莫来石晶须/堇青石表面层的制备及准超疏水性能

Preparation and Quasi-superhydrophobic Properties of the Surface of Mullite Whiskers/Cordierite

采用溶胶-凝胶法制备了硅铝混合凝胶粉体,再通过熔盐反应在堇青石陶瓷基体上生长莫来石晶须,制得莫来石晶须/堇青石表面层微结构.表征结果表明,莫来石晶须紧密生长在堇青石基体上,晶须直径为100~300 nm,长度可达几个微米.莫来石晶须表面含有大量Si-OH和Al-OH极性亲水基团,采用十二烷基三甲氧基硅烷与活性基团间的偶联反应将非极性基团引入莫来石晶须表面,获得了静态润湿角为146°的莫来石晶须/堇青石表面层.动态润湿研究表明,合成的莫来石晶须增大了堇青石陶瓷的表面粗糙度,使亲水的莫来石晶须/堇青石表面更加亲水,而硅烷偶联剂修饰的堇青石/莫来石晶须表面则成为准超疏水表面.

Silicon-aluminum hybrid gel powders were prepared by sol-gel technology, and the microstructure of mullite whiskers/cordierite was obtained through growth of mullite whiskers on the surface of cordierite ceramic substrate by molten salt reaction. X-Ray diffraction, scanning electron microscopy and energy dispersive X-ray spectroscopy were employed to characterized the structural morphology and phase compositions. The results show that the surface of cordierite ceramic was covered by dense mullite whiskers with nanometer-sized(100-300 nm) diameters and micrometer-sized lengths. The surface modification of mullite whiskers was performed by coupling reaction between n -dodecyltrimethoxysilan and numerous active groups(Si-OH, Al-OH) on the surface of mullite whiskers, and static wetting angle of this sample is 146°. Dynamic wetting studies show that mullite whiskers increase the surface roughness of cordierite ceramics, making the hydrophilic mullite whiskers/cordierite surface more hydrophilic and the surface of the mullite whiskers/cordierite modified by the silane coupling agent change into quasi-superhydrophobic surface.