Patent Description:
This Utility Patent Application is based on a Provisional Application No. <CIT>.

The present invention is directed to energy saving and environmentally responsive smart materials, and in particular, to production of composite textile materials capable of self-regulation of thermal exchange between a wearer's body and the environment.

The present invention also addresses fabrication of smart textiles from bi-morph meta fibers capable of self-adjustment of the textile's infrared emissivity to a heat/humidity comfort zone in response to environmental parameters fluctuations.

In overall concept, the subject invention addresses a smart textile fabricated from yarns containing bi-morph meta fibers formed through spinning of two antagonistic polymer (hydrophobic and hydrophilic) components with optical nanostructures embedded at least in one polymer component, and heat training (setting) of the yarns in a predetermined heat/humidity diapazone to attain environmentally responsive properties through modulation of the electromagnetic coupling between the optical nanostructures in the fibers resulting in self-regulation of the heat transport in the smart textile to remain in the heat/humidity comfort zone.

In addition, the present invention is directed to the possibility of manufacturing of wearable garments from bi-morph meta fibers which are embedded with selected optical nanostructures incorporated in the fibers and demonstrating a dynamic humidity responsive behavior due to an effective electromagnetic coupling of the optical nanostructures self-adjustment.

The present invention also addresses the possibility of a single-step spinning process for manufacturing a meta fiber-based material having a tunable infrared emissivity and heat transport adjustability in response to the environmental humidity fluctuations in order to maintain a wearer's thermal comfort zone without external power consumption.

Energy saving is an important issue for development of human society and civilization. , about <NUM>% of the total energy produced is consumed by residential and commercial buildings. Approximately <NUM>% of the consumed energy is spent for heating and/or cooling in order to maintain thermal comfort for the inhabitants in the buildings. Such consumption of energy for heating or cooling of vast spaces of buildings results in substantial energy waste that contributes to deleterious global climate changing.

In view of such issue, there is a vast commercial interest in developing wearable clothing technologies that can provide comfort zone for wearers of the clothing that would reduce a large amount of energy consumption for environment control in the buildings.

Usage of such clothing technologies can be even more beneficial in places other than residential or office buildings, such as, in severe working environments, for example, battle fields or hot and humid industrial settings. In these extreme settings, the regulation of the body temperature and heat transport through a wearer's clothing would be extremely important for survival of people exposed to such severe environmental conditions.

Environmentally responsive textile materials for clothing can also be beneficial in an enhanced caring for infants and medical patients who require personal attendance to fulfill their thermal comfort needs.

Bi-component fibers are fabricated with two antagonistic polymers having different chemical and/or physical properties. In the manufacturing process, the two polymers are extruded from the same spinneret with both polymers within the same filament.

A difference in shrinkage induced by the environmental stimuli, such as, for example, heat and/or humidity fluctuations, between the antagonistic polymers in the bi-component fibers results in a strong environmental response of the bi-component fibers.

Examples of the bi-component fiber based commercial products include Nike's AeroReact™ and Mitsubishi Rayon's Ventcool™ that use a perspiration responsive fabric designed to maintain a wearer's skin dry by increasing air spaces in the textiles to promote sweat wicking. However, these technologies are neither capable of active regulation of the infrared radiation (which is the main thermal transport channel for heat dissipation from a human body to the environment), nor of active dynamic tunability of the infrared emissivity in order to self-regulate the heat transfer in response to environmental changes.

Infrared clothing is commercially available that incorporates nanoparticles to enhance the absorption of infrared radiation useful in hyperthermia therapy. However, the existing technology is a passive technology, and thus is not capable of self-regulation of the heat transfer through infrared radiation.

It would be highly desirable to further advance the fabrication of smart textiles from bi-component meta fibers capable of self-regulation of the heat transfer via active modulation of the infrared (IR) radiation and dynamic adjustment of the IR emissivity, as a channel of the heat transfer, to predetermined heat/humidity comfort zone responsive to the environmental deviation therefrom.

<CIT> discloses a composite fabric having self-regulating infrared emissivity that includes meta fibers formed with optical nanostructures and an environment (temperature and/or moisture) responsive mechanism configured to adjust a relative disposition between the optical structures to control the electromagnetic coupling therebetween. This is said to regulate the infrared emissivity of the composite fabric to maintain a user of the fabric in a temperature/moisture comfort zone.

It is therefore an object of the present invention to provide composite materials manufactured from bi-component fibers with incorporated optical nanostructures that are configured with an optical coupling mechanism capable of an active tunability of the infrared emissivity responsive to the environmental changes.

It is another object of the present invention to provide a smart textile capable of self-regulated thermal comfort for a wearer of the clothing made from the smart textile fabricated from bi-component meta fibers incorporated with optical nanostructures.

It is a further object of the present invention to fabricate smart textiles from bi-component (antagonistic polymer components) fibers, capable of dynamic mechanical changes due to the difference in moisture absorption by antagonistic polymers (one hydrophilic and the other hydrophobic), and demonstrating the actively tunable infrared emissivity resulting from the modulation in the electromagnetic coupling of the optical nanostructures embedded in the hydrophobic component of the fibers which is caused by the dynamically changing displacement of neighboring fibers with the purpose of maintaining the wearer's comfort zone in changing environments.

It is an additional object of the present invention to provide a smart textile formed with composite fibers manufactured with at least two physically different base polymers and an optical nanostructure embedded therein to realize the meta-cooling textile (MCT) technology which would be capable of modulating the infrared emissivity of the textile in response to thermal discomfort, thus providing thermal regulation in a self-powered fashion (without the need for an extra power to maintain thermal comfort).

Furthermore, it is an object of the present invention to manufacture smart textiles with composite fibers capable of the dynamical tuning of the infrared radiation (as a primary channel for heat transfer through the textile) and of the energy exchange between the wearer's body and the surrounding environment, thus providing efficient localized thermal management.

The present invention is also directed to the humidity responsive bi-component meta fibers fabricated from polymer composites having optical nanostructures incorporated therein, which, depending on the relative humidity and/or perspiration level, curls or straightens, thus modulating a relative disposition of optical nanostructures in the neighboring meta fibers to control the electromagnetic coupling between optical nanostructures in the neighboring meta fibers and to adjust the thermal radiation in the infrared range.

In addition, it is an object of the present invention to provide a composite fiber capable of a reversible self-regulation of a thermal transport mechanism, where the increase or decrease of the humidity level causes straightening or curling, respectively, of the meta fibers, that results in modulation of a relative displacement between the neighboring meta fibers, leading to enhanced or reduced infrared emissivity of the meta fibers, causing, in its turn, the adjustment of the heat transfer through the meta fibers.

It is a further object of the present disclosure to provide a melt spinning process for production of meta-cooling fibers, through the process steps, including: (a) pre-compounding of optical nanostructures into a hydrophobic polymer precursor, followed by (b) direct spinning of the hydrophobic polymer precursor with an antagonistic (hydrophilic) humidity responsive polymer precursor through a spinneret configured to form various configurations of bi-component meta fibers capable of a dynamic humidity response and self-regulated infrared emissivity.

It is also an object of the present invention to provide a heat "training" process to define an "open" state of the meta-cooling fibers under a wet condition, where the fibers are straightened to decrease the relative disposition of neighboring fibers to allow maximum electromagnetic coupling between optical nanostructures in the neighboring fibers, followed by the heat "training" step to define a "close" state of the meta-cooling fibers under dry condition, where the fibers are curled to increase the relative disposition of neighboring fibers to attain a minimum electromagnetic coupling between the optical nanostructures in the neighboring fibers.

It is a further object of the present disclosure to provide a scalable manufacturing process for production of meta-cooling fibers and textiles through the steps of: (a) compounding optical nanostructures with a polymer melt, (b) melt spinning of bi-component fibers, and (c) heat setting (training) to generate a dynamic humidity response of meta-cooling fibers.

It is still an object of the present invention to fabricate energy saving and environmentally responsive composite fibers for various applications, especially for on-body wearable humidity responsive clothing technologies, athletic apparel, medical and military clothing, as well as infant clothing, to attain an efficient and rapid self-cooling of the clothing, and for wearable technologies suitable in severe working environments capable of an effective self-regulation of thermal transport from a wearer's body.

The present invention relates to a textile composed of meta fibers, comprising a plurality of meta fibers arranged into a yarn, each of said meta fibers including a hydrophobic component of a first spinnable polymer material; a hydrophilic component of a second spinnable polymer material; and a plurality of optical nanostructures embedded in said hydrophobic component, as defined in claim <NUM>. Preferred embodiments are defined in dependent claims <NUM>-<NUM>.

In one aspect, the present invention addresses a smart textile fabricated from meta fibers. The meta fibers in the smart textile are fabricated as bi-component fibers configured with first and second antagonistic polymer components, one of which is a hydrophobic polymer component, while another is a hydrophilic polymer component. The hydrophobic and hydrophilic polymer components are combined in each bi-component fiber in either an eccentric sheath-core arrangement, or a side-by-side (key-lock) structural arrangement. In the eccentric sheath-core structure and arrangement, the hydrophilic polymer is used as a sheath, and the hydrophobic polymer is used as a core.

The base bi-component fiber further includes optical nanostructures dispersed in the hydrophobic polymer matrix for supporting the electromagnetic coupling between the optical nanostructures in the neighboring meta fibers. The electromagnetic coupling is determined by a distance (spacing) between the fibers, and determines the infrared emissivity of the composite fabric (smart textile).

In one embodiment, the subject bi-component meta fiber includes a humidity responsive mechanism ensured by the humidity responsive polymers.

The humidity responsive mechanism operates as follows:.

The optical nanostructures are embedded in the hydrophobic component of the meta fibers by compounding the optical nanostructures at a desired concentration prior to the spinning process. The optical nanostructures contemplated for inclusion into the subject meta fibers may include single-walled carbon nanotubes (CNT), double-walled carbon nanotubes, few-walled carbon nanotubes, multi-walled carbon nanotubes, carbon nanohorns, carbon fibers, graphene, graphene oxides, carbon black, silver nanowires, copper nanowires, silicon nanowires, gold nanowires, gold nanoparticles, as well as their combinations.

The humidity responsive (i.e. hydrophilic) polymer contemplated for usage in the subject meta fibers may include Nylon <NUM>, Nylon <NUM>, polyurethane, and combinations thereof.

The hydrophobic polymer may include polyethylene, polyethylene terephthalate, polypropylene, polybutylene terephthalate, and combinations thereof.

Disclosed herein is a method of manufacturing a composite meta fiber material with self-regulated infrared emissivity responsive to the environmental humidity fluctuations, which comprises the steps of:.

These and other objects and advantages of the present system and method will be more apparent from reading the following Detailed Description of the subject invention in conjunction with the Patent Drawing figures.

The subject meta cooling fibers are envisioned as the foundation for energy saving and environmentally responsive garments fabricated from smart composite materials capable of actively maintaining a heat/humidity comfort zone for a wearer of such garment, where the heat transfer from a wearer's body is self-regulated based on the infrared radiation changes in response to the environmental humidity fluctuations, as well as where a humidity response mechanism is implemented to maintain the clothes in the temperature/humidity comfort zone.

Referring to <FIG>, the subject meta fabrics <NUM> are arranged into yarns <NUM>, which are further knitted into the smart textile (fabric) <NUM>.

The human body absorbs and loses heat primarily by the infrared radiation with the peak at ~<NUM> (<NPL>). The subject meta cooling fibers <NUM> forming the smart fabric <NUM> use the IR radiation-based heat transport mechanism for maintaining a thermal comfort zone for a wearer of a garment formed from the subject smart textile <NUM> by self-regulating the infrared emissivity in response to variations of the environmental humidity and /or perspiration level.

Optical nanostructures <NUM> are embedded in the meta fibers <NUM>. The weight of the optical nanostructures <NUM> may fall in the range selected from a group of <NUM>-<NUM>%, <NUM>-<NUM>%, and <NUM>-<NUM>% of the weight of the hydrophobic component <NUM> in the meta fiber <NUM>. The subject meta-cooling fibers <NUM> operate by modulating their infrared emissivity through changing the electromagnetic coupling between the optical nanostructures <NUM> embedded in the neighboring meta-cooling fibers <NUM> within each yarn <NUM>.

Referring to <FIG>, when the humidity in the environment is low (dry environment or low perspiration level), the meta fibers <NUM> curl (as shown in <FIG>), and thus attain a large fiber-to-fiber distance (spacing) <NUM>, thus effectively reducing the electromagnetic coupling between optical nanostructures <NUM> in the neighboring meta fibers <NUM>. The reduced electromagnetic coupling results in a small infrared radiation, i.e., reduced heat transport at the low humidity levels in the dry condition.

When the humidity in the environment increases, the meta fibers <NUM> straighten (as shown in <FIG>) to decrease the fiber-to-fiber spacing <NUM> between the fibers <NUM> in each yarn <NUM> to match the human radiation peak (at <NUM>), thus increasing the resonant electromagnetic (EM) coupling between the optical nanostructures <NUM> in the neighboring meta-fibers <NUM>, and thus maximizing the infrared emissivity, i.e., enhancing the heat transport at the elevated humidity levels/increased perspiration. Therefore, in response to the environmental humidity level fluctuations (dry, wet) or perspiration levels (low, high), the subject meta cooling fibers <NUM> are capable of self-regulating the heat transport by tuning the infrared emission from the subject textile <NUM> without the cost of an additional external energy usage. The subject humidity responsive self-regulation mechanism operates in a broad range of the predetermined relative humidity level, for example, from <NUM>% to <NUM>%, from <NUM>% to <NUM>%, or from <NUM>% to <NUM>%.

The scalable production of the subject meta-cooling fibers <NUM> is enabled first by a melt spinning process depicted in <FIG>. As shown in <FIG>, the system <NUM> for the subject spinning process includes a custom-designed bi-morph spinneret <NUM> which is uniquely designed (as will be detail further herein) and cooperates with a hydrophilic polymer feeder <NUM> containing a hydrophilic polymer melt <NUM>, and a hydrophobic polymer feeder <NUM> filled with the hydrophobic polymer precursor <NUM>.

The output <NUM> of the feeder <NUM> and the output <NUM> of the feeder <NUM> form the spinneret <NUM> and are used to extrude the hydrophilic polymer <NUM> and the hydrophobic polymer precursor <NUM>, respectively, in a predetermined fashion to realize alternative meta fiber configurations. Optical nanostructures <NUM>, which function to provide the optical coupling between the meta-cooling fibers <NUM>, are pre-compounded into a hydrophobic polymer precursor <NUM> in the feeder <NUM> at a predetermined concentration.

The hydrophobic polymer precursor <NUM> containing the optical nanostructures <NUM> is subsequently spun together with the hydrophilic polymer precursor <NUM> at the bi-component spinneret <NUM> to form the bi-component meta cooling fibers <NUM>, as shown in <FIG>. Subsequent to the formation of the bi-component fibers <NUM>, they are arranged in yarns <NUM>, which are wound on the yarn bobbin <NUM>. The yarns <NUM> are capable of correlation of a spatial displacement between neighboring meta fibers <NUM> in each yarn through twisting, curling, self-crimping, texturizing, hot water treatment, water vapor heating, air flowing, and their combinations.

The bi-component spinneret <NUM> is capable of spinning the polymer precursors <NUM> and <NUM>/<NUM> in two configurations, including a side-by-side configuration <NUM> shown in <FIG>, and an eccentric core-sheath configuration <NUM>, shown in <FIG>.

In the exemplary embodiment shown in <FIG>, carbon nanotubes may be chosen as the optical nanostructures <NUM> to pre-compound into the hydrophobic polymer precursor <NUM>. The melt polymer compound <NUM> and <NUM> can be disposed either side-by-side key-lock <NUM> (<FIG>), or in the eccentric sheath-core structure <NUM> depending on which structure of the spinneret <NUM> is used.

As shown in <FIG>, in order to form the side-by-side configuration <NUM>, the spinneret <NUM> is configured with the feeders <NUM>, <NUM> having a side-by-side outputs <NUM>, <NUM> from where the polymers <NUM>, <NUM> are extruded in the side-by-side fashion to form the fiber configuration <NUM>. Alternatively, as shown in <FIG>, the spinneret <NUM> is configured with the feeders <NUM>, <NUM> arranged in a co-axial configuration having their outputs <NUM>' in a surrounding relationship with the output <NUM>' to extrude the polymers <NUM>, <NUM> in the core-sheath arrangement <NUM>.

In the sheath-core structure <NUM>, the optical nanostructures containing hydrophobic polymer <NUM> constitutes the core component <NUM> embedded within the hydrophilic polymer shell <NUM>. This configuration <NUM> is beneficial in preventing the potential loss of the optical nanostructures <NUM> into the environment. The weight proportion of the core <NUM> may range, as an example, from <NUM>% to <NUM>% relative the sheath <NUM>, or from <NUM>% to <NUM>% relative the sheath <NUM>.

<FIG> depict the optical and SEM images of the cross-section of the exemplary embodiment, either in the side-by-side configuration <NUM> (in <FIG>), or in the eccentric sheath-core configuration <NUM> (in <FIG>). Although the diameter of the produced meta fibers in the example shown in <FIG> range between <NUM> and <NUM>, the diameter of the meta fibers manufactured by the subject method may range in a broad diapason, for example, from <NUM> to <NUM>, or from <NUM> to <NUM>, or from <NUM> to <NUM>.

In order to examine the carbon nanotube doping as the meta element in the subject fibers <NUM>, the eccentric sheath-core fibers <NUM> were micro-tomed and deliberately half-damaged to expose the core component <NUM> as shown in <FIG>. As best seen in <FIG>, the carbon nanotubes (optical nanostructures) <NUM> are uniformly distributed in the core component <NUM>. Such uniform distribution of the optical nanostructures <NUM> in the core component <NUM> proves that the melt spinning process does not negatively affect the incorporation of carbon nanotubes (CNTs). The Raman spectrum diagram, shown in <FIG>, further confirms the successful embedding of CNTs <NUM> in the polyethylene core component <NUM> of the produced meta cooling fibers <NUM>, exhibiting a characteristic G band at ~<NUM>-<NUM> for CNTs.

<FIG> is a photograph of the produced meta cooling fibers <NUM> with an increased dosage (<NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> ppm) of carbon nanotubes added (doped) in the hydrophobic polymer component. The color of the fibers changes (from left to right) from white to grey indicating the increasing dosage of the carbon nanotubes. Doping of the hydrophobic polymer component with carbon nanotubes does not interfere with the melt spinning process.

As an example shown in <FIG>, the fabricated meta cooling fibers can be exposed to a conventional fabric knitting process to produce either a single-jersey circular knitted fabric <NUM> (shown in <FIG>), or a double-knitted fabric <NUM> (shown in <FIG>).

Returning again to <FIG>, after the spinning, the meta fibers <NUM> are arranged in the yarns <NUM>, and are set at a straightened configuration. To re-define the "close" (or loose) state of the meta fibers at the dry conditions and the "open" (or tight) state of the meta fibers at the wet conditions, after the fiber spinning, a subsequent heat setting (training) step is performed at which the meta fibers <NUM>, either in the side-by-side configuration <NUM> or in the eccentric configuration <NUM>, are first exposed to a high humidity condition by immersing the fibers <NUM> into water. The fibers immersed into water, are mechanically twisted to define the "open" (or tight) state in the wet condition. Subsequently, as shown in <FIG>, the fibers <NUM> in the original dry/low temperatures conditions are either bent into the curved structure <NUM> (<FIG>) or curled into a spring-like structure <NUM> (<FIG>), and thermally set to define the "close" (or loose) state in the dry condition. Thus trained, when the meta fibers are exposed to fluctuating environmental conditions, the meta fibers, depending on the humidity deviation from a predetermined comfort zone, change their configuration, as "prescribed" by the heat training process, and thus modulate a spacing between the neighboring fibers, resulting in changing the EM coupling between the optical nanostructures <NUM>. The modulated EM coupling between the optical nanostructures <NUM> leads to the self- regulation of the IR emissivity to either decrease or to enhance the heat transport between the wearer's body and the environment.

As shown in <FIG>, a humidity responsive behavior is observed from a prototyped bimorph meta-cooling fibers <NUM> with an eccentric sheath-core structure arranged in a yarns <NUM>, made of <NUM>% : <NUM>% Nylon <NUM> : polyethylene. In the prototype fiber, the polyethylene component (the core) of each fiber <NUM> was hydrophobic, while the Nylon <NUM> component (sheath) was hydrophilic. Two polymers are antagonistic components, i.e., they respond differently to the environmental humidity fluctuations, causing one of the materials to expand more than the other, thus transitioning the meta fibers between the "close" and the "open" states that are defined by the heat setting step (as illustrated in <FIG>). Such humidity responsive behavior of the meta fibers <NUM> further modulates the relative disposition of neighboring meta fibers <NUM> in each yarn <NUM>, thus controlling the infrared emissivity of the smart fabrics <NUM> containing the meta fibers <NUM>.

When the environment is dry, the meta fibers curl to the "close" state to create a large distance (spacing) between each other, as shown in <FIG>, <FIG>, thus reducing the electromagnetic (EM) coupling between optical nanostructures in neighboring meta fibers <NUM>. The reduction of the EM coupling between the optical nanostructures <NUM> in the meta fibers <NUM> results in a decreased heat transport through the infrared radiation. When the environment becomes wet, the meta fibers <NUM> straighten to the "open" state to reduce the distance therebetween, as shown in <FIG>, and <FIG>, thus increasing the electromagnetic (EM) coupling between the optical nanostructures in the neighboring meta fibers <NUM>, that results in the enhanced heat transport through the infrared radiation.

The relationship between the diameter of the yarns formed from the meta fibers and the relative humidity level is presented in <FIG>.

The hydrophilic component is a polymeric material selected from a group of: Nylons, Nylon <NUM>, Nylon <NUM> (PA6), polyurethane, and their combinations.

The hydrophobic component is a polymeric material selected from a group of Polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), polybutylene terephthalate (PBT), and their combinations.

The optical nanostructures may be a nanomaterial selected from a group of single-walled carbon nanotubes, double-walled carbon nanotubes, few-walled carbon nanotubes, multi- walled carbon nanotubes, carbon nanohorns, carbon fibers, graphene, graphene oxides, carbon black, silver nanowires, copper nanowires, silicon nanowires, gold nanowires, gold nanoparticles, and their combinations.

Prototype meta fibers <NUM> have been fabricated by directly spinning two polymers <NUM>, <NUM> into a bi-component structure having either the eccentric sheath-core configuration <NUM> or the side-by-side configuration <NUM>, as shown in <FIG> and <FIG>. One of the polymer precursor is the hydrophilic precursor <NUM> with the ability to absorb and desorb the moisture. This property of the hydrophilic material <NUM> results in the volume change and the relative distance change between neighboring meta fibers <NUM> in response to the humidity fluctuations. The other polymer <NUM>, being hydrophobic, is the host for the optical nanostructures <NUM> uniformly embedded therein to enable the electromagnetic (EM) coupling between the neighboring meta fibers. In one of the implementations, CNTs are selected as the optical nanostructures that can be pre-compounded into the hydrophobic polymer <NUM> prior to the spinning. The CNTs have high electrical conductivity, chemical stability, mechanical flexibility, and textile fiber-matched length scales, and thus are good candidates for incorporation into the subject fibers <NUM>.

In the experiments illustrated, the bi-component meta fibers <NUM> were spun through a custom-made spinneret <NUM> using Nylon <NUM> as the hydrophilic component and polyethylene as the hydrophobic component. Nylon <NUM> was selected because of its ability to absorb moisture, while polyethylene was selected due to its low absorption in the infrared range. The incorporation of CNTs in the polyethylene component did not interfere with the spinning process, as was confirmed at the optical and SEM images, shown in <FIG>. Additionally, the CNTs remained uniformly distributed in polyethylene, was evident from the SEM images of the core area of an eccentric sheath-core meta fiber (<FIG>), which was further confirmed by the Raman scattering spectrum showing the characteristic G band at ~<NUM>-<NUM> for CNTs (depicted in <FIG>).

As an example, meta cooling fibers <NUM> with the eccentric sheath-core structure and various dosages of CNTs in the core component (for example, <NUM>, <NUM>, <NUM>, <NUM>, <NUM>, and <NUM> ppm) were configured into yarns <NUM> with a drawing ratio of <NUM>:<NUM> and filament number of <NUM>. The denier (unit of measurement used to determine the fiber thickness) of the produced meta fibers was changed from <NUM> to <NUM> depending on the ratio of the Nylon <NUM> and the polyethylene, as well as the rate of the spinning pump <NUM> (shown in <FIG>). The color change of the meta fibers from white to gray (as shown in <FIG>) indicates the increasing CNT dosage in the fiber.

The produced meta fibers <NUM> were arranged in the yarns <NUM>, and subsequently the yarns were knitted into the textile <NUM> with either single jersey circular knitted structure (shown in <FIG>) or double knitted structure (shown in <FIG>) with polyester fibers as the supporting base. After the spinning, the meta fibers <NUM> within the yarn <NUM> were correlated mechanically to attain the straightened configuration. Various CNT dosages (ranging from <NUM> to <NUM> ppm) were embedded in the core polymer component. The produced meta fibers were strong enough to withstand the knitting process, indicating that the mechanical strength of the meta fibers was not reduced by adding the CNTs.

To provide the self-regulation of the infrared emission in the meta fibers to result in the active modulation of heat transfer from the human body (garment wearer) to the environment in response to humidity level fluctuations, two states of meta fibers were defined:.

In the "close" state of the meta fibers, the electromagnetic coupling between the neighboring meta fibers is minimized, due to an increased distance <NUM> between the fibers <NUM>. This configuration results in a reduced heat transfer from a wearer's body to the environment, which is beneficial in a dry and/or cold situation.

To the contrary, in the "open" state of the meta fibers, the electromagnetic coupling between the neighboring meta fibers <NUM> is maximized due to a smaller fiber-to-fiber distance <NUM> (matching the infrared radiation wavelength), thus resulting in an enhanced heat transfer from the wearer's body to the environment, which is beneficial in a wet and/or hot condition.

To "train" the fibers, i.e., to define the "close" state of the meta fibers at the dry (and/or cold) condition and the "open" state of the meta fibers at the wet (and/or hot) condition, a subsequent heat setting step is performed, as illustrated in <FIG>. Specifically, after the spinning step, the meta fibers <NUM> were first twisted in water to define the "open" state in the wet condition, so that they could be either bent into a curved configuration <NUM> or curled into a spring-like configuration <NUM>, shown in <FIG>, respectively. The fibers also were heat-set to define the "close" state in the dry condition (without water). The "close" state of said meta fiber was established by heat setting the meta fiber in a dry condition with the relative humidity level lower than <NUM>%, and with heat setting temperature ranging between <NUM> and <NUM>.

In an exemplified demonstration, <NUM>-filament meta yarns using Nylon <NUM> and polyethylene with eccentric sheath-core structure were treated (trained) to establish the "open" and "close" states. After the treatment (training), the meta yarns <NUM> demonstrated a large yarn diameter being exposed to a low humidity of <NUM>%, but shrank to a smaller yarn diameter when the humidity was increased to <NUM>%. Specifically, the functionality of the subject meta fibers is sufficient at predetermined relative humidity levels ranging from <NUM>% to <NUM>%, from <NUM>% to <NUM>%, and from <NUM>% to <NUM>%. The yarn diameter fluctuations though contracting or expanding of the yarns responsive to the humidity level variations, and/or due to the sweat, is reversible with multiple humidity change cycles, proving a dynamic actuation of the produced meta fibers.

Claim 1:
A textile composed of meta fibers, comprising:
a plurality of meta fibers arranged into a yarn, each of said meta fibers including:
a hydrophobic component of a first spinnable polymer material, wherein the hydrophobic component is a polymeric material selected from a group consisting of: Polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), polybutylene terephthalate (PBT), and combinations thereof;
a hydrophilic component of a second spinnable polymer material, wherein the hydrophilic component is a polymeric material selected from a group consisting of: Nylons, Nylon <NUM>, Nylon <NUM> (PA6), polyurethane, and combinations thereof; and
a plurality of optical nanostructures embedded in said hydrophobic component;
wherein said hydrophobic component and the hydrophilic component are connected in a configuration selected from a group including an eccentric sheath-core configuration, and side-by-side configuration, wherein in said eccentric sheath-core configuration, said hydrophobic component constitutes a core, and said hydrophilic component constitutes a sheath surrounding said core; and
wherein, responsive to fluctuations in a relative humidity level, each said meta fiber changes a configuration thereof, resulting in modulation of a fiber-to-fiber spacing within the yarn, thus changing an electromagnetic coupling between the optical nanostructures embedded in said fibers, resulting in the infrared optical emission adjustment, followed by an active self-regulation of the air movement and heat transport through the smart textile composed of said meta fibers.