Superhydrophobic Effect Of Polyphenol Compounds/nano TiO₂ On Silk Fabrics Functional Organization Research

Silk is a protein fiber with excellent skin friendliness with the human body,but it is easy to stain during wearing because of its high hydrophilic and porous structure.The static contact angle（CA）of superhydrophobic surface with water is more than 150°,and the rolling contact angle（SA）is less than 10°,which leads to have anti-soiling and self-cleaning properties.Introducing superhydrophobicity into silk fabric with other functionalities simultaneously can improve their added value.However,most superhydrophobic surface face many problems in the preparation process,such as using toxic fluorinated reagents,complicated processes,high cost,and unsuitable for mass production.In addition,during actual use,superhydrophobic materials are susceptible to external environmental influences,such as mechanical abrasion and high temperature that deteriorate their hydrophobic stability and permanence,limiting their wide application.This thesis uses environmentally friendly polyphenolic compounds and inorganic nanomaterials to synergistically modify silk fabric and construct superhydrophobic silk fabric with self-healing and anti-UV properties.The main research contents and results are as follows:PDA/DTMS-nano TiO₂modified silk fabric was prepared by firstly deposited by dopamine rapid polymerization in Cu SO₄/H₂O₂system,and synergized with dodecyltrimethoxysilane（DTMS）modified nano TiO₂.Its CA was 156°,and SA was 5°.It had superhydrophobic property.SEM test results showed that polydopamine（PDA）and TiO₂of the modified fabric surface constructed micro and nano-level particles with uniform distribution,firmly wrapped in the silk surface;FTIR,XPS,and EDS showed that the fast polymerized PDA was deposited on the surface of the silk fabric,DTMS combined with nano TiO₂by Si-O-Ti bond and which reduced the surface energy of the fabric.After10 plasma etching-repair cycles and 1200 mechanical abrasion-repair cycles,all recovered superhydrophobicity by heating;Its ultraviolet protection factor（UPF）was75.81;Compared with the original silk fabric in terms of taking properties,the modified silk fabric increased strength and wrinkle resistance,and slightly reduced breathability;it had good anti-fouling self-cleaning property,chemical stability,and washing resistance.Tannic acid（TA）,widely available and inexpensive,was selected to reduce the cost further.Based on the principle of phenolic-metal networks（MPNs）,tannic acid was reacted with different metal ions to modify the silk fabric.The TA/Fe²⁺system with the best chelation rate and the hydrophobic effect was selected by the tests of absorbance of different metal salt/tannic acid solutions,K/S value of modified fabrics,and water contact angle,etc.The TA/DTMS-nano TiO₂finishing was combined to prepare TA/DTMS-nano TiO₂modified silk fabric,and its CA of 157°,SA of 5°with superhydrophobicity.The results of various tests and characterization showed that TA and Fe²⁺formed MPNs structure and deposited on the surface of silk fabric to build a rough structure with more uniform distribution.Then DTMS-nano TiO₂was applied to the fabric’s surface,and the nano TiO₂further improved the surface roughness.DTMS reduced the surface energy of the fabric,which made it superhydrophobic self-healing performance.The UPF of the modified fabric was 67.98,which had good anti-fouling self-cleaning,taking performance,and washing resistance;the modified fabric also had antistatic and photocatalytic properties,expanding the practical application value of silk fabric.