Preparation And Property Of Superhydrophobic Antifouling And Antibacterial Fabrics Coating Based On Functional Mesoporous Silica Spheres

Fabrics,which are indispensable materials in human life,can provide important safety protection for our body.However,due to the hygroscopicity and porous structure of common fabrics,pathogenic microorganisms such as bacteria or fungi are liable to adhere to and multiply on the surface,resulting in the decrease in air permeability and mechanical properties of fabrics.What’s worse,the pathogens may cause cross-infection,and lead to the spread of diseases and threaten humans’life.Therefore,functionalized fabrics coatings,which can effectively prevent the adhesion of pathogenic microorganisms and kill them,have always been research hotspots in academia and industry.However,the defects of current fabrics coating technologies,such as complex process operation,high cost or specific requirements for the type of fabric,seriously limit the application of antifouling and antibacterial fabrics.In this paper,with the goal of simply and conveniently endowing fabrics with long-lasting antifouling and antibacterial functions,antifouling and antibacterial fabrics were prepared by dip coating or spraying method,combining the surface superhydrophobic mechanism of natural nano-topology with antibacterial activities of quaternary ammonium salts or nano-silver.Polydimethylsiloxane（PDMS）was used as the adhesive to modify functional mesoporous silica spheres（MSNs）on the surface of the fabrics.Besides,the relationship between the structure and function of the fabrics-functional coating was also studied.The main works are as follows:（1）Using tetraethyl orthosilicate（TEOS）as precursor and fluorinated silane coupling agent（FAS）as functional group,fluorinated mesoporous silica spheres（F-MSNs）were prepared by sol-gel method.Using PDMS as binder,F-MSNs were firmly bonded to the surface of the fabrics by dip coating process to form the nano-rough coating.The surface of obtained fabrics had excellent antifouling performance,for the static water contact angles（CAs）are up to 158±2o,and maintained the original properties of fabrics such as air permeability and flexibility.In addition,Janus cotton fabrics with a hydrophilic side and a hydrophobic side at the back was also prepared by spraying process.The experimental results showed that the hydrophobic layer can effectively block water droplets to impart antifouling abilities to fabrics;the hydrophilic layer can absorb water droplets to realize the rapidity of moisture absorption.Note that the hydrophilic and hydrophobic layers work in a stable and non-interfering way.（2）Antibacterial functional mesoporous silica spheres（Q-MSNs）were prepared by introducing modifying quaternary ammonium salts（QAS）on mesoporous silica spheres,and then Q-MSNs and F-MSNs were combined to construct superhydrophobic antifouling and antibacterial bifunctional coating on the surface of the fabrics.The study reached the conclusion that when the mass ratio of F-MSNs to Q-MSNs is at 4:2,the functionalized fabrics had the best antibacterial effect and high antifouling performance.In addition,the functionalized fabrics could maintain good antifouling and antibacterial properties even after abrasion and washing,which meant that the designed bifunctional fabrics coating had excellent mechanical stabilities.The antifouling and antibacterial synergistic mechanism of the bifunctional fabrics above-mentioned was as follows:firstly,the superhydrophobic antifouling surface of fabrics reduced the adhesion of pathogenic microorganisms such as bacteria;secondly,few pathogenic microorganisms adhered could be efficiently killed by QAS;thirdly,the dead pathogenic microorganisms can barely adhere to the surface of fabrics and were easily detached from the surface,thereby ensuring that the QAS could continue to play antibacterial effect.（3）Based on the research above on contact-type antibacterial and antifouling fabrics,this paper further explored a release-type antibacterial and antifouling fabrics coating containing nano-silver with an aim of further improving the long-term antibacterial efficacy of fabrics coating.Silver nitrate was reduced in ethanol solution containing mesoporous silica spheres to prepare composite nanoparticles（Ag-MSNs）with good dispersibility,and then the F-MSNs and Ag-MSNs were bonded to the surface of fabrics by dip coating process to form antifouling and antibacterial functionalized fabrics.CAs of the functionalized fabrics could reach 151±2o,which meant that the functionalized fabrics were superhydrophobic.At the same time,due to the synergistic effect of antifouling and antibacterial,the antibacterial rate of the functionalized fabrics was still as high as 92.3%（E.coli）and 90.1%（S.aureus）after30 days.In addition,the study found that the content of PDMS was the key to determining the antibacterial effect:when the content of PDMS in the dispersion solution reached 0.02 g m L^-1,the antibacterial performance of prepared functionalized fabrics was significantly reduced,and the bacterial inhibition zone disappeared resulting from the hindering effect of a large amount of PDMS to the release of Ag⁺.Therefore,an appropriate amount of PDMS played a key role in maintaining the long-term release of Ag⁺and ensuring the long-term antibacterial properties of functionalized fabrics.（4）In order to avoid the biotoxicity of fluoride and improve the biosafety of superhydrophobic antifouling and antibacterial fabrics in wound protection applications,this paper further designed alkylated mesoporous silica spheres loaded with silver oxide（Ag₂O-MSNs@OTES）.Hydrophobicity test showed that the prepared Ag₂O-MSNs@OTES could prevent the infiltration of water droplets and had good hydrophobicity.Meanwhile,the antibacterial experiments showed that the prepared Ag₂O-MSNs@OTES had bactericidal rate of 99.99%against E.coli and S.aureus at 40μg m L^-1.The fluorine-free superhydrophobic antifouling and antibacterial fabrics,modified with Ag₂O-MSNs@OTES,were prepared by dip coating process.The wound healing experiments of rats show that the functionalized fabrics could well protect the wound from external bacterial infection and provide a long-term sterile environment for the wound to heal.In this paper,starting from the construction of functionalized mesoporous silicon spheres,contact-type and release-type antibacterial and antifouling fabrics coating were designed successfully,which could be stably introduced to the surface of various fabrics by simple dip coating or spraying process.The above coating process had the characteristics of convenience and universality,which not only had great application potential,but also provided new ideas for improving and expanding the applicability and functionality of fabrics.