Preparation And Properties Of Self Cleaning Fabric Based On Titanium Dioxide

In recent years,self-cleaning fabric has attracted more and more attention.It can not only alleviate the environmental and energy problems caused by washing,but also protect human body from environmental pollutants.The self-cleaning function is mainly realized by superhydrophobic and photocatalytic methods,but both methods have limitations.Most superhydrophobic surfaces contain fluorine which is harmful to the environment,and the hydrophobicity is easily damaged by oil;Although the photocatalytic surface can degrade organic compounds,it takes a long time to achieve self-cleaning.At present,most of the self-cleaning fabrics adopt a single superhydrophobic or photocatalytic form,which has some problems such as limited self-cleaning ability and complex preparation process.In order to improve the self-cleaning ability of fabric,polydimethylsiloxane(PDMS),a cheap,non fluorinated and environmentally friendly material with low surface energy,and titanium dioxide(Ti O₂)were selected to construct the superhydrophobic photocatalytic surface of fabric.Firstly,Ti O₂was modified to improve its photocatalytic activity and hydrophobicity.Then,PDMS and Ti O₂ were modified on the surface of the fabric by immersion method.At the same time,the preparation process and performance of self-cleaning fabric were explored.The main research contents and results are as follows:1.Nano silver was deposited on the surface of nano-Ti O₂ by in-situ reduction method with silver nitrate(Ag NO₃)as silver source and sodium borohydride(Na BH₄)as reducing agent,and then hydrophobically modified by hexadecyl trimethoxysilane(HDTMS).After UV-Vis diffuse reflectance spectroscopy(DRS),X-ray diffraction(XRD),infrared spectroscopy(FT-IR),transmission electron microscopy(TEM),contact angle and photocatalysis tests,it was found that Ag-Ti O₂ nanoparticles were distributed on the surface of Ti O₂;When the mass ratio of Ag NO₃ to Ti O₂ was 15%,the photocatalytic activity of Ag-Ti O₂ was the highest,the band gap decreased from3.24 e V to 2.95 e V,the photocatalytic response range was extended to visible light,and the catalytic efficiency was 10%higher than that of the original Ti O₂.When 0.2g Ag-Ti O₂ was hydrophobically modified by 20?L HDTMS,the contact angle of the particles increased from 0?to 139.3?,and the band gap remained unchanged.The results show that the hydrophobic modified and silver deposited Ti O₂ not only has higher photocatalytic activity,but also has good hydrophobicity,which is conducive to the construction of self-cleaning fabric.2.Soak the cotton fabric in PDMS/Cyclohexane Solution with Ti O₂,stir for 2 hours and then dry it to prepare self-cleaning fabric.FT-IR,SEM,X-ray energy spectrum(EDS),Atomic Force Microscopy(AFM),Thermogravimetric Analysis(TGA)and contact angle tests showed that the hydrophobicity of the self-cleaning fabric was the best when the volume fraction of PDMS was 1%,the mass ratio of hydrophobic Ag-Ti O₂ to PDMS was 30%,and the drying time was 80 min at 135?.The static contact angle and rolling angle of the self-cleaning fabric were 164.3?and 4.9?respectively;The surface of the fiber is coated with PDMS and hydrophobic Ag-Ti O₂,and there are dense micro nano rough structures with a roughness of 76.7nm.In addition,the self-cleaning fabric has excellent adhesion resistance,can avoid being polluted by common liquids,and can easily take away the surface solid pollutants through water drops,showing good self-cleaning performance.3.In the photocatalytic performance test,it is found that the self-cleaning fabric prepared by hydrophobic Ag-Ti O₂ particles has stronger photocatalytic performance than the self-cleaning fabric prepared by Ti O₂ particles.Hydrophobic Ag-Ti O₂ fabric can degrade methylene blue solution by49%after irradiation with high pressure mercury lamp for 4 h;The mixture of methylene blue and oil could be photodegradated within 30 min,and the surface remained good hydrophobicity after degradation.In the washing resistance and wear resistance test,it is found that the hydrophobic Ag-Ti O₂ self-cleaning fabric has strong washing resistance,and it still maintains high hydrophobicity after 10 hours of washing,but the hydrophobicity decreases significantly after 10 cycles of friction test.In addition,the air permeability of the self-cleaning fabric decreased by 33.4%;It is worth noting that the fabric achieves 93.6%separation efficiency when separating the mixture of dichloromethane and water,which makes it also have application prospects in the field of oil-water separation.