Preparation And Performance Of OTS/HD-KH@SiO₂ Durable Multifunctional Superhydrophobic Cotton Fabric

SiO₂ is one of the most widely used materials for the preparation of superhydrophobic coatings and applications because of its high stability,high strength,environmental friendliness and ease of preparation.However,conventional SiO₂ has problems such as poor adhesion to fabrics,a single function for textiles and easy loss of hydrophobic properties during application.In order to solve these problems and optimise the hydrophobic capability of SiO₂,HD-KH570@SiO₂ composites with a high degree of cross-linking and hydrophobic properties were prepared by a sol-gel grafting strategy and loaded onto cotton fabrics.The multifunctional superhydrophobic cotton fabric was then successfully prepared with the synergistic effect of the low surface energy substance octadecyltrichlorosilane（OTS）,providing a practical basis for improving the durability of superhydrophobic surfaces and expanding the application range of textiles.The following are the contents:（1）Exploring the optimal preparation conditions for HD-KH570@SiO₂ composites:The preparation conditions of HD-KH570@SiO₂ were optimised using the sol-gel particle size and the hydrophobicity of the finished cotton fabric as evaluation indicators.The results showed that the optimum preparation conditions were:0.3 g of SiO₂,7 wt%of silane coupling agent KH-570,3 wt%of HDTMS,1:1（v/v）of ethanol:water,4 h reaction time and 70°C.（2）Analysis and characterization of the structure and properties of HD-KH570@SiO₂composites:The crystalline structure,chemical groups and elemental composition of the HD-KH570@SiO₂ composites were characterized and analyzed.TEM analysis results showed that the conventional spherical nano-SiO₂ compounded with organosilanes（KH-570 and HDTMS）turned into a net-like structure of tight clusters;The FT-IR analysis results showed that KH-570and HDTMS were successfully grafted onto the nano-SiO₂ surface;the XPS and EDS analysis results showed that three elements of C,O and Si were present in the modified nano-SiO₂,which proved that KH-570,HDTMS and SiO₂ were successfully compounded.（3）Exploration of the optimal preparation process of OTS/HD-KH@SiO₂ cotton fabric:the effects of OTS/H₂O molar ratio,reaction time,dilution volume,baking temperature and time on the hydrophobic properties of the finishing cotton fabric were investigated.The results showed that when the OTS/water molar ratio was 1:2,the reaction time was 1 h,the dilution volume was7%,the baking temperature was 80°C and the baking time was 150 s,the OTS/HD-KH@SiO₂cotton fabric had the best superhydrophobic performance with a contact angle of 164.2°and a rolling angle of 5°.（4）Study and analysis of the properties and applications of OTS/HD-KH@SiO₂ cotton fabrics:The microscopic morphology,elemental composition and chemical groups of OTS/HD-KH@SiO₂ cotton fabrics were investigated.SEM analysis showed that a dense and highly oriented bilayer structure was formed on the fibre surface under the synergistic effect of modified SiO₂ and OTS.EDS analysis showed that FT-IR analysis shows that the modified SiO₂ is successfully loaded onto the cotton fabric and cured by OTS,and the superhydrophobic cotton fabric is successfully prepared.The results of the friction,washing,acid and alkali,high and low temperature and heat and humidity aging tests show that the OTS/HD-KH@SiO₂ cotton fabric maintains good hydrophobic properties after 3000 times of mechanical abrasion,36 h of acid and alkali salt solution impregnation,20 times of washing,12 h of high and low temperature standing and 12 h of water vapour treatment.KH@SiO₂ cotton fabric has the ability of self-cleaning,anti-fouling and oil-water separation,and the efficiency of oil-water separation under the action of gravity reaches more than 98%.