阅读说明：本技术 用于被动辐射式室外个人降温的光谱选择性纺织品 (Spectrally selective textiles for passive radiative outdoor personal cooling ) 是由 崔屹 范汕洄 蔡丽丽 亚历克斯·Y·宋 李炜 徐伯均 于 2019-02-04 设计创作，主要内容包括：一种纺织品,其包括：(1)基质；以及(2)分散在所述基质中的颗粒填料。所述纺织品的在9.5μm的波长处的红外辐射的透射率为至少约40％,并且所述纺织品的在0.3μm至2μm的波长范围内的辐射的加权平均反射率为至少约40％。(A textile, comprising: (1) a substrate; and (2) a particulate filler dispersed in the matrix. The textile has a transmittance of infrared radiation at a wavelength of 9.5 μm of at least about 40% and a weighted average reflectance of radiation within a wavelength range of 0.3 μm to 2 μm of at least about 40%.)

1. A textile, comprising:

a substrate; and

a particulate filler dispersed in the matrix,

wherein the textile has a transmittance of infrared radiation at a wavelength of 9.5 μm of at least 40%, and

wherein the textile has a weighted average reflectance of at least 40% of radiation in the wavelength range of 0.3 μm to 2 μm.

2. The textile according to claim 1, wherein the substrate comprises at least one polyolefin.

3. The textile of claim 2, wherein the substrate comprises at least one of polyethylene or polypropylene.

4. The textile according to claim 1, wherein the peak particle size of the particulate filler is in the range of 10 nm to 4000 nm.

5. The textile of claim 1, wherein the particulate filler comprises an inorganic material.

6. The textile of claim 5, wherein the particulate filler includes at least one of a metal oxide, a metal halide, or a metal sulfide.

7. The textile of claim 5, wherein the particulate filler comprises at least one of zinc oxide, potassium bromide, cesium iodide, potassium chloride, sodium chloride, or zinc sulfide.

8. The textile according to claim 1, wherein the difference in refractive index between the particulate filler and the matrix is at least ± 5% relative to the refractive index of the matrix.

9. A textile according to claim 1 wherein the transmission of infrared radiation at a wavelength of 9.5 μ ι η is at least 60%.

10. A textile according to claim 1 wherein the weighted average reflectance of radiation in the wavelength range of 0.3 to 2 μ ι η is at least 60%.

11. The textile according to claim 1, wherein the substrate is porous.

12. The textile according to claim 11, wherein the volume percentage of pores within the matrix is at least 5%.

13. The textile according to claim 11, wherein the pores within the matrix have a peak pore size in the range of 10 nm to 4000 nm.

14. The textile according to claim 1 comprising fibers including the matrix and the particulate filler dispersed within the matrix.

15. The textile according to claim 1 comprising a film comprising the matrix and particulate filler dispersed within the matrix.

16. A textile, comprising:

a substrate; and

a particulate filler dispersed in the matrix,

wherein the textile has a transmittance of infrared radiation at a wavelength of 9.5 μm of at least 40%, and

wherein the textile has a peak in reflectance at a wavelength in the visible range corresponding to a particular color.

17. The textile of claim 16, wherein the particulate filler comprises at least one of a metalloid, a metal oxide, or a metal cyanide.

18. A method of regulating the temperature of a human body, comprising:

placing the textile of any of claims 1-17 in proximity to the human body.

19. A method of forming a porous textile, comprising:

forming a mixture of a solvent, at least one polymer, and a particulate filler, wherein the particulate filler comprises an inorganic material having a transmittance of infrared radiation of at least 40% at a wavelength of 9.5 μ ι η and a peak particle size of the particulate filler is in a range of 10 nm to 4000 nm;

extruding the mixture to form a textile comprising a solvent and the particulate filler dispersed within the textile; and

extracting a solvent from the textile to form the porous textile.

20. The method of claim 19, wherein the at least one polymer comprises a polyolefin.

21. The method of claim 19, wherein the particulate filler comprises at least one of zinc oxide, potassium bromide, cesium iodide, potassium chloride, sodium chloride, or zinc sulfide.

Background

Outdoor heat stress poses a serious threat to public health and limits industrial labor supply and productivity, thereby adversely affecting social health and economics. However, there is a lack of an effective and economical method that can provide localized outdoor body cooling without being constrained by humidity and wind levels.

In this context, it is desirable to develop embodiments of the present disclosure.

SUMMARY

In some embodiments, a textile (textile) comprises: (1) a substrate; and (2) a particulate filler dispersed in the matrix. The textile has a transmittance (transmission) of infrared radiation at a wavelength of 9.5 μm of at least about 40% and a weighted average reflectance of radiation within a wavelength range of 0.3 μm to 2 μm of the textile is at least about 40%.

In some embodiments of the textile, the substrate comprises at least one polyolefin.

In some embodiments of the textile, the substrate comprises at least one of polyethylene or polypropylene.

In some embodiments of the textile, the particulate filler has a peak particle size in the range of about 10 nm to about 4000 nm.

In some embodiments of the textile, the particulate filler comprises an inorganic material.

In some embodiments of the textile, the particulate filler comprises at least one of a metal oxide, a metal halide, or a metal sulfide.

In some embodiments of the textile, the particulate filler comprises at least one of zinc oxide, potassium bromide, cesium iodide, potassium chloride, sodium chloride, or zinc sulfide.

In some embodiments of the textile, the difference in refractive index between the particulate filler and the matrix is at least about ± 5% relative to the refractive index of the matrix.

In some embodiments of the textile, the transmittance of infrared radiation at a wavelength of 9.5 μm is at least about 60%.

In some embodiments of the textile, the weighted average reflectance of radiation in the wavelength range of 0.3 μm to 2 μm is at least about 60%.

In some embodiments of the textile, the substrate is porous.

In some embodiments of the textile, the volume percentage of pores within the matrix is at least about 5%.

In some embodiments of the textile, the pores within the matrix have a peak pore size in the range of about 10 nm to about 4000 nm.

In some embodiments of the textile, the textile comprises fibers comprising a matrix and a particulate filler dispersed within the matrix.

In some embodiments of the textile, the textile comprises a film comprising a matrix and a particulate filler dispersed within the matrix.

In further embodiments, a textile comprises: (1) a substrate; (2) a particulate filler dispersed in the matrix. The textile has a transmittance of infrared radiation at a wavelength of 9.5 μm of at least about 40% and the textile has a peak in reflectance at a wavelength in the visible range corresponding to the particular color.

In some embodiments of the textile, the particulate filler comprises at least one of a metalloid (metalloid), a metal oxide, or a metal cyanide.

In a further embodiment, a method of regulating the temperature of a human body comprises placing the textile of any of the preceding embodiments in proximity to a human body.

In a further embodiment, a method of forming a porous textile comprises: (1) forming a mixture of a solvent, at least one polymer, and a particulate filler, wherein the particulate filler comprises an inorganic material having a transmittance of infrared radiation of at least about 40% at a wavelength of 9.5 μ ι η and a peak particle size of the particulate filler in a range of 10 nm to 4000 nm; (2) extruding the mixture to form a textile comprising a solvent and a particulate filler dispersed within the textile; and (3) extracting the solvent from the textile to form a porous textile.

In some embodiments of the method, the at least one polymer comprises a polyolefin.

In some embodiments of the method, the particulate filler comprises at least one of zinc oxide, potassium bromide, cesium iodide, potassium chloride, sodium chloride, or zinc sulfide.

Other aspects and embodiments of the disclosure are also contemplated. The foregoing summary and the following detailed description are not intended to limit the disclosure to any particular embodiment, but are merely intended to describe some embodiments of the disclosure.

Drawings

For a better understanding of the nature and objects of some embodiments of the present disclosure, reference should be made to the following detailed description taken in conjunction with the accompanying drawings.

FIG. 1 (a). Schematic of a porous membrane of some embodiments.

FIG. 1 (b). Schematic of non-porous films of some embodiments.

Fig. 2. Schematic illustrations of (a) a woven textile, (b) porous polymeric fibers, and (c) non-porous polymeric fibers of some embodiments.

Fig. 3. (a) A schematic diagram illustrating the heat input and output paths of a human body under sunlight in an outdoor environment is shown. (b) Schematic representation of a nanoporous Polyethylene (PE) textile embedded with zinc oxide (ZnO) nanoparticles designed for radiative outdoor cooling by reflecting sunlight and transmitting human thermal radiation. (c) Spectral comparison of AM 1.5G solar radiation and human thermal radiation simulated using planck's law at skin temperatures of about 34 ℃ shows that they have marginal (marginal) overlap in the wavelength range.

Fig. 4. (a) Standardized scattering cross-section simulation of individual ZnO particles in polyethylene medium with wavelength range 0.4-16 μm, particle diameter varying from 0.01 to 10 μm. (b) Comparison of normalized scattering cross-sections between ZnO particles and pores having the same diameter of 320 nm in polyethylene media. Dependence of (c) solar reflection and (d) mid-infrared transmission of the plurality of ZnO particles embedded in the nanoporous polyethylene on the size and density of the ZnO particles. For each data point in (c) and (d), the scattering cross-sections are averaged with a normal distribution of particle sizes with a variance of ± 0.1 μm. The solar reflection is averaged over a spectral range of solar irradiance of 0.4 to 4 μm. The mid-infrared transmission is averaged over a human thermal radiation wavelength range of 4 to 16 μm. (e) Projecting the three-dimensional maps in (c) and (d) on a density and size plane. The white fraction presents the optimum density and size of the ZnO particles in which high solar reflection and high mid-infrared transmission can be achieved.

Fig. 5. (a) And (3) an image of the ZnO-PE textile in sunlight. (b) Side and top views of X-ray computed tomography images of ZnO-PE samples show a substantially uniform distribution of ZnO particles. The inset is a distribution plot of the ZnO particle diameter, measured using dynamic light scattering, which peaks at about 500 nm. (c) An image of a roll of ZnO-PE fiber made by melt extrusion (melt-extrusion). Scanning Electron Microscope (SEM) images show (d) the upper surface and (e) the cross-section of the ZnO — PE thin film sample. (f) High magnification SEM images show the morphology of individual ZnO particles. (g) Reflectance and transmittance spectra of ZnO-PE in the ultraviolet to mid-infrared range (about 0.3 to about 16 μm) as measured by integrating spheres (integrating spheres). The shaded area shows the AM 1.5G solar spectrum (left) and the human body radiation spectrum (right) for reference.

Fig. 6. (a) Images of thermal measurement devices in an outdoor test environment. (b) Schematic representation of a thermal measurement device comprising a heater simulating skin, a thermocouple measuring the temperature of the simulated skin, and a textile sample covering the simulated skin. (c) The temperatures measured with ZnO-PE cover, cotton cover, and bare simulated skin warmer under wind convection were compared over a period of about four hours in a sunny spring, stanford, ca. Ambient temperature and solar irradiance were measured and plotted for reference. (d) Calculating the additional cooling power requirement for maintaining normal skin temperature at about 34 ℃ with ZnO-PE covered, cotton covered and bare simulated skin heaters according to the measurement result in (c). (e) The temperatures measured with ZnO-PE covered, cotton covered and bare simulated skin warmer under wind convection and sweat evaporation were compared. (f) Comparing the cooling power demand at 13:00 for ZnO-PE covered, cotton covered and bare simulated skin warmer in (d) with the cooling power provided by sweat evaporation, the cooling power was estimated as the product of the water evaporation rate through the textile (fig. 12) and the heat of evaporation of water.

Fig. 7. Ultraviolet-visible-near infrared (UV-VIS-NIR) reflectance and Fourier Transform Infrared (FTIR) emissivity of human skin.

Fig. 8. UV-VIS-NIR reflectance and FTIR transmittance of cotton.

Fig. 9. Comparison of measured (solid line) and simulated (dashed line) reflectance and transmittance spectra of ZnO-PE from the ultraviolet to the mid-infrared range (0.3-16 μm). The following parameters were assumed for the simulation to closely match the experimental values: average air pore diameter of 200nm, porosity of 20%, ZnO: the PE mass ratio is 2: and 5, the normal distribution of the diameters of ZnO particles is d = 0.5 μm +/-0.1 μm, and the thickness of the film is 150 μm. The shaded area shows the AM 1.5G solar spectrum (left) and the human body radiation spectrum (right) for reference.

Fig. 10. The skin temperature of a simulated skin warmer not covered by the textile in sunlight and shadow was measured.

Fig. 11. Schematic representation of a heat transfer model in sunlight for a human body wearing a garment.

Fig. 12. Skin temperature calculated from heat transfer model analysis was compared to measurements of cotton and ZnO-PE covered skin.

FIG. 13. Water evaporation rate of ZnO-PE covered skin, cotton covered skin and bare skin.

Fig. 14. The effect of the ZnO-PE layer thickness on (a) solar reflection and (b) mid-infrared transmission. As the thickness of the nanocomposite layer increases, a compromise is observed in which a thickness of about 80 μm to about 160 μm is optimal for both high solar reflection and mid-infrared transmission.

Fig. 15. Inductively coupled plasma mass spectrometry (ICP-MS) measurements to quantify Zn in water before and after washing ZnO-PE textile material with detergent and stirring for about 30 minutes²⁺And (4) concentration. The results show that trace amounts of ZnO (about 2 parts per billion (ppb)) are released into the water during the washing process. The good durability of the embedded structure is demonstrated due to the tight wrapping of PE on the ZnO particles.

Fig. 16. Of textile samples dissolved in chloroform-d¹H Nuclear Magnetic Resonance (NMR) spectrum (upper panel) to detect residual dichloromethane in the sample. Bottom curve from chloroform-d (for¹Solvent for H NMR measurement) as a blank. The peak at about 7.26 ppm corresponds to chloroform-d. The water peak at about 1.56 ppm is due to absorption of trace amounts of moisture from the atmosphere. The peak position of methylene chloride should be at about 5.3 ppm, which is not present in the sample curve. These measurements confirm that methylene chloride is very volatile and can be substantially completely removed by evaporation. After drying in air for about 2 hours, no residual methylene chloride was detected from the textile samples.

Fig. 17. The black color is achieved by adding micron-sized silicon particles in polyethylene, which also shows high infrared transparency in the wavelength range of about 4 to about 18 μm. (a) A black Si-PE composite film is shown. (b) Black Si-PE fibers are shown along with other colored polyethylene fibers. (c) Infrared transmission spectrum of the Si-PE composite film.

Fig. 18. (a) Schematic design of radiant cooling textile coloration by mixing IR transparent inorganic pigment nanoparticles with PE. The mixed composite can then be extruded into continuous fibers to be woven into interwoven textiles by large scale industrial processes. Photo (b) and FTIR absorption spectra (c) of selected inorganic pigment powders. (d) Prussian Blue (PB), (e) iron oxide (Fe)₂O₃) And (f) SEM images of silicon (Si) nanoparticles.

Fig. 19. A photograph of (a), a UV-VIS reflectance, (c) a FTIR transmittance, and (d) a visible opacity spectrum of a pigment nanoparticle mixed polyethylene composite film.

Fig. 20. (a) Photographs of three colored polyethylene fiber spools produced by industrial extrusion. (b) Tensile strength (tensile strength) tests have shown that colored polyethylene fibers have a tensile strength comparable to cotton. (c) Blue PB-PE, (d) Red Fe₂O₃-optical micrographs of extruded fibers of PE and (e) yellow Si-PE. (f-h) optical micrographs show the weave pattern, (i-k) photographs of woven textiles with good abrasion resistance.

FIG. 21. (a) The total FTIR transmittance of the colored polyethylene textile was measured. (b) A graph showing the negligible (ppb level) increase in the concentration of each metal ion in water after washing colored polyethylene textiles. (c) The temperatures measured by the bare and textile covered skin analog heaters were compared. The textile samples comprise cotton, PB-PE and Fe₂O₃-PE, Si-PE and nanoporous polyethylene (nanoPE). (d) Bare skin and cotton, PB-PE, Fe₂O₃-infrared images of human skin covered by PE and Si-PE textiles.

Description of the invention

Embodiments of the present disclosure are directed to spectrally selective textiles. In some embodiments, a solar reflective, Infrared (IR) transparent, particle-embedded polymeric textile is provided for outdoor wearers that achieve cooling performance in direct sunlight in outdoor environments to maintain thermal comfort.

Heat exchange between the human body and the outdoor environment involves conduction, convection, evaporation and radiation. Thus, maintaining outdoor thermal comfort involves reducing thermal stress by reducing heat acquisition and increasing heat loss. Other approaches have focused primarily on evaporative and convective heat losses from the garment to achieve cooling outdoors, but both of these heat dissipation paths have their own constraints which depend largely on environmental conditions such as humidity and wind levels. Although solar irradiance and thermal radiation paths contribute greatly to overall heat exchange, they have not been fully considered for outdoor textiles. Unlike ordinary textiles, IR transparent textiles reflect a high percentage of sunlight, while the absorption of IR by the human body is low, thereby simultaneously reducing the input and increasing the output of radiant heat transfer without additional energy consumption, resulting in a cooler wearer's feel in an outdoor environment. In addition, the polymer composite may be formed into fibers by extrusion, and a woven textile may be formed from the fibers by weaving, thereby providing comfort and breathability as a near-skin textile. Therefore, the textile is suitable for mass production. As such, embodiments of the present disclosure provide a sunlight-reflective, IR-transparent textile for outdoor personal cooling that maintains the comfort of near-skin textiles and can also be achieved on a large scale.

The IR transparent textile of some embodiments has low absorption of IR radiation emitted by the human body, which can therefore be freely transmitted into the environment and cause the wearer to feel cooler. Meanwhile, the textile is provided with the particle filler dispersed in the textile, and the particle filler is used for scattering sunlight irradiance spectrum, so that a cooling effect is provided under direct sunlight. Additionally, the textile may be porous, and the pores in the textile may make the textile breathable and increase heat dissipation by conduction and convection. The textile may be formed as a porous film embedded with a particulate filler, or may be formed as a woven structure based on fibers. Polymeric fibers having pores and embedded with particulate fillers can be formed on a large scale by methods such as extrusion and solvent extraction, and woven textiles can be formed on a large scale from such fibers by methods such as weaving.

The textile of some embodiments includes a single polymer or a mixture of two or more different polymers. In some embodiments, to impart IR transparency, a polymer or mixture of polymers with low IR radiation absorption may be used, for example, low radiation absorption in the mid IR range of about 4 μm to about 20 μm or about 4 μm to about 16 μm. In such embodiments, suitable polymers include polyolefins, such as Polyethylene (PE), polypropylene (PP), and other thermoplastic polyolefins or polyolefin elastomers. For PE, suitable molecular weight ranges may be low density PE (ldpe), high density PE (hdpe), and ultra high molecular weight PE (uhmwpe). PE may be blended with or at least partially replaced by other polymers such as PP, polyvinyl chloride (PVC), vinylon (vinylon), Polyacrylonitrile (PAN), polyamides (e.g., nylon), polyethylene terephthalate (PET), polyesters, polyvinyl fluoride (PVF), copolymers, other thermoplastic polymers, natural polymers, and the like. Other polymers that may be used in place of or in combination with the polyolefin have low IR radiation absorption, such as polymers that are substantially free of one or more of the following functional groups: C-O, C ‒ N, aromatic C ‒ H, and S = O, and polymers such as having a content of one or more of these functional groups of no greater than about 1 mmol/g, no greater than about 0.1 mmol/g, no greater than about 0.01 mmol/g, no greater than about 0.001 mmol/g, or no greater than about 0.0001 mmol/g. In some embodiments, suitable polymers have a transmittance of IR radiation at a wavelength of 9.5 μm of at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, or at least about 80%, and up to about 90%, up to about 95%, up to about 98%, or more. In some embodiments, suitable polymers have a weighted average transmission of IR radiation in the 7-14 μm wavelength range of at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, or at least about 80%, and up to about 90%, up to about 95%, or more. One or more additives may be included in the textile forming process, such as antioxidants, antimicrobials, colorants or dyes, water absorbers (e.g., cotton), metals, wood, silk, wool, and the like. One or more additives may be dispersed in the polymer or mixture of polymers contained in the textile.

The textile of some embodiments also includes a particulate filler dispersed in the polymer or mixture of polymers. The particulate filler provides a contrast in refractive index with respect to the polymer or polymer mixture comprised in the textile to selectively scatter light in the desired spectrum, especially strongly in the desired spectrum, but with little scattering in the mid-IR range. In some embodiments, the particulate filler is sized and has a material composition to selectively scatter light in the solar irradiance spectrum in the range of about 300 nm to about 4 μm, including radiation in the visible range of about 400 nm to about 700nm and radiation in the near IR range of 700nm to about 4 μm, to provide a cooling effect in direct sunlight. In other embodiments, the particulate filler is sized and has a material composition to selectively scatter certain wavelengths or colors in the visible range to provide a coloring effect. For example, the particulate filler (and textiles including such fillers) may have a peak in reflectance at a particular wavelength (e.g., about 450 nm) within the visible range corresponding to a particular color, thereby producing a visual presentation of that particular color (e.g., blue), or may have a peak in reflectance at another particular wavelength (e.g., about 600 nm) within the visible range corresponding to another particular color, thereby producing a visual presentation of that other particular color (e.g., yellow), or may have a peak in reflectance at another particular wavelength (e.g., about 750 nm) within the visible range corresponding to another particular color, thereby producing a visual presentation of that other particular color (e.g., red), and so forth.

In some embodiments, the relative difference in refractive index between the particulate filler and the polymer or mixture of polymers is at least about ± 1%, e.g., at least about ± 5%, at least about ± 8%, at least about ± 10%, at least about ± 15%, at least about ± 20%, at least about ± 25%, at least about ± 30%, at least about ± 35%, at least about ± 40%, at least about ± 45%, or at least about ± 50% relative to the refractive index of the polymer or mixture of polymers included in the textile (e.g., for visible light measured at 589 nm). In some embodiments, the absolute difference in refractive index between the particulate filler and the polymer or mixture of polymers is at least about ± 0.01, such as, for example, at least about ± 0.05, at least about ± 0.1, at least about ± 0.15, at least about ± 0.2, at least about ± 0.25, at least about ± 0.3, at least about ± 0.35, at least about ± 0.4, at least about ± 0.45, at least about ± 0.5, or at least about ± 0.55, relative to the refractive index of the polymer or mixture of polymers included in the textile (e.g., for visible light measured at 589 nm). The refractive index of the particulate filler may be higher or lower than the refractive index of the polymer or mixture of polymers comprised in the textile.

Examples of suitable materials for the filler include inorganic materials having low absorption to radiation in the range of about 300 nm to about 20 μm (including radiation in the visible range, radiation in the near IR range, and radiation in the mid IR range), for example, metalloids (e.g., silicon), metal oxides (e.g., zinc oxide and iron oxide), metal halides (e.g., potassium bromide, cesium iodide, potassium chloride, and sodium chloride), metal sulfides (e.g., zinc sulfide), metal cyanides (e.g., prussian blue), and the like. In some embodiments, suitable materials for the filler have a transmittance of IR radiation at a wavelength of 9.5 μm of at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, or at least about 80%, and up to about 90%, up to about 95%, up to about 98%, or more. In some embodiments, suitable materials for the filler have a weighted average transmission of IR radiation at wavelengths of 7-14 μm of at least about 30%, at least about 40%, at least about 50%, at least about 60%About 70%, or at least about 80%, and up to about 90%, up to about 95%, or more. The filler is sized to scatter radiation primarily in the visible and near IR ranges rather than in the mid IR range. For example, the filler may be nano-sized (e.g., as nanoparticles) so as to be comparable to the wavelength of visible light and lower than the wavelength of mid-IR radiation. In some embodiments, the average or peak particle size of the filler is in the range of about 10 nm to about 4000nm, about 1000 nm to about 4000nm, about 100 nm to about 1000 nm, about 100 nm to about 900 nm, about 100 nm to about 800 nm, about 100 nm to about 700nm, about 100 nm to about 600 nm, about 100 to about 500 nm, about 100 nm to about 400 nm, about 100 nm to about 300 nm, about 500 nm and about 1000 nm, about 200nm and about 900 nm, about 300 nm and about 800 nm, about 400 nm and about 700nm, or about 400 nm and about 600 nm, although larger or smaller fillers are also contemplated. In some embodiments, the distribution of particle sizes may be controlled to impart a desired wavelength of scattered radiation. For example, the size of the filler can be relatively uniform, such as where the standard deviation of the particle size is no greater than about 50%, no greater than about 45%, no greater than about 40%, no greater than about 35%, no greater than about 30%, no greater than about 25%, or no greater than about 20% of the average particle size. In some embodiments, the number density of the filler within the textile is at least about 0.1 μm^-3At least about 0.5 μm^-3At least about 1 μm^-3At least about 2 μm^-3At least about 4 μm^-3Or at least about 6 μm^-3And up to about 8 μm^-3Or larger. The filler may be regular or irregular in shape and may have an aspect ratio of about 3 or less or greater than about 3.

The textile of some embodiments is porous. The pores of the textile may be sized to help selectively scatter light in a desired spectrum, along with the filler. For example, the holes may be nano-sized (e.g., as nano-holes) so as to be comparable to the wavelength of visible light and lower than the wavelength of mid-IR radiation. In some embodiments, the average or peak pore size of the pores is in the range of about 10 nm to about 4000nm, about 1000 nm to about 4000nm, about 100 nm to about 1000 nm, about 100 nm to about 900 nm, about 100 nm to about 800 nm, about 100 nm to about 700nm, about 100 nm to about 600 nm, about 100 to about 500 nm, about 100 nm to about 400 nm, about 100 nm to about 300 nm, about 500 nm and about 1000 nm, about 200nm and about 900 nm, about 300 nm and about 800 nm, about 400 nm and about 700nm, or about 400 nm and about 600 nm, although larger or smaller pores are also contemplated. In some embodiments, the distribution of pore sizes may be controlled to impart a desired wavelength of scattered radiation. For example, the size of the pores can be relatively uniform, such as where the standard deviation of the pore size is no greater than about 50%, no greater than about 45%, no greater than about 40%, no greater than about 35%, no greater than about 30%, no greater than about 25%, or no greater than about 20% of the average pore size. The pore size can be determined using, for example, the Barret-Joyner-Halenda model. In some embodiments, the volume percentage of pores within the textile is at least about 1%, at least about 5%, at least about 10%, at least about 15%, or at least about 20%, and up to about 30% or more. In some embodiments, at least some of the pores may be interconnected to increase breathability and increase conductive and convective heat dissipation through the interconnected pores. The pores may be regular or irregular in shape and may have an aspect ratio of about 3 or less or greater than about 3.

The textile of some embodiments may be formed as a porous film 100 comprising a matrix 102 of a polymer or mixture of polymers having pores 104 and embedded particulate fillers 106 (see fig. 1 (a)), or may be formed as a non-porous film 110 comprising a matrix 112 of a polymer or mixture of polymers and embedded particulate fillers 116 (see fig. 1 (b)). Additional embodiments of the textile may be formed as a fiber-based woven textile 200 (see fig. 2 (a)). In the case of woven textile 200, the porous polymeric fibers 202 included in textile 200 include an elongated member 204 having pores 206, and a particulate filler 208 dispersed within the elongated member 204. Alternatively or in combination, the non-porous polymeric fibers 212 included in the textile 200 include elongated members 214 that are free of pores, and particulate fillers 218 dispersed within the elongated members 214. In general, the polymer fibers can have a circular cross-sectional shape, as well as various other regular or irregular cross-sectional shapes, such as multi-lobal, octagonal, oval, pentagonal, rectangular, square, trapezoidal, triangular, wedge-shaped, and the like. The surface of the fiber may be chemically or physically modified to impart other properties, such as hydrophilicity, antimicrobial properties, coloration, texture, and the like. For example, a coating may be applied on the surface of the fiber to impart hydrophilicity, such as a coating of a hydrophilic agent. In some embodiments, the polymer fiber includes a plurality (e.g., two or more) of elongate members that are connected or otherwise combined to form an entirety of the fiber. At least one of the elongate members comprises a particulate filler dispersed therein, and the elongate members may comprise the same polymer (or same mixture of polymers) or a different polymer (or different mixture of polymers). The elongated members may be arranged in a variety of configurations. For example, the elongate members may be arranged in a core-sheath (core-sheath) configuration, an island-in-sea (island-in-sea) configuration, a matrix or checkerboard configuration, a segmented-pie (segmented-pie) configuration, a side-by-side (stripe) configuration, a striated (striped) configuration, or the like. Other embodiments of the polymer fiber may be implemented to have a hollow structure (hollow structure), a block structure (block structure), a grafted structure (grafted structure), and the like.

In some embodiments, the textile is formed by a process of extrusion and solvent extraction. In particular, the polymer or mixture of polymers may be combined with the particulate filler in a solvent such as paraffin oil to form a mixture. The volume percent of solvent in the mixture can be selected to obtain a desired volume percent of pores in the resulting textile after solvent extraction, e.g., at least about 1%, at least about 5%, at least about 10%, at least about 15%, or at least about 20%, and up to about 30% or more. Other suitable liquid solvents or solids, such as solid waxes, mineral oils, and the like, may be used instead of or in combination with the paraffinic oil. Also, one or more additives, such as water-absorbing agents, colorants, and the like, may be included in the mixture. The mixture may then be extruded through an extrusion device to form a film or polymer fiber including the solvent dispersed therein, and the solvent is extracted to leave the nanopores. The extraction of the solvent may be carried out by immersion in a chemical bath of an extracting agent (e.g. dichloromethane), but other extraction means, such as evaporation, are contemplated. Once formed, the polymer fibers of some embodiments may be subjected to various processes to form a woven textile as individual fibers or as included in a multi-fiber yarn. Examples include weaving, knitting, felting, braiding, knitting, and the like. In some embodiments, polymer fibers comprising different particulate fillers to produce different colors are combined or mixed in specific ratios to form a woven textile having a desired color.

The textile of some embodiments may exhibit a variety of benefits. In some embodiments, the textile has a transmittance of IR radiation at a wavelength of 9.5 μm of at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, or at least about 80%, and up to about 90%, up to about 95%, up to about 98%, or more. In some embodiments, the textile has a weighted average transmission of IR radiation in the wavelength range of 7-14 μm of at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, or at least about 80%, and up to about 90%, up to about 95%, or more. In some embodiments, the weighted average reflectance of the textile for radiation in the wavelength range of 0.3-2 μm is at least about 30%, at least about 40%, at least about 50%, at least about 60%, at least about 70%, or at least about 80%, and up to about 90%, up to about 95%, up to about 98%, or more.

The textile of some embodiments may be incorporated into a cloth as a single layer of a single layer cloth or multiple layers (e.g., two or more layers) of a multiple layer cloth. In the case of a multi-layer cloth, the textile may be laminated or otherwise combined with one or more additional layers, such as one or more layers of other textile materials (e.g., cotton or polyester). The resulting cloth can be used for a variety of articles of apparel (e.g., apparel and footwear), as well as other products (e.g., medical products).

Examples

The following examples describe certain aspects of some embodiments of the present disclosure to illustrate and provide a description to those of ordinary skill in the art. The examples should not be construed as limiting the disclosure, as they merely provide specific methods that can be used to understand and practice some embodiments of the disclosure.