超浸润性可逆切换的超双疏复合海绵材料的制备及油水分离应用

通过简单的溶胶-凝胶法制备了全氟癸基三甲氧基硅烷(PFDMS)-正癸酸(DA)-TiO₂溶液，经浸泡后得到PFDMS-DA-TiO₂超双疏海绵。PFDMS-DA-TiO₂超双疏海绵在质量分数为25wt%~28wt%的氨气诱导下，表面浸润性由超双疏切换为超亲水-空气中超疏油。利用FTIR和SEM对改性前后PFDMS-DA-TiO₂海绵表面进行表征，分析其化学组成和表面形貌，研究了DA的体积比对PFDMS-DA-TiO₂超双疏海绵表面浸润性可逆切换效果的影响，并对其耐盐性、耐磨性及油水分离性能进行了测试。结果表明:DA的最佳体积比为5.8%，其油水分离效率与通量分别可达99.6%、4775 L/(m2·h)。PFDMS-DA-TiO₂超双疏海绵经磨损实验及在质量分数为3.5wt%的NaCl溶液中浸泡12 h后，均保持优异的超双疏性能，表现出较高的耐磨性和耐盐性。经氨气诱导，其表面浸润性在超双疏与超亲水-空气中超疏油之间可逆切换20次后，两种润湿性能仍能各自保持稳定，可用于实际工业中高效可控地分离油水混合物。 

Preparation of superamphiphobic composite sponge material with super-wetting reversible switching and application in oil-water separation

The perfluorodecyltrimethoxysilane(PFDMS)-n-decanoic acid(DA)-TiO₂ solution was prepared by a simple sol-gel method, and immersed to obtain the PFDMS-DA-TiO₂ superamphiphobic sponge. Under the induction of ammonia gas with a mass fraction of 25 wt%–28 wt%, the surface wettability of the PFDMS-DA-TiO₂ sponge is switched from superamphiphobic to superhydrophilic and superoleophobic in air. The surface of the PFDMS-DATiO₂ sponge before and after modification was characterized by FTIR and SEM, and its chemical composition and surface morphology were analyzed. The effect of the volume ratio of DA on the reversible switching effect of the PFDMS-DA-TiO₂ superhydrophilic sponge surface infiltration was studied, and its salt tolerance, friction resistance and oil-water separation performance were tested. The results show that the optimal volume ratio of DA is 5.8%. At this time, the oil-water separation efficiency and flux can reach 99.6% and 4 775 L/(m²·h), respectively. After the PFDMS-DA-TiO₂ superhydrophilic sponge was subjected to an abrasion test and immersed in 3.5 wt% NaCl solution for 12 h, they all exhibit excellent superamphiphobic performance and sponges show high abrasion resistance and salt tolerance. After 20 times of reversibly switching of surface wettability between superamphiphobic and superhydrophobic-superhydrophilic in air induced by ammonia, the two wetting properties can still maintain their own stability, which can be used to effectively separate oil-water mixtures in practical industries.