Patent Description:
Passenger compartments of vehicles (e.g., aircraft, boats, or the like) may comprise various surfaces, which are frequently touched by passengers or other people. These surfaces may be regularly cleaned or disinfected, but there is a need to mitigate or prevent the presence of microbes on these surfaces between scheduled cleanings. Therefore, being able to readily detect the presence of a previously applied antimicrobial coating or compound to the frequent touchpoint surfaces may be valuable to determine whether reapplication of such antimicrobial coating or compound is warranted. Using conductivity measurements to determine the presence or absence of an antimicrobial coating is known from <CIT>.

A method according to the invention comprises measuring at least one of the conductivity or resistance on a surface of a substrate comprising an antimicrobial system; comparing the measured conductivity or resistance to a reference value; and determining a presence or an absence of the antimicrobial system on the surface. The antimicrobial system comprises a first coating. The first coating comprises an antimicrobial compound. The antimicrobial compound comprises a cationic functional group on the first end and a silane group on the second end, wherein the silane group at least one of binds or couples to the surface of the substrate and the cationic functional group on the first end extends outwardly from the surface of the substrate. In various embodiments, the method may further comprise applying the antimicrobial compound to the surface to form the first coating prior to measuring at least one of the conductivity or resistance on the surface.

In various embodiments, the reference value may comprise a reference conductivity value, wherein, at least one of: in response to the measured conductivity value and the reference conductivity value differing beyond a predetermined threshold, the method may further comprise reapplying the antimicrobial compound to the surface, or in response to the measured conductivity value being less than the reference conductivity value, the method may further comprise reapplying the antimicrobial compound to the surface. In various embodiments, measuring the conductivity of the first coating may be completed via at least one of a voltmeter, a conductivity electrode, or a four-point probe.

In various embodiments, the antimicrobial system may comprise an anionic compound. In various embodiments, the anionic compound may comprise a sulfonate. In various embodiments, the anionic compound may be an anionic surfactant comprising at least one of sodium dodecyl benzene sulfonate, sodium xylene sulfonate, benzenesulfonic acid, or sodium octane-<NUM>-sulphonate monohydrate. In various embodiments, the anionic compound may be comprised in the first coating. In various embodiments, the anionic compound may be comprised in a second coating comprised in the antimicrobial system, wherein the second coating may be disposed on the first coating. In various embodiments, in response to the antimicrobial system comprising the anionic compound, the anionic compound may bind to the cationic functional group of the antimicrobial compound, deactivating a positive charge of the cationic functional group. In such embodiments, measuring at least one of the conductivity or resistance on the surface may comprise measuring the resistance of the antimicrobial system resulting from the anionic compound.

In various embodiments, the reference value may comprise a reference resistance value, wherein, at least one of: in response to the measured resistance value and the reference resistance value differing beyond a predetermined threshold, the method may further comprise reapplying the antimicrobial compound to the surface, or in response to the measured resistance value being greater than the reference resistance value, the method may further comprise reapplying the antimicrobial compound to the surface. In various embodiments, measuring the resistance of the antimicrobial system may be completed via at least one of a high resistance meter, a resistivity cell, or a four-point probe.

In various embodiments, the cationic functional group may be a quaternary ammonium group. According to the invention, the antimicrobial compound comprises further a second end having a silane group, which at least one of binds or couples to the surface of the substrate. According to the invention, the second end of the antimicrobial compound is opposite the first end with a hydrocarbon chain therebetween.

In various embodiments, the surface may be comprised in an aircraft cabin, such that the surface is an aircraft cabin surface. In various embodiments, the aircraft cabin surface may be comprised in at least one of a passenger seat, a passenger suite, a passenger amenity, a control unit, a stowage/luggage compartment, a lavatory, a self-service bar or kiosk, or a galley.

In another aspect of the invention, a system comprises a substrate comprising a surface; an antimicrobial system disposed on the surface; and a device at least one of coupled to or in communication with the surface configured to measure at least one of the conductivity or resistance of the antimicrobial system. The antimicrobial system comprises a first coating comprising an antimicrobial compound. The antimicrobial compound comprises a cationic functional group on the first end and a silane group on the second end, wherein the silane group at least one of binds or couples to the surface of the substrate and the cationic functional group on the first end extends outwardly from the surface of the substrate. In various embodiments, the antimicrobial system may further comprise an anionic surfactant, and wherein the device measures the resistance of the antimicrobial system. In various embodiments, the substrate may be comprised in an aircraft and comprises at least one of a passenger seat, a passenger suite, a passenger amenity, a control unit, a stowage/luggage bin, a lavatory, a self-service bar or kiosk, or a galley.

A more complete understanding of the present disclosure, however, may best be obtained by referring to the detailed description and claims when considered in connection with the drawing figures. Elements with the like element numbering throughout the figures are intended to be the same.

All ranges may include the upper and lower values, and all ranges and ratio limits disclosed herein may be combined. It is to be understood that unless specifically stated otherwise, references to "a," "an," and/or "the" may include one or more than one and that reference to an item in the singular may also include the item in the plural.

The detailed description of various embodiments herein makes reference to the accompanying drawings, which show various embodiments by way of illustration. While these various embodiments are described in sufficient detail to enable those skilled in the art to practice the disclosure, it should be understood that other embodiments may be realized and that logical, chemical, and mechanical changes may be made within the scope of the claims. For example, the steps recited in any of the method or process descriptions may be executed in any order or combination and are not necessarily limited to the order or combination presented. Also, any reference to attached, fixed, connected, or the like may include permanent, removable, temporary, partial, full, and/or any other possible attachment option.

Aircraft, such as aircraft <NUM> depicted in <FIG>, may comprise an interior cabin inside aircraft body <NUM>. <FIG> depicts an interior cabin <NUM> inside an aircraft (e.g., aircraft <NUM>) including various substrates having surfaces which may be frequent touchpoints by passengers or other people present in interior cabin <NUM>. For example, the substrates having frequent touchpoint surfaces may be comprised in or on veneer panels <NUM> (e.g., wall or table surfaces), a passenger seat <NUM>, a passenger amenity (e.g., a self-service bar or kiosk <NUM>), a control unit, a stowage/luggage compartment <NUM>, a lavatory <NUM>, a galley, and/or the like. Other vehicles, such as automobiles and boats, may comprise the same or similar surfaces in an interior compartment.

In various embodiments, an antimicrobial compound may be applied to such frequent touchpoint surfaces. The antimicrobial compound may be configured to attract and neutralize, kill, and/or inactivate microbes (e.g., bacteria, viruses, and/or the like) that come in contact with the antimicrobial compound.

With reference to <FIG>, the antimicrobial compound may be comprised in an antimicrobial system. The antimicrobial system may comprise a coating or layer disposed on a frequent touchpoint surface of a substrate. With reference to <FIG>, a cross section of a substrate <NUM> having an outer surface <NUM> (e.g., a frequent touchpoint surface) is depicted, in accordance with various embodiments. Substrate <NUM> may comprise any suitable material, such as synthetic or natural fabric surfaces, plastics, metals, composites and composite finishes, wood, glass, leather, and/or the like. In various embodiments, outer surface <NUM> may be the surface presented to or exposed to passengers or other people. Therefore, outer surface <NUM> may frequently be exposed to or receive microbes from the people coming in contact with outer surface <NUM>, directly or indirectly.

Substrate <NUM> and its outer surface <NUM> may comprise an antimicrobial system 205A disposed thereon and/or coupled thereto. According to the invention, the antimicrobial system 205A comprises a first coating <NUM> disposed on outer surface <NUM>. First coating <NUM> may be an antimicrobial coating and/or comprise an antimicrobial compound. First coating <NUM> and/or the antimicrobial compound may be coupled (e.g., grafted) and/or bound (e.g. via chemical, electrostatic, and/or electrochemical bonds) to outer surface <NUM>. The antimicrobial compound may comprise any suitable compound for attracting, neutralizing, killing, and/or deactivating microbes. According to the invention, the antimicrobial compound comprises a cationic functional group on the first end and a silane group on the second end, wherein the silane group at least one of binds or couples to the surface of the substrate and the cationic functional group on the first end extends outwardly from the surface of the substrate. In various embodiments, the cationic functional group may comprise a quaternary ammonium group ("QUAT"). For example, the antimicrobial compound may comprise a silane-functionalized QUAT. In various embodiments, the cationic functional group may extend outwardly from outer surface <NUM>, such that the cationic functional group is further from outer surface <NUM> than the second end of the antimicrobial compound. The cationic functional group may be the portion of the antimicrobial compound extending outwardly furthest from outer surface <NUM>. The cationic functional group may attract microorganisms (e.g., bacteria or viruses), which may be negatively charged, and then the antimicrobial compound may neutralize, kill, or deactivate such microorganism. The antimicrobial compound may couple or bind (e.g., covalently) to substrate <NUM>, resulting in layers or coatings (e.g., first coating <NUM>) persisting for extended periods of time (e.g., multiple months).

In various embodiments, the antimicrobial coating (e.g., first coating <NUM>) may be a monolayer. In various embodiments, the antimicrobial coating may comprise a thickness between a single molecular layer and <NUM> micrometers (µm), or between <NUM> and <NUM> nanometers (nm). Such thicknesses of first coating <NUM> may cause first coating <NUM> to be invisible to the naked human eye, and susceptible to wear and erosion from physical contact (especially on frequent touchpoint surfaces).

With additional reference to <FIG>, a method <NUM> for detecting the presence (or absence) of an antimicrobial coating (e.g., first coating <NUM>) is valuable to indicate when reapplication of the antimicrobial compound or coating may be warranted or necessary. For example, an antimicrobial compound may be applied to outer surface <NUM> (step <NUM>) of substrate <NUM>. The antimicrobial compound may be any of those discussed herein. The antimicrobial compound may be comprised in a solution that is applied to the surface in any suitable manner, for example by spraying (e.g., electrostatic spray application), dipping, wiping, and/or the like. The antimicrobial compound or solution may be dried to form the antimicrobial coating (e.g., first coating <NUM>) on the surface. Because first coating <NUM> comprises an antimicrobial compound having a cationic functional group, which may be at or proximate an outer surface of first coating <NUM> (opposite the inner surfaces of first coating <NUM> coupled to the substrate), first coating <NUM> and the antimicrobial compound comprised therein may conduct electricity. Therefore, by measuring the conductivity of outer surface <NUM> (step <NUM>), one may be able to determine the presence (or absence) of first coating <NUM> and/or the antimicrobial compound on outer surface <NUM> (step <NUM>).

The conductivity of surface <NUM> (and first coating <NUM> comprising the antimicrobial compound) may be measured in any suitable manner or by any suitable device (e.g., conductivity measuring device 250A). For example, the conductivity may be measured using a voltmeter, a conductivity electrode, a four-point probe, and/or the like, being applied to (e.g., coupled to and/or in communication with (e.g., electronic communication)) the surface.

In response to receiving a measured conductivity value, to determine the presence (or absence) of first coating <NUM> and the antimicrobial compound on outer surface <NUM> (step <NUM>), in various embodiments, the measured conductivity value may be compared to a reference conductivity value (step <NUM>). The reference conductivity value may be a value to which a measured conductivity value may be compared to aid in determining the presence (or absence) of the first coating and the antimicrobial compound on the surface. For example, the reference conductivity value of the surface may be the conductivity value that results from a freshly applied first coating comprising an antimicrobial compound (or a first coating having little or no wear or erosion), referred to herein as a baseline conductivity value. Therefore, if the measured conductivity value is less than the baseline conductivity value, it may be concluded that at least a portion of the first coating comprising the antimicrobial compound may have been removed. As another example, the reference conductivity value may be a threshold conductivity value, and in response to the measured conductivity value being less than the threshold conductivity value (or differing therefrom beyond a predetermined threshold), reapplication of the antimicrobial coating to the surface may be warranted to replenish the antimicrobial compound thereon to a desired level (e.g., such that the conductivity of the surface and the antimicrobial compound thereon is above the threshold conductivity value). As yet another example, the reference conductivity value may be a threshold conductivity differential value, which may be predetermined and/or indicate the maximum difference between the measured conductivity value and the baseline conductivity value before indicating that reapplication of the antimicrobial compound may be appropriate. That is, if the difference between the measured conductivity value and the baseline conductivity value is beyond the threshold conductivity differential value, reapplication of the antimicrobial coating may be warranted.

In response to the measured conductivity value indicating that reapplication of the antimicrobial compound may be appropriate (e.g., if there is no conductivity, or conductivity that is lower than a desired level, for example, based on comparing the measured conductivity value to the reference conductivity value), the antimicrobial compound (or a solution comprising the same) may be reapplied onto the surface (step <NUM>).

In various embodiments, an antimicrobial system on a substrate surface may further comprise an anionic compound. Accordingly, with additional reference back to <FIG>, detecting the presence (or absence) of the antimicrobial compound or coating on a surface (method <NUM>) may further comprise applying an anionic compound to the surface (step <NUM>). In various embodiments, the anionic compound may be comprised in the antimicrobial solution or coating (e.g., comprised in first coating <NUM>). Therefore, to dispose first coating <NUM> onto the substrate surface, an antimicrobial compound may be combined with an anionic compound, and then such a composition may be applied to the substrate surface. In various embodiments, the anionic compound may be comprised in a coating separate from the antimicrobial coating, as depicted in <FIG> showing antimicrobial system 205B comprising first coating <NUM> having an antimicrobial compound and second coating <NUM> having an anionic compound disposed on first coating <NUM>, such that first coating <NUM> is disposed between second coating <NUM> and the outer surface <NUM>. The anionic compound may be comprised in a solution that is applied to the surface in any suitable manner, for example by spraying (e.g., electrostatic spray application), dipping, wiping, and/or the like. The anionic compound or solution may be dried to form second coating <NUM> on the surface.

The anionic compound may be any suitable compound. In various embodiments, the anionic compound may comprise a sulfonate (e.g., a sulfonate group or ion). In various embodiments, the anionic compound may comprise an anionic surfactant. For example, the anionic surfactant may comprise sodium dodecyl benzene sulfonate, sodium xylene sulfonate, benzenesulfonic acid, and/or sodium octane-<NUM>-sulphonate monohydrate.

The anionic compound may bind to the cationic functional group of the antimicrobial compound and deactivate the positive charge thereof. The cationic functional group still may remain positively charged, thereby continuing to attract microbes and functioning as an antimicrobial compound. With the positive charge of the cationic functional group deactivated, a method of detecting the presence (or absence) of the antimicrobial compound or coating on a surface (shown in method <NUM>) may comprise measuring the resistance of the surface (step <NUM>) with the antimicrobial system disposed thereon. By measuring the resistance of outer surface <NUM> (step <NUM>), one may be able to determine the presence (or absence) of first coating <NUM> and the antimicrobial compound on outer surface <NUM> (step <NUM>). For example, as the antimicrobial compound or coating is worn or eroded from the surface, and the anionic compound remains, the resistance of the surface may increase.

The resistance of surface <NUM> (and the antimicrobial system disposed thereon) may be measured in any suitable manner or by any suitable device (e.g., resistance measuring device 250B). For example, the resistance may be measured using a high resistance meter, a resistivity cell, a four-point probe, and/or the like, being applied to (e.g., coupled to and/or in communication with (e.g., electronic communication)) the surface.

In response to receiving a measured resistance value, to determine the presence (or absence) of first coating <NUM> and the antimicrobial compound on outer surface <NUM> (step <NUM>), in various embodiments, the measured resistance value may be compared to a reference resistance value (step <NUM>). The reference resistance value may be a value to which a measured resistance value may be compared to aid in determining the presence (or absence) of the antimicrobial compound on the surface. For example, the reference resistance value of the surface may be the resistance value that results from a freshly applied first coating comprising an antimicrobial compound and second coating having the anionic compound (or a first coating and second coating having little or no wear or erosion), referred to herein as a baseline resistance value. The amount of second coating comprising the anionic compound applied to the substrate surface and the antimicrobial coating may be controlled to achieve a desired baseline resistance value (e.g., neutralizing the positive charge of the antimicrobial compound, such that the resistance is zero). Therefore, if the measured resistance value is greater than the baseline resistance value, it may be concluded that at least a portion of the first coating comprising the antimicrobial compound may have been removed. As another example, the reference resistance value may be a threshold resistance value, and in response to the measured resistance value being greater than the threshold resistance value (or differing therefrom beyond a predetermined threshold), reapplication of the antimicrobial coating to the surface may be warranted to replenish the antimicrobial compound thereon to a desired level (e.g., such that the resistance of the surface and the antimicrobial system thereon is below the threshold resistance value). As yet another example, the reference resistance value may be a threshold resistance differential value, which may be predetermined and/or indicate the maximum difference between the measured resistance value and the baseline resistance value before indicating that reapplication of the antimicrobial compound may be appropriate. That is, if the difference between the measured resistance value and the baseline resistance value is beyond the threshold resistance differential value, reapplication of the antimicrobial coating may be warranted.

In response to the measured resistance value indicating that reapplication of the antimicrobial compound may be appropriate (e.g., resistance is greater than a desired level, for example, based on comparing the measured resistance value to the reference resistance value), the antimicrobial compound (or a solution comprising the same) may be reapplied onto the surface (step <NUM>).

The methods and systems discussed herein involving an antimicrobial system (comprising an antimicrobial compound and/or an anionic compound) may allow determination of whether the antimicrobial compound or coating (or a sufficient amount thereof) remains present on a substrate surface by measuring the conductivity and/or resistance of the surface and the coatings thereon. Other antimicrobial detection methods may be less precise or destructive to the underlying substrate (e.g., visual methods, which may result in staining the substrate).

Additionally, in various embodiments, with the conductivity and/or resistance measurements of the surfaces comprising antimicrobial compounds, a quantitative analysis of how much of the remaining antimicrobial compound and/or coating may be determined (e.g., as part of determining the presence or absence of the antimicrobial compound on the substrate surface (step <NUM>)). Such a quantitative analysis may be performed, for example, by comparing the measured value to a pre-established baseline value (such as the baseline conductivity value and baseline resistance value discussed herein). The difference between such values may allow determination of the amount or percentage of antimicrobial compound or coating remaining on the surface, or the amount or percentage of antimicrobial compound or coating that has been lost. Also, such a quantitative analysis may be conducted over a larger surface (e.g., the entire surface area of a surface) than other antimicrobial detection methods, by measuring the surface conductivity or resistance.

In the detailed description herein, references to "one embodiment", "an embodiment", "various embodiments", etc., indicate that the embodiment described may include a particular feature, structure, or characteristic, but every embodiment may not necessarily include the particular feature, structure, or characteristic.

Claim 1:
A method, comprising:
measuring at least one of the conductivity or resistance on a surface (<NUM>) of a substrate (<NUM>) comprising an antimicrobial system, wherein the antimicrobial system comprises a first coating (<NUM>), wherein the first coating (<NUM>) comprises an antimicrobial compound, wherein the antimicrobial compound comprises a first end and a second end opposite the first end with a hydrocarbon chain therebetween, wherein the antimicrobial compound comprises a cationic functional group on the first end and a silane group on the second end,_wherein the silane group at least one of binds or couples to the surface of the substrate and the cationic functional group on the first end extends outwardly from the surface of the substrate;
comparing the measured conductivity or resistance to a reference value; and
determining a presence or an absence of the first coating (<NUM>) on the surface (<NUM>).