Synthesis And Properties Of Fluorine-containing Finishing Agent With Reversible Hydrophobicity-hydrophilicity Transformation Through Optothermal Response

Researchers were interested in the materials with special wettability,which can be applied on waterproof,finishing,microbial medical,an so on,due to their unique properties.In those,reversible hydrophobicity-hydrophility on the substrate has become the research hotspots.It is easy to achieve the property of reversible hydrophobicity-hydrophility on metal surface.However,to our knowledge,the similar publication on the surface of fabrics is rare.In this dissertation,taking advantage of the isomerization of azobenzene group to control the conformation of terminal perfluoroalkyl group,reversible hydrophobicity-hydrophility on the surface of the fabric was obtained.Novel chemicals conaining perfluoroalkyl group and azobenzene group were synthesized by single electron transfer reaction,diazo coupling reaction and esterification followed by appling on different substrates.Afterwards,the optothermal response and the Hydrophobicity-Hydrophilicity Transformation of fabrics were studied.As a result,functional fabrics with the performance of reversible hydrophobicity-hydrophility were achieved successfully.The main discussions were as follows:?1?Silanes functionalized with perfluoroalkyl azobenzeneUsing bromoaniline and perfluoroalky iodide as raw materials,silanes functionalized by perfluoroalkyl azobenzene were synthesized by single electron transfer reaction,diazo coupling reaction and hydrosilylation.The structure of intermediates and target products was confirmed by FT-IR,¹H NMR and ¹⁹F NMR.Self-assembled monolayer?SAM?were successfully prepared on the surface of silicon wafer by chemical deposition with liquid phase.X-ray photoelectron spectroscopy?XPS?,energy dispersive X-ray diffraction?EDS?and atomic force microscopy?AFM?were used to get the structural information of SAMs.UV-visible absorption was applied to verify the photoisomerization of perfluoroalkyl azobenzene.The results showed that the perfluoroalkyl azobenzene monolayer isomerized well and provided good reversible wettability.The wettability of this smart surface can be controlled by combining photoisomerization of azobenzene groups with inherent migration of perfluoroalkyl groups.?2?Emulsion copolymerization and fabric finishing of perfluoroalkyl azobenzene polyacrylateTwo perfluoroalkyl azobenzene acrylates with different fluoroalkyl groups were synthesized by esterification.Then two types of fluoropolymethacrylates emulsion were prepared by Emulsion copolymerization and applied on fabric finishing.The results showed that the comformation of terminal perfluoroalkyl group on the side-chain transformed when the configuration of azobenzene units changed from trans-to cis-after the irradiation of UV light.This led to the increment of surface free energy by reducing fluorine content as well as the decrement of the contact angles.Berfoe and after optothermal treatment,the contact angles of treated cotton,silk and kevlar fabrics transformed between 131°/124°,125°/119°,132°/127°,respectively.Among them,the treated kevlar fabrics kept a good reversible recovery of contact angle even after 40 times of repeated optothermal treatment.?3?Modification of silk by controlled grafting polymerization via ATRPPreparaztion of fluoropolymer by traditional radical polymerization results the un-controllable structure.The main chain of these polymers will wind and thus cause the irregular arrangement of perfluoroalkyl and azobenzene group on substrates,the decrement of the efficiency of isomerization of perfluoroalkyl azobenzene.Controiling the degree of polymerization and obtain the grafting chain with narrow molecular weight distribution by using ATRP was carried out in our research.The regular arrangement of perfluoroalkyl and azobenzene group on silk fabric improves their controllable wettability.The results shows that the contact angles of grafting modified silk via ATRP transformed between122.2°and 77.8,and the smart surface with controllable and reversible hydrophobicity-hydrophility on silk was obtained by combining isomerization of azobenzene groups with inherent migration of perfluoroalkyl groups.