仿箬叶聚合物表面模板法制备与润湿性能研究

从师法自然出发,以静态接触角高达140°的箬叶下表面为仿生对象,使用2种模板法制备具有箬叶下表面微纳复合结构的聚合物仿生表面。采用扫描电镜观测聚合物仿生表面的微观形貌,借助接触角测量仪分析仿生表面的润湿性能。以箬叶下表面为模板,采用聚二甲基硅氧烷(PDMS)二次复形方法获得仿箬叶下表面,仅实现微乳突结构的部分复形,而大多数纳米片层结构缺失,其静态接触角与PDMS本征接触角相比只提高了7°左右。采用电铸与注射成型相结合的方法获得的仿箬叶聚丙烯(PP)表面,可基本实现微纳复合结构的复形,其静态接触角与PP本征接触角相比提高了50°以上,进一步采用低表面能的氟硅烷修饰注射成型仿箬叶PP表面,其静态接触角与PP本征接触角相比提高了70°左右,达到了133°±2°。但2种模板法成型的仿生聚合物表面均未能较好保留箬叶的动态润湿性能。实验结果表明,通过电铸-注射法构筑仿箬叶表面的微纳复合结构、在粗糙表面上修饰低表面能物质的双重途径可用于实现仿生疏水表面高效低成本的制备。

Replication by Template Methods and Wetting Properties of Indocalamus-leaf-like Polymer Surfaces

Learn from the nature, the undersurface of indocalamus leaf with water contact angle of 140° was taken as the mimetic object. Two template methods were chosen to fabricate polymer biomimetic surfaces which had the similar micro-nano hierarchical structure characteristics of the indocalamus leaf. The morphology and surface wettability of polymer biomimetic surfaces were investigated by scanning electron microscope and contact angle meter, respectively. The undersurface of indocalamus leaf was then used as a template. Only some replicated micro-papilla were found on the PDMS biomimetic surface fabricated by a double replica method, missing most nano-lamellar structures. The water contact angle of PDMS biomimetic surface was only increased by 7°, compared with that of PDMS flat surface. The PP biomimetic surfaces were fabricated by injection molding combined with electroforming process. Results showed that the most micro-nano hierarchical structures of indocalamus leaf were successfully transferred onto the PP surfaces. Compared with PP flat surface, the water contact angle of PP biomimetic surface was increased by 50°. The PP biomimetic surface was then modified by fluoroalkylsilane with low surface energy. Compared with PP flat surface, the water contact angle of modified PP biomimetic surface was increased by 70°, reaching 133°±2°. But the polymer biomimetic surfaces fabricated by these two template methods can not reserve the dynamic wettability of natural indocalamus leaf. Results showed that the injection molding combined with electroforming and modification by fluorochemicals could be used to fabricate biomimetic hydrophobic surfaces with high efficiency and low cost.