Preparation Of Super-hydrophobic And UV-blocking Multifunctional Textiles Based On Porous Materials

Inspired by superhydrophobic phenomena in nature,superhydrophobic surfaces have attracted more focus from many scholars and experts,and its preparation techniques and methods are constantly being updated and developed.Learning from the lotus effect,micro-nano rough structure and low surface energy material are two essential conditions for constructing superhydrophobic surfaces.Micro-nano roughness structure is often achieved through the introduction of nano-inorganic materials.Both Si O₂ aerogels and flower-like Cu S are nanoporous materials and are capable of building micro-nano-roughness structures on textile surfaces.Si O₂ aerogel has the characteristics of small density,large specific surface area and three-dimensional network porous structure showing a broad application prospect in the super-hydrophobic surface construction.Due to its unique flower-like hierarchical porous structure and photoelectric effect,flower-like Cu S not only provides surface roughness for textiles,but also imparts ultraviolet and photocatalytic properties for textiles.It is a great practical significance for the development and application of multifunctional textiles.The organic-inorganic composite structure is constructed on the surface of the cotton fabric through the combination of Si O₂ aerogels nanoporous material and flower-like Cu S hierarchical porous structure with low surface energy material.It not only enables textiles to have superhydrophobic and UV functionalities,but also enhances the bonding of inorganic materials and textiles and their durability.It is of great importance for the research and development of durable multifunctional textiles.In this paper,based on nano-porous materialsl,according to the principle of"lotus leaf effect"and the superhydrophobic model,superhydrophobic and UV-resistant multi-functional textiles were prepared by organic-inorganic composites.The major studies included:?1?Hydrophobic Si O₂ aerogels were prepared by using methyltrimethoxysilane?MTMS?as precursor,sol-gel method and atmospheric drying.The effects of molar ratio of MTMS/Me O H,p H,molar ratio of oxalic acid to MTMS,gelation temperature and aging temperature on the density and porosity of hydrophobic aerogels were studied.The best preparation technology of hydrophobic aerogels was obtained.The results showed that when the molar ratio of MTMS to Me OH was 1:24,the p H value of aqueous ammonia was adjusted to 8,the molar ratio of oxalic acid/MTMS was 1.6×10^-4:1,the gelation temperature was 40?and the aging temperature was 50?,the gel time of the prepared aerogels was 9h,the density was 0.1064g/cm³,the porosity was 95.16%,the specific surface area was 394.03m²/g,and the pore size was mainly distributed in the range of 2?10nm.Infrared spectrum?FT-IR?showed that the prepared aerogels had more methyl groups with less hydroxyl groups,which was consistent with that of the aerogels.The water contact angle reached 151.0°.From the SEM images,it can be seen that the porous structure of the three-dimensional space network of the Si O₂ aerogels had a particle size of about 2?m and the pore sizes were mostly micro-nano.?2?The PDMS/Si O₂ aerogels composite material was prepared by mixing the aerogels prepared under the optimum conditions and the polydimethylsiloxane?PDMS?by the one-step method.Through the dipping-padding-curing process,super-hydrophobic cotton fabric was obtained.The effects of various factors on the hydrophobic effect of cotton fabrics after finishing were discussed.The results showed that:when the amount of Si O₂ aerogels was 4%,the amount of PDMS was 4%,the curing temperature was 160?,the curing time was 60min,the water contact angle of the prepared cotton fabric was155.6°and the rolling angle was 8.2°,with excellent super-hydrophobic properties.FT-IR and XPS showed that the surface of the finished cotton fabric had Si element,indicating that the aerogel had been successfully covered.It can be seen from the SEM and AFM images that the Si O₂ aerogels was uniformly covered on the surface of the cotton fabric.Aerogels not only had hydrophobic properties but also provided micro-nano roughness to superhydrophobic surfaces.In addition,the presence of air in the pores of the aerogels also provided favorable conditions for the construction of superhydrophobic surfaces.Washability test showed that the prepared super-hydrophobic cotton fabric still had good hydrophobicity after 25 times of washing.Self-healing tests showed that the prepared cotton fabric samples had good self-healing properties after three times of plasma etching and baking.?3?Flower-like Cu S nanomaterials were prepared by hydrothermal/solvothermal method using cupric chloride as copper source and thiourea as sulfur source.Then,flower-like Cu S and polydimethylsiloxane?PDMS?were mixed to prepare PDMS/flower-like Cu S composite material via one-step method.Through the dipping-curing process,superhydrophobic and UV-blocking cotton fabric was obtained.The effects of various factors on the hydrophobic effect of cotton fabrics after finishing were discussed.The results showed that when the flower-like Cu S content was 4%,the amount of PDMS was 4%,the curing temperature was 160?and the curing time was 60min,the water contact angle of the prepared cotton fabric was 157.7°and the rolling angle was 7.2°,with excellent super-hydrophobic properties.XPS indicated that the finished cotton fabric had Si,C u,S and other elements on the surface,and the contents of C,O and other elements also increased obviously.It can be seen from the SEM and AFM images that the flower-like Cu S uniformly covered the surface of the cotton fabric under the"package"of PDMS,and the presence of air between the flower-like C u S nanosheets were benefical for constructing the superhydrophobic surface.The UV resistance test showed that the UPF value of cotton fabric after finishing was increased from 22 to 511,and the water contact angle still reached 152°after being exposed to high intensity UV lamp for 20h,with better superhydrophobic durability.Photocatalytic tests showed that the degradation rate of methylene blue of the treated cotton fabric was more than 90%,indicated that it had excellent photocatalytic performance.Therefore,the research and development of multi-functional textile had certain potential and application prospects.