutter  1102  was peeled back to provide a drainage point for transported condensate. A balance  1120  with an aluminum weighing boat  1122  was placed below the drip point. The volume  1105  of the gutter  1102  was filled with ice and covered with foam insulation (not shown). The mass of condensate released at the drip point above the balance  1120  was recorded every 10 minutes. The film  1110  was monitored for formation, transport, and release of surface droplets over the course of two hours. 
     Condensation was measured at two different conditions, 75 F at 90% RH and 90 F at 90% RH. Elongated surface droplets were observed forming approximately 24 inches from the high end  1109  of the gutter  1102  extending to the low end  1107  at approximately 15 minutes. The droplets were observed to migrate laterally from the high end  1109  to the low end  1107 . The number of droplets on the film surface increased from the high end  1109  to the low end  1107 . Steady-state condensation, transport, and release from the drip point was achieved under both conditions in approximately 30 minutes. The experiment was allowed to proceed for two hours. During this time, all the condensation formed on film  1110  was released at portion  1112 . No surface drops were released from the bottom edge of film  1110  during the experiment. The mass of condensate was measured at steady-state beginning at 70 minutes continuing to 120 minutes as reported in Table 2 below. A graph of this data is shown in  FIG. 12 . It was found that, at a 4.2% slope, the film  1110  can transport approximately 100 g of condensate per hour from a 7 foot by 4 inch area without dripping along the bottom edge of the film  1110 . 
     
       
         
           
               
               
               
             
               
                   
                 TABLE 2 
               
             
            
               
                   
                   
               
               
                   
                 Condensate Mass (grams) 
                   
               
            
           
           
               
               
               
            
               
                 Time (minutes) 
                 75 F./90% RH 
                 90 F./90% RH 
               
               
                   
               
            
           
           
               
               
               
            
               
                 70 
                 0 
                 0 
               
               
                 80 
                 9.28 
                 23.4 
               
               
                 90 
                 21.21 
                 46.8 
               
               
                 100 
                 32.86 
                 70.2 
               
               
                 110 
                 45.21 
                 92.1 
               
               
                 120 
                 57.17 
                 112.2 
               
               
                   
               
            
           
         
       
     
       FIG. 13  is a photograph of the terminus of the film  1110  at the high end  1109  of the gutter  1102 . The photograph was taken at the two hour mark in the experiment at 90 F and 90% RH.  FIG. 13  shows the absence of surface drops being released from the film  1110  relative to the abundance of surface drops formed on the face  1103  of the gutter  1102 . 
       FIG. 14  illustrates a condensation management apparatus attached to a component of a refrigeration system in accordance with various embodiments. The component of the refrigeration system illustrated in  FIG. 14  includes a vertical surface  1402  comprising an opening  1404  dimensioned to receive a conveyor system (not shown). The opening  1404  can be the entrance or exit of the refrigeration system. The opening  1404  can have a width and a height equivalent to dimensions of an entrance or exit of a standard food industry freezer tunnel (e.g., a width of 2 feet and a height of 6 inches). 
     The condensation management apparatus  1400  illustrated in  FIG. 14  includes a first fluid control film  1410  and a second fluid control film  1430 . The first film  1410  includes an array of channels  1412  that extend across a length of the first film  1410 . The channels  1412  have a channel longitudinal axis  1416  that is parallel with a longitudinal axis  1418  of the film  1410 . The second film  1430  includes channels  1432  that are disposed at a bias angle, θ, with respect to a longitudinal axis  1436  of the second film  1430 , the y-axis in  FIG. 12 . The channels  1432  extend across the second film  1430  along a channel longitudinal axis  1434 . The longitudinal axis  1436  of the second film  1430  intersects with the channel longitudinal axis  1434  to form a channel angle  1438 . The channel angle  1438  may be between 0 and 45 degrees. In some embodiments, the channel angle  1438  is less than 45 degrees. In some embodiments, the channel angle  1438  is between about 5 degrees and about 30 degrees, or about 15 degrees to about 25 degrees. In some embodiments, the channel angle  1438  is about 20 degrees. 
     As is shown in  FIG. 14 , an end edge  1420  of the first film  1410  abuts a side edge  1440  of the second film  1430 . Edge openings of the channels  1410  at the end edge  1420  of the first film  1410  are adjacent and fluidically coupled to edge openings of the channels  1432  at the side edge  1440  of the second film  1430 . In this arrangement, the channels  1432  of the second film  1430  are aided by downward gravitational forces creating a siphon effect. This additional capillary force exerted by the channels  1432  of the second film  1430  causes the channels  1432  to pull condensate from the channels  1412  of the first film  1410 . Condensate transferred from the first film  1410  to the second film  1430  is released at an end edge  1442  of the second film  1430  in the form of droplets  1450 . 
     Referring again to  FIG. 5 , and as previously discussed, the microstructured film arrangement  520  attached to the vertical surface  502  of the refrigeration system  500  transports condensate formed on the film arrangement  520  laterally to the edge of the opening  504 , away from product on the conveyor system  510 . The freezer tunnel shown in  FIG. 5  also includes a horizontal surface  505  on which condensation forms due to the mixing of cold air internal of the refrigeration system  500  with room air near the opening  504 . Various embodiments are directed to a microstructured film arrangement configured for attachment on the underside of a horizontal surface that produces condensation, such as horizontal surface  505  of the freezer tunnel shown in  FIG. 5 . The microstructured film is configured to transport condensate laterally from the underside of the horizontal surface  505  to a location at or near a side surface  503  of the freezer tunnel, away from product on the conveyor system  510 . The microstructured film incorporates a capillary siphon arrangement configured to generate a capillary force that pulls condensate from horizontal channels of the film laterally to a condensate release location of the film. 
       FIG. 15A  is a front view of a cooling apparatus  1500  similar to that shown in  FIG. 9 .  FIG. 15B  is a perspective view of the cooling apparatus  1500 . The cooling apparatus  1500  simulates a standard food industry freezer tunnel, such as that shown in  FIGS. 4 and 5 . The cooling apparatus  1500  includes a container  1502  and a support structure  1506  comprising opposing sides  1508 ,  1510  and a base  1509 . A bottom surface  1504  of the container  1502 , the base  1509 , and the opposing sides  1508 ,  1510  define a freezer tunnel having an opening  1505 . With an ice/water mixture present in the container  1502 , the temperature of the bottom surface  1504  of the container  1502  is lowered to 32 F, causing condensation to form on the bottom surface  1504 . 
     A condensation management apparatus  1520  is attached to the horizontal bottom surface  1504  of the container  1502  (e.g., the upper surface of the freezer tunnel) and extends across a portion of the opening  1505 . The condensation management apparatus  1520  includes a microstructured fluid control film  1521  having a first major surface  1521   a  and a second major surface  1521   b.  The first major surface  1521   a  includes channels dimension to support capillary movement of condensate. The channels on the first major surface  1521   a  are arranged as shown in  FIG. 1A , such that the channels have a channel longitudinal axis substantially parallel with the longitudinal axis of the film  1521 . An adhesive (e.g., a pressure sensitive adhesive) is disposed on the second major surface  1521   b  and in contact with the bottom surface  1504  of the container  1502 . The film  1521  can have a construction consistent with that shown in  FIG. 2B . 
     The film  1521  includes a first end  1523  and a second end  1525 . The channels on the first major surface  1521   a  are continuous between the first end  1523  and the second end  1525 . The film  1521  includes a fold  1527  located near the second end  1525 . A condensate collection region  1522  is defined between the fold  1527  and the first end  1523 . A siphon region  1524  is defined between the fold  1527  and the second end  1525 . The second end  1525  of the film  1521  is lower along the direction of gravity than the condensate collection region  1522  (e.g., by at least 0.5 inches). The second end  1525  defines a condensate release location of the film  1521 . The condensate collection region  1522 , the fold  1527 , and the siphon region  1524  define a capillary siphon structure of the microstructured film apparatus  1520 . 
     As is illustrated in  FIG. 15C , longitudinal openings of the channels  1530  within the condensate collection region  1522  are oriented towards a direction of gravity. A channel longitudinal axis  1532  of the channels  1530  within the condensate collection region  1522  is oriented substantially normal to the direction of gravity. As is illustrated in  FIG. 15D , a channel longitudinal axis  1534  of the channels  1530  within the siphon region  1524  is tilted at a tilt angle β with respect to an axis  1535  normal to the direction of gravity. In  FIG. 15D , the channel longitudinal axis  1534  is tilted at a tilt angle β of 90 degrees with respect to the axis  1535  normal to the direction of gravity. The tilt angle β can be any angle from about 5 degrees to about 175 degrees. The second end  1525  of the film  1521  should be at least 0.5 inches lower along the direction of gravity than the condensate collection region  1522 . The condensate collection region  1522  can have a length of up to about 2 feet without condensate releasing from the channels  1530  in the condensate collection region  1522  in the form of droplets. 
     Although not shown in  FIGS. 15A and 15B , the siphon region  1524  can be adhered to a plate mounted to the bottom surface  1504  of the container  1502 . The plate can be oriented to achieve a desired tilt angle β. In some implementations, the siphon region  1524  can be adhered to the side  1510  of the support structure  1506   
     Without being bound to a particular theory, it is hypothesized that the capillary force pulling fluid in both directions with respect to the horizontal channels  1530  is overcome by the body force of gravity pulling the fluid down over the bend in the film  1521  at the fold  1527 . This effect causes a siphon phenomenon that creates void volume resulting in unidirectional transport of fluid towards the fold  1527 . The film  1521  can be applied to the underside of any horizontal surface where condensation is to be managed, and is not limited to use in a freezer tunnel of a refrigeration system. The film  1521  is periodically removed from the horizontal surface, discarded, and replaced, thereby improving hygiene relative to current practices. 
       FIG. 16A  is a front view of a cooling apparatus  1600  having the same construction as that shown in  FIG. 15A .  FIG. 16B  is a perspective view of the cooling apparatus  1600 . The cooling apparatus  1600  simulates a standard food industry freezer tunnel, such as that shown in  FIGS. 4 and 5 . The cooling apparatus  1600  includes a container  1602  and a support structure  1606  comprising opposing sides  1608 ,  1610  and a base  1609 . A bottom surface  1604  of the container  1602 , the base  1609 , and the opposing sides  1608 ,  1610  define a freezer tunnel having an opening  1605 . With an ice/water mixture present in the container  1602 , the temperature of the bottom surface  1604  of the container  1602  is lowered to 32 F, causing condensation to form on the bottom surface  1604 . 
     A condensation management apparatus  1620  is attached to the horizontal bottom surface  1604  of the container  1602  (e.g., upper surface of the freezer tunnel) and extends across a portion of the opening  1605 . The condensation management apparatus  1620  includes a microstructured fluid control film  1621  having a first major surface  1621   a  and a second major surface  1621   b . The first major surface  1621   a  includes channels dimension to support capillary movement of condensate. The channels on the first major surface  1621   a  are arranged as shown in  FIG. 1A , such that the channels have a channel longitudinal axis substantially parallel with the longitudinal axis of the film  1621 . An adhesive (e.g., a pressure sensitive adhesive) is disposed on the second major surface  1621   b  and in contact with the bottom surface  1604  of the container  1602 . The film  1621  can have a construction consistent with that shown in  FIG. 2B . 
     The film  1621  includes a first end  1623  and a second end  1625 . The channels on the first major surface  1621   a  are continuous between the first end  1623  and the second end  1625 . The film  1621  includes a first fold  1629  located near the first end  1623 . The film  1621  also includes a second fold  1627  located near the second end  1625 . A condensate collection region  1622  is defined between the first fold  1629  and the second fold  1627 . A first siphon region  1631  is defined between the first fold  1629  and the first end  1623 . The first end  1623  of the film  1621  is lower (e.g., by at least about 0.5 inches) along the direction of gravity than the condensate collection region  1622 . The first end  1623  defines a first condensate release location of the film  1621 . 
     A second siphon region  1624  is defined between the second fold  1627  and the second end  1625 . The second end  1625  of the film  1621  is lower (e.g., by at least about 0.5 inches) along the direction of gravity than the condensate collection region  1622 . The second end  1625  defines a second condensate release location of the film  1621 . A first half  1622   a  of the condensate collection region  1622 , the first fold  1629 , and the first siphon region  1631  define a first capillary siphon structure of the microstructured film apparatus  1620 . A second half  1622   b  of the condensate collection region  1622 , the second fold  1627 , and the second siphon region  1624  define a second capillary siphon structure of the microstructured film apparatus  1620 . 
     Consistent with the discussion of  FIGS. 15C and 15D , the longitudinal openings of the channels within the condensate collection region  1622  are oriented towards a direction of gravity. A channel longitudinal axis of the channels within the condensate collection region  1622  is oriented substantially normal to the direction of gravity. The channel longitudinal axis of the channels within the first and second siphon regions  1631 ,  1624  is tilted at a tilt angle β with respect to an axis normal to the direction of gravity. In  FIGS. 16A and 16B , the tilt angle β is 90 degrees. As was discussed previously, the tilt angle β can be any angle from about 5 degrees to about 175 degrees. With the provision of two siphon regions  1631 ,  1624 , the condensate collection region  1622  of film  1621  can have a length of up to about 4 feet without condensate releasing from the channels within the condensate collection region  1622  in the form of droplets. The film  1621  can be applied to the underside of any horizontal surface where condensation is to be managed, and is not limited to use in a freezer tunnel of a refrigeration system. The film  1621  is periodically removed from the horizontal surface, discarded, and replaced, thereby improving hygiene relative to current practices. 
     Although not shown in  FIGS. 16A and 16B , the siphon regions  1624 ,  1631  can be adhered to respective plates mounted to the bottom surface  1604  of the container  1602 . The plates can be oriented to achieve a desired tilt angle β. In some implementations, the first siphon region  1631  can be adhered to the side  1608  of the support structure  1606 , and the second siphon region  1624  can be adhered to the side  1610  of the support structure  1606 . 
     EXAMPLE 3 
     Performance of Microstructured Film on a Horizontal Surface Having a Single Fold 
     A cooling apparatus  1500 , as illustrated in  FIGS. 15A and 15B , was built from stainless steel. The cooling apparatus  1500  included a container  1502  having a length of 24 inches, a height of 6 inches, and a depth of 8 inches. The container  1502  was fabricated above a support structure  1506  having an opening  1505 . The opening  1505  had a length of 24 inches, a height of 6 inches, and a depth of 8 inches. The volume of the container  1502  was filled with ice and covered with insulating foam (not shown). The ice-filled container  1502  generated a surface temperature of 32 F. The cooling apparatus  1500  was constructed to simulate the opening (entrance or exit) of a standard food industry freezer tunnel. A panel (not shown) was attached to the backside of the support structure  1506  to block the backend of the opening  1505  to help retain humidity within the opening  1505 . 
     Preparation of Microchannel Fluid Control Film: 
     Film  1521 , shown in  FIGS. 15A and 15B , was prepared to include microchannels on one side and an adhesive on the other side. Film  1521  was prepared as described hereinabove using a tool with the pattern oriented to produce microchannels running parallel to the down web film direction (see, e.g.,  FIG. 1A ). The microchannel surface was plasma treated followed by coating the backside with an adhesive as described hereinabove (see, e.g.,  FIG. 2B ). More specifically, film  1521  was composed of low density polyethylene (Dow 955i LDPE) with a plasma deposited SIO 2 -like hydrophilic coating and a CV60 natural rubber-based hot melt adhesive coated on the side opposite the microchannels. 
     A 4 inch wide film  1521  was applied to the bottom surface  1504  of the container  1502  as shown in  FIGS. 15A and 15B . One of the ends of the film  1521  was folded onto itself at a fold location  1527  to form a pleated siphon region  1524 . The pleated siphon region  1524  had a length of 3 inches. The length of the horizontal portion of the film  1521  adhered to the bottom surface  1504  of the container  1502  was 22 inches. An ice/water mixture was added to the container  1502 . A humidifier tube was placed on the base  1509  of the support structure  1506  near the front of the opening  1505 . The relative humidity within the simulated freezer tunnel rose from 35% to 99% and condensation began to form on the bottom surface  1504  of the container  1502 . 
     A paper towel as well as visual inspection was used to observe whether condensation fell from any area of the film  1521  other than from the end  1525  of the pleated siphon region  1524 . The film  1521  was saturated after approximately 30 minutes. Over the course of four hours, no droplets were released from any area of the film  1521  other than from the end  1525  of the pleated siphon region  1524 . Additionally, any excess water that was added to the horizontal portion of the film  1521  was transported towards the pleated side of the film and released at the end  1525  of the pleated siphon region  1524 . 
     A plastic beaker was weighed and used to collect the liquid released from the end  1525  of the pleated siphon region  1524 . The beaker was weighed again following specific time course studies and the difference between before and after weights reflects the water volume accumulated. Table 3 below shows the results from this experiment. 
     EXAMPLE 4 
     Performance of Microstructured Film on a Horizontal Surface Having Dual Folds 
     A cooling apparatus  1600 , as illustrated in  FIGS. 16A and 16B , was built from stainless steel. The cooling apparatus  1600  included a container  1605  having a length of 24 inches, a height of 6 inches, and a depth of 8 inches. The container  1602  was fabricated above a support structure  1606  having an opening  1605 . The opening  1605  had a length of 24 inches, a height of 6 inches, and a depth of 8 inches. The volume of the container  1602  was filled with ice and covered with insulating foam (not shown). The ice-filled container  1602  generated a surface temperature of 32 F. The cooling apparatus  1600  was constructed to simulate the opening (entrance or exit) of a standard food industry freezer tunnel. A panel (not shown) was attached to the backside of the support structure  1606  to block the backend of the opening  1605  to help retain humidity within the opening  1605 . 
     Preparation of Microchannel Fluid Control Film: 
     Film  1621 , shown in  FIGS. 16A and 16B , was prepared in the same manner as film  1521  of Example 3 above. 
     A 4 inch wide film  1621  was applied to the bottom surface  1604  of the container  1602  as shown in  FIGS. 16A and 16B . A first end of film  1621  was folded onto itself at a first fold location  1629  to form a first pleated siphon region  1631 . A second end of film  1621  was folded onto itself at a second fold location  1627  to form a second pleated siphon region  1624 . The pleated siphon regions  1631 ,  1624  had a length of 3 inches. The length of the horizontal portion of the film  1621  adhered to the bottom surface  1604  of the container  1602  was 22 inches. An ice/water mixture was added to the container  1602 . A humidifier tube was placed on the base  1609  of the support structure  1606  near the front of the opening  1605 . The relative humidity within the simulated freezer tunnel rose from 35% to 99% and condensation began to form on the bottom surface  1604  of the container  1602 . 
     A paper towel as well as visual inspection was used to observe whether condensation fell from any area of the film  1621  other than from the ends  1623 ,  1625  of the pleated siphon regions  1631 ,  1624 . The film  1621  was saturated after approximately 30 minutes. Over the course of four hours, no droplets were released from any area of the film  1621  other than from the ends  1623 ,  1625  of the pleated siphon regions  1631 ,  1624 . Additionally, any excess water that was added to the horizontal portion of the film  1621  was transported towards the pleated sides of the film  1621  and released at the ends  1623 ,  1625  of the pleated siphon regions  1631 ,  1624 . 
     Plastic beakers were weighed and used to collect the liquid released from the ends  1623 ,  1625  of the pleated siphon regions  1631 ,  1624 . The beakers were weighed again following specific time course studies and the difference between before and after weights reflects the water volume accumulated. Table 3 below shows the results from this experiment. 
     
       
         
           
               
               
               
               
               
               
             
               
                 TABLE 3 
               
               
                   
               
               
                   
                 Starting 
                 Ending 
                 Mass of 
                 Total for 
                 Time 
               
               
                 Sample 
                 mass 
                 mass 
                 water 
                 all pleats 
                 Collected 
               
               
                 Information 
                 (g) 
                 (g) 
                 (g) 
                 (g) 
                 (min) 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
            
               
                 Run 1 
                   
                   
                   
                   
                 90 
               
               
                 Single Pleat 
                 9.84 
                 14.15 
                 4.31 
                 4.31 
               
               
                 Double pleat 1 
                 9.91 
                 13.15 
                 3.24 
                 6.00 
               
               
                 Double pleat 2 
                 10.22 
                 12.98 
                 2.76 
               
               
                 Run 2 
                   
                   
                   
                   
                 360 
               
               
                 Single Pleat 
                 9.84 
                 24.53 
                 14.69 
                 14.69 
               
               
                 Double pleat 1 
                 9.91 
                 24.93 
                 15.02 
                 25.41 
               
               
                 Double pleat 2 
                 10.23 
                 20.61 
                 10.39 
               
               
                   
               
            
           
         
       
     
     The results in Table 3 indicate that the addition of more than one pleat over a 2-foot span of film, in the system, can increase the volume of liquid released. The difference in mass collected at 90 versus 360 minutes appears to be linear and proportional to time for each individual pleat. Therefore, it may be favorable to institute a two-pleat system to minimize total liquid held in the film and reduce the probability of premature release. 
     EXAMPLE 5 
     Horizontal Transport Distance using Siphon Regions 
     With reference to  FIG. 17A , a 10-foot section of aluminum house gutter  1700  (McMaster Carr, part number 62415T44) was end capped (McMaster Carr part numbers 62415T29 and 62415T31) and sealed with RTV silicone caulk (CRC, Warminster Pa., Part number 14056) to prevent leaks. Gutter hangers (McMaster Carr, part number 62415T36) were placed in the top opening of the gutter  1700  approximately 18 inches apart. One-half inch aluminum rods were fastened to the gutter clamps using zip ties. The rods were attached to ring stands, suspending the gutter  1700  approximately 18 inches above the base of the stands. The base of the ring stands were placed on 8 inches by 8 inches laboratory jacks (Fisher Scientific part number S63082). The gutter assembly was placed on a table in a walk-in environmental chamber, using the laboratory jacks to level the gutter  1700  horizontally. 
     Microchannel film  1702  with channels oriented parallel to the edge of the film  1702  was prepared as described hereinabove (see, e.g.,  FIGS. 1A and 2B ). A 4 inch wide, 7 foot section of the film  1702  was adhered to the underside  1701  of the gutter  1700 . Siphon regions  1704 ,  1706  were created on each end of the film  1702  by pulling back 3 inches of film  1702 . A balance was placed below each siphon region  1704 ,  1706  to collect condensate in an aluminum weighing dish. 
     The environmental conditions were set to the values shown in Table 4 below and allowed to equilibrate. The gutter  1700  was filled with ice. The top opening was covered with 1 inch Styrofoam insulation to minimize melting. Condensation was collected from the siphon regions  1704 ,  1706 , recording the mass every 10 minutes. The film  1702  was monitored for hanging droplet formation and release along the length of the film  1702 . After each condition, the ice was removed from the gutter  1700  and the film  1702  allowed to completely dry. The mass of condensate collected at the left siphon region  1704  is depicted in  FIG. 17B . The rate of condensation collection was determined for each condition using the slope function in Excel (Microsoft Corporation) for the linear portion of each line and reported in Table 4 below. 
     
       
         
           
               
               
               
             
               
                 TABLE 4 
               
               
                   
               
               
                 Temperature 
                 Relative 
                 Condensate collected at siphon 
               
               
                 (F.) 
                 humidity (%) 
                 region (grams/hour) 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
            
               
                 75 
                 60 
                 12.1 
               
               
                 75 
                 75 
                 16.2 
               
               
                 75 
                 90 
                 23.8 
               
               
                 90 
                 60 
                 21 
               
               
                 90 
                 75 
                 27 
               
               
                 90 
                 90 
                 30.1 
               
               
                   
               
            
           
         
       
     
     After 2 hours, the location of surface hanging droplets along the film  1702  was recorded. For each condition, droplets were observed forming in the center portion of the film  1702 . Regions of the film  1702  nearest the siphon regions  1704 ,  1706  did not contain hanging droplets due to the lateral transport of condensation. The average distance from the siphon regions  1704 ,  1706  to the leading edge of the hanging droplet region was 23 inches, as is reported in Table 5 below. The film length was then shortened to provide a distance between siphon regions  1704 ,  1706  of 36 inches. The experiment was repeated at 90F and 90% RH. No hanging drops were observed on the film  1702  after two hours. 
     
       
         
           
               
               
               
               
               
             
               
                 TABLE 5 
               
               
                   
               
               
                 Distance 
                   
                   
                 Distance from 
                 Distance from 
               
               
                 between 
                   
                   
                 left siphon 
                 right siphon 
               
               
                 siphon 
                   
                 Relative 
                 region to 
                 region to 
               
               
                 regions 
                 Temperature 
                 humidity 
                 first hanging 
                 first hanging 
               
               
                 (inches) 
                 (F.) 
                 (%) 
                 drop (inches) 
                 drop (inches) 
               
               
                   
               
             
            
               
                 72 
                 75 
                 75 
                 20 
                 26 
               
               
                 72 
                 75 
                 90 
                 22 
                 25 
               
               
                 72 
                 90 
                 60 
                 17 
                 25 
               
               
                 72 
                 90 
                 75 
                 23 
                 27 
               
               
                 72 
                 90 
                 90 
                 22 
                 25 
               
               
                 36 
                 90 
                 90 
                 No drops 
                 No drops 
               
               
                   
                   
                   
                 formed 
                 formed 
               
               
                   
               
            
           
         
       
     
     EXAMPLE 6 
     Effect of Siphon Region Length and Angle 
     The gutter  1700  and film  1702  described in Example 5 above were placed on a laboratory bench at ambient conditions (72F/25% RH) and leveled using the laboratory jacks. As shown in  FIG. 17C , a first siphon region  1706  was created on one end of the film  1702  by pulling back 4.5 inches of the film  1702 . The exposed adhesive side was laminated to a 4 inch by 4 inch by 0.070 inch thick stainless steel plate. Extension springs (McMaster Carr part number E9C-SS) were attached to drilled holes in the corners of the plate. The free end of the springs was attached to drilled holes in the laboratory jack plate. The springs were tensioned by pulling the laboratory jack away from the plate followed by securing the base of the jack to the laboratory bench using C-clamps. The height of the laboratory jack was adjusted for each experiment to achieve the angles (a) and distance (L) shown in Table 6 below. For the case of the −170 degree angle, the laboratory jack was reversed and pulled in the opposite direction. 
     A second siphon region was created on the opposite end of the film  1702  by pulling back 7 inches of the film  1702  and folding the film  1702  back on itself to create a 3.25 inch vertical pleat  1704  oriented perpendicular (90 degrees) to the gutter base  1701 . The pleat  1704  was shortened for each experiment to the length shown in Table 6 below using scissors. The combination of cutting and angle adjustment kept the vertical distance from the end of the pleat  1704  to the base  1701  of the gutter  1700  the same for each trial. 
     The gutter  1700  was filled with ice and the top covered with 1 inch Styrofoam insulation. Water vapor generated from a commercial steam cleaner (ProPlus 300CS, Diamer Industries, Worburn Mass.) was directed towards the film  1702  using a back and forth motion until steady state dripping was observed from the siphon regions  1704 ,  1706  and hanging droplets were observed in the center of the film  1702  as described in Example 5 above. Hanging droplets were observed to form in the “clearing zone” near the siphon regions  1704 ,  1706  when the distance L was less than 0.5 inches. 
     
       
         
           
               
               
               
               
             
               
                 TABLE 6 
               
               
                   
               
               
                   
                   
                 Vertical distance 
                 Hanging drops 
               
               
                   
                   
                 from horizontal 
                 formed within 
               
               
                 Siphon angle 
                 Siphon length 
                 plane to end of 
                 18 inches of 
               
               
                 (degrees) 
                 (inches) 
                 siphon (inches) 
                 siphon point 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                 90 
                 3.25 
                   
                 no 
               
               
                 90 
                 2 
                   
                 no 
               
               
                 90 
                 1 
                   
                 no 
               
               
                 90 
                 0.5 
                   
                 no 
               
               
                 90 
                 0.25 
                   
                 yes 
               
               
                 −170 
                 4.5 
                 1 
                 no 
               
               
                 45 
                 4.5 
                 3.25 
                 no 
               
               
                 25 
                 4.5 
                 2 
                 no 
               
               
                 10 
                 4.5 
                 1 
                 no 
               
               
                 5 
                 4.5 
                 0.5 
                 no 
               
               
                 2.5 
                 4.5 
                 0.25 
                 yes 
               
               
                   
               
            
           
         
       
     
     Gutter Assemblies 
     The use of microstructured films described herein may be augmented with gutter-type assemblies, which further collect and consolidate liquid condensate, and move it to a collection or disposal (drain) location. 
       FIG. 18  shows a component  1810 , the various surfaces of which are prone to condensation buildup, as may be seen in a food processing operation. Component  1810  has a length, “L”, and a number of major surfaces including surface  820 , surface  814 , and surface  817 . Surface  820  is a substantially vertical surface, whereas surface  817  is substantially horizontal. Vertical surface  820  interfaces with horizontal surface  817  along substantially lateral edge  822 . Gutter assembly  831  is coupled to vertical surface  820  by a length of microstructured film  1812  as described earlier. The microstructured film is adhesive-backed, and couples component  1810  to gutter assembly  831 . 
     Microstructured film  1812  includes a plurality of channels, less than 500 μm, running parallel to each other, designed to channel and in some embodiments wick water downward to the gutter assembly, and the capillary action of water droplets. The channels may be parallel with the direction of gravity or offset somewhat. If the microstructured film is considered to have a length consistent with its main linear axis  833 , the channels are ideally offset from the main linear axis  833  by between about 15 to 90 degrees, without major negative impact on performance with a vertical surface such as  820 . That is, t 1 , which is the angle between the channels and a line that is perpendicular to the direction of gravity, is between 15 and 90 degrees. 
     Stated conversely, given an axis in the direction of gravity (a gravity axis), the channels generally are parallel to the gravity axis, or may be offset from the gravity axis from zero to 75 degrees. Ideally, they are offset by zero degrees, that is, the channels lead directly down into the gutter assembly, which is described below, and do not veer off course. But in practice a wide berth of angles are possible, so long as sloping downward and terminating in the gutter assembly. The channels support capillary movement of condensate down into the gutter assembly  818 . Condensate drops  820  are shown cascading off the edge of gutter assembly  818 . They may be collected in an appropriate vessel for disposal, or the gutter assembly may itself be coupled directly to a hose, which carries the condensate away and to a drain. 
     A side view of component  1810  is shown in  FIG. 19 . Gutter assembly  818  is shown as a reverse “J” shape (other suitable shapes, such as “U” shape, or other shapes, are possible). The gutter assembly  818  is shown in the FIGs as rectilinear in shape, but other curved shapes, including a circular shape suitable for interfacing with a hose, are also possible. Gutter assembly has two major surfaces: a major outward facing surface  1827 , which in the embodiment shown in  FIG. 19  interfaces with surface  820 , and also downward and outward, and a major inner facing surface  1826 , which interfaces with the adhesive-backed portion of microstructured film  812 , and otherwise interfaces with collected condensate. The adhesive-backed microstructured film includes a portion that couples substantially vertical surface  820 , and then to the inward facing surface  1826  of gutter assembly  818 . Thus, the microstructured film overlaps the lip of the gutter assembly, preventing droplet pinning on the lip and effectively channeling all condensate into the gutter assembly. The channels, or at least some of them, extend from one lateral edge of the microstructured film to the other. The channel openings on the top edge of the film prevent droplet pinning by actively wicking condensate into the microstructured film, which is subsequently transported to the gutter assembly. 
     The gutter assembly may be any suitable J-channel type assembly, made of any suitable material. For example, one suitable J-channel was obtained from Jifram Extrusions (Sheboygan Falls, Wis.), part no. H204, made of polystyrene, and having a wall thickness of 0.045 inch. 
     A shown in  FIGS. 18 and 19 , the gutter assembly is coupled to substantially vertical surface  820  vis-à-vis the adhesive-backed microstructured film  1812 . Gutter assembly  831  comprises a linear axis along its length, as shown by the axis dots  831 . The gutter assembly linear axis in many embodiments will run in a direction approximately parallel with the substantially horizontal edge. Though the gutter assembly in  FIG. 18  is shown wholly positioned below the substantially horizontal edge  822 , other configurations, such as that shown in  FIG. 19 , wherein the gutter assembly is above edge  822 , are also possible. The gutter assembly is in some embodiments ideally sloped at an angle to allow collected condensate to flow to one side of it. Ideally the slope is at least 4 degrees offset from parallel, in all the embodiments shown in this and subsequent figures. 
     Turning now to  FIG. 20 , the same component  1810  is shown as previously, but the surface needing condensate collection is now substantially horizontal surface  817 . Adhesive-backed microstructured film  816  is seen wrapping a vertical surface  813 , then continuing along a substantially horizontal surface  817 , to terminate at and couple to a gutter assembly positioned below lateral edge  822 . Microstructured film  1816  need not wrap up onto vertical surface  813 ; such an embodiment rather is shown to demonstrate that other surface characteristics may be include before, or even after, the substantially horizontal surface. The channels have an average width of less than 500 μm, and are otherwise dimensioned to support capillary movement of condensate. Through capillary movement of liquid condensate along the channels of the microstructured film, water makes it way down vertical surface  813 , along horizontal surface  817 , and then down into gutter assembly  1837 . Adhesive backing surface  835  is shown partially exposed in FIG.  20 —in practice, this portion of the adhesive backing would be minimized or potentially covered with a non-adhesive material, if the adhesive is not desired to be exposed. As shown in  FIG. 21 , which is a side profile view of the embodiment shown in  FIG. 20 , a terminal flange  1841  of microstructured film  1816  is shown, having dimension D 1 . The length of the terminal flange, which is simply the length of microstructured film extending below the horizontal surface  817 , is important for effective drainage of the horizontal surface, because due to capillary action, the additional length has the effect of pulling water downward, thus creating negative capillary pressure further up along the channels, and thus advancing condensate laterally along the horizontal surface, toward the gutter assembly. In most embodiments, the terminal flange, for effective drainage of a horizontal surface, should be at least 0.5 inches, and ideally at least 1 inch. 
       FIG. 22  is a further view of the embodiments shown in  FIGS. 20 and 21 , from the perspective of view  1841  in  FIG. 21 . Surface  813  is seen, and particularly channels  1857 , which here need to be substantially parallel to the direction of gravity at the terminal flange. In other words, considering a hypothetical gravity axis that is the direction of gravity, the microchannels run substantially parallel to this gravity axis  1865 , that is, angle t 2  which is the angle of the channel relative to a line that is perpendicular to the gravity axis, is approximately 90 degrees, though other angles from 75 to 115 degrees, or 80-100 degrees, or 85-95 degrees are also possible, depending on the application (these measurements correspond with channel angle offsets from the gravity axis of zero (ideal), up to 5 degrees, up to 10 degrees, and up to 15 degrees). 
     Turning now to  FIG. 23 , we see a further embodiment of a component  1809  which is similar to the component shown in  FIGS. 20-22 . A side profile view is shown, but instead of having a wholly flat horizontal surface as in  FIGS. 20-22 , substantially horizontal surface  817  has a protuberance  857 , which extends outward from an otherwise horizontal surface a length D 2 . As earlier, a terminal flange is shown having dimension D 1 , along with gutter assembly  1837 , which works in the same manner as discussed earlier. It has been found that even slight protuberances in an otherwise horizontal surface still allow for condensate to be pulled, by capillary forces, into gutter assembly  1837 , so long as D 1  is greater than D 2 . Thus, “substantially horizontal surface” as used in this specification does include protuberances from the horizontal surface that do not exceed the length of the terminal flange. 
       FIG. 24  shows the approaches to condensate collection on horizontal and vertical surfaces of a component, combined. Component  1810  has horizontal surface  817 , and vertical surface  1820 . A pair of back-to-back gutter assemblies  1837 A and  1837 B, is used to collect condensate through capillary movement of water over a microchanneled film as described earlier for both the horizontal and vertical surface. Gutters could be individual gutters placed back-to-back, or could be a single unit with channels sharing a single center rail. 
       FIG. 25  shows an alternative side profile of a gutter assembly  1863 , which forms a partial circle rather than being rectilinear as shown above. A gutter assembly of this design could allow easy interfacing with a hose or tube. 
     Testing of Gutter Assembly 
     An apparatus  1100  illustrated in  FIG. 11  was used to generate condensation on a 53 degree Fahrenheit surface. A 10 foot section of aluminum house gutter  1102  (McMaster Carr, part number 62415T44) was end capped (McMaster Carr part numbers 62415T29 and 62415T31) and sealed with RTV silicone caulk (CRC, Warminster Pa., Part number 14056) to prevent leaks. The aluminum house gutter  1102  was placed in a walk-in environmental chamber. The aluminum house gutter  1102  was suspended using four ring stands  1104  and laboratory jacks  1106  (Fisher Scientific, part number S63082) placed approximately 18 inches apart. A section of ¼ Tygon tubing was looped back and forth inside the gutter approximately 8 times. The open ends of the tubing were connected to a cooled recirculating bath set to 41 degrees F. Water was added to the gutter to approximately 2 inches below the top surface. The environmental chamber was set to 80 degrees F. and 85% relative humidity. After approximately ½ hour the gutter reached an equilibrium surface temperature of 53F. 
     A gutter assembly was attached to the gutter prior to filling with water as follows. The gutter was removed from the ring stands. 4 inch lengths of adhesive-backed microchanneled film with downweb microcapillary channels (0 degree offset from downweb axis) were sequentially coupled to the underside, substantially horizontal surface of the gutter with an approximately ¼ inch overlap. Approximately two inches of film was left unadhered for subsequent attachment to the channel, to act as a terminal flange. This two inch piece was trimmed in a straight line, in dimensions described in Table 7, below. The adhesive side of the terminal flange was then coupled to the inward facing surface of a 6 foot section of a back-to-back gutter assembly, as described above in relation to  FIG. 24 . The back-to-back gutter assembly was assembled using transfer adhesive (3M 9425HT, 3M Company, St. Paul Minn.) to secure the gutters together along the center rail. The house gutter was returned to the ring stand and leveled. The house gutter&#39;s substantially vertical outward surface was next addressed. A 4 inch wide section of adhesive-backed microchanneled film with microchannel orientation of 20 degrees from the downweb axis was coupled lengthwise to the remaining vertical face, with approximately ½ inch on the channel and 3.5 inches on the gutter, as shown in  FIG. 18 . The resulting setup resembled the configuration shown in  FIG. 24 , with both a horizontal and vertical surface being evaluated. This setup was repeated with alternative variables as shown in Table 7, including the use of a surfactant wiped on the drip edge of the terminal flange. The surfactant used was 2-3 drops of Tergitol 15-S-5 (Dow Chemical Company, Midland Mich.), applied using a foam swab (Sterile TX® 712A swabs (CleanTips® ITW Texwipe). It was observed that addition of surfactant aided in the release of condensation into the channel, allowing a shorter distance D 1  to be used. 
     
       
         
           
               
               
               
               
               
               
               
               
               
               
             
               
                 TABLE 7 
               
               
                   
               
               
                   
                 Channel 
                   
                   
                   
                   
                   
                   
                   
                 Hanging 
               
               
                   
                 angle 
                   
                   
                   
                   
                   
                 Surfactant  
                 Surface 
                 Drops on 
               
               
                   
                 (relative  
                 H 
                 W 
                 D1  
                 D2 
                 L 
                 added to 
                 temperature 
                 Horizontal 
               
               
                 Trial 
                 to L) 
                 (in) 
                 (in) 
                 (in) 
                 (in) 
                 (in) 
                 film edge 
                 (F.) 
                 Surface 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
               
               
               
               
               
               
            
               
                  1 
                 90 
                 3.5 
                 4 
                 Between 
                 0 
                 72 
                 N 
                 53 
                 Y 
               
               
                   
                   
                   
                   
                 0.25-0.5 
                   
                   
                   
                   
                   
               
               
                  2 
                 90 
                 3.5 
                 4 
                 Between 
                 0 
                 72 
                 Y 
                 53 
                 N 
               
               
                   
                   
                   
                   
                 0.25-0.5 
                   
                   
                   
                   
                   
               
               
                  3 
                 90 
                 3.5 
                 4 
                 0.5 
                 0 
                 12 
                 N 
                 53 
                 Y 
               
               
                  4 
                 90 
                 3.5 
                 4 
                 0.5 
                 0 
                 12 
                 Y 
                 53 
                 N 
               
               
                  5 
                 90 
                 3.5 
                 4 
                 1 
                 0 
                 12 
                 N 
                 53 
                 N 
               
               
                  6 
                 90 
                 3.5 
                 4 
                 3 
                 0 
                 12 
                 N 
                 53 
                 N 
               
               
                  7 
                 90 
                 2 
                 8 
                 0.5 
                 0 
                 9 
                 N 
                 32 
                 Y 
               
               
                  8 
                 90 
                 2 
                 8 
                 0.5 
                 0 
                 9 
                 Y 
                 32 
                 N 
               
               
                  9 
                 90 
                 2 
                 8 
                 1 
                 0 
                 4 
                 N 
                 32 
                 N 
               
               
                 10 
                 90 
                 2 
                 8 
                 1 
                 0 
                 4 
                 Y 
                 32 
                 N 
               
               
                 11 
                 20 
                 2 
                 5 
                 1.25 
                 0 
                 9 
                 N 
                 32 
                 Y 
               
               
                 12 
                 20 
                 3.5 
                 4 
                 1.5 
                 0 
                 72 
                 N 
                 53 
                 Y 
               
               
                 13 
                 20 
                 3.5 
                 4 
                 1 
                 0 
                 36 
                 N 
                 53 
                 Y 
               
               
                 14 
                 90 
                 2 
                 8 
                 1.25 
                 0.075 
                 4 
                 N 
                 32 
                 N 
               
               
                 15 
                 90 
                 2 
                 8 
                 1.25 
                 0.150 
                 4 
                 N 
                 32 
                 N 
               
               
                 16 
                 90 
                 2 
                 8 
                 1.25 
                 0.225 
                 4 
                 N 
                 32 
                 N 
               
               
                   
               
            
           
         
       
     
     Various embodiments are described herein including the following items. 
     In the forgoing description, reference is made to the accompanying set of drawings that form a part of the description hereof and in which are shown by way of illustration of several specific embodiments. It is to be understood that other embodiments are contemplated and may be made without departing from the scope of the present disclosure. The detailed description, therefore, is not to be taken in a limiting sense. 
     Unless otherwise indicated, all numbers expressing feature sizes, amounts, and physical properties used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the foregoing specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by those skilled in the art utilizing the teachings disclosed herein. The use of numerical ranges by endpoints includes all numbers within that range (e.g. 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.80, 4, and 5) and any range within that range. 
     Particular materials and dimensions thereof recited in the disclosed examples, as well as other conditions and details, should not be construed to unduly limit this disclosure. Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as representative forms of implementing the claims.