Study On Hydrophobic And Oleophobic Modification Of Fabrics And Directional Liquid Transport Properties Of Material

Directional liquid transport materials have wide application prospects due to their special liquid transport properties,such as functional textiles,microfluidic transport,oil-water separation and fog water collection.At present,most of the preparation of directional liquid transport materials are based on the directional transport of water.While in real life and industry,due to the wide use of low surface tension oil,the research on the transmission performance of materials to liquids with different surface tension is of great significance to the intelligent control of liquids and the development of advanced oil-water separation technology.Therefore,starting from the preparation of water and oil repellent surface and the design of wettability,the hydrophobic polymer polyvinylidene fluoride and low surface energy fluorosilane were selected,and the hydrophobic and oleophobic surface was prepared on amphiphilic fabric and fiber membrane substrate by electrostatic spraying and electrospinning,and the directional liquid transport performance of the material was studied.In addition,the effects of symmetrically oriented liquid transport properties on liquid transport and wicking effects of different structural materials were also studied.(1)PVDF/FAS spraying solutions with different concentrations were prepared without adding inorganic nanoparticles.The surface of cotton fabric was modified with water and oil repellent characteristic by single-sided electrostatic spraying.The wettability gradient of amphiphobic-to-amphiphilic was constructed along the thickness direction of the fabric.By controlling the thickness of the spraying layer,the modified fabric has directional transmission performance to water and oil with different surface tension.The directional water and oil transport properties of fabrics prepared with different concentrations of spraying solution were compared.The results showed that in the concentration range we choosed,the increase of the concentration of spraying solution will reduce the efficiency of directional water/oil transmission.(2)Based on the design of Janus wettability,Janus double-layer fiber membrane was prepared by combining amphiphobic PVDF/FAS and amphiphilic PAN fiber membrane.By controlling the parameters of electrospinning,the Janus fiber membrane has directional transmission to water and hexadecane.The effects of pore size structures of amphiphilic layer and amphiphobic layer on directional water/oil transport efficiency in Janus fiber membrane were studied.The results showed that the combination of larger pores in lyophobic layer and smaller pores in lyophilic layer could improve the directional water/oil transport efficiency of Janus fiber membrane.By controlling the parameters of electrospinning,the Janus fiber membrane has directional transmission to water and cetane.The effects of pore size structures of lyophilic layer and lyophobic layer on directional water/oil transport efficiency in Janus fiber membrane were studied.The results showed that the combination of larger pores in lyophobic layer and smaller pores in lyophilic layer could improve the directional water/oil transport efficiency of Janus fiber membrane.(3)In order to study the effects of unilateral and bilateral symmetrical liquid transport properties on the liquid transport behavior and wicking behavior of fiber membrane,lyophobic-lyophilic double-layer fiber membrane,lyophobic-lyophiliclyophobic and lyophilic-lyophobic-lyophilic three-layer fiber membrane were prepared.The results showed that the directional water transport and directional oil transport properties can promote the transfer of liquid from amphiphobic layer to amphiphilic layer,and will enhance the wicking effect of fiber membrane.In addition,the bilateral directional water transport and directional oil transport performance will have an additive effect on the wicking effect on lyophobic-lyophilic-lyophobic three-layer fiber membrane.