Fabricating Polymer Superhydrophobic Surface By Thermal Microreplica Molding

Superhydrophobic materials have become a field with great scientific interests in recent years because of their potential applications at self-cleaning, anti-icing, fluid drag reduction, and so on. Generally, the microroughness of the surfaces and low-surface-energy modification are two key factors to achieve superhydrophobic surfaces. Now sol-gel method, solution method, electrospinning method, chemical vapor deposition method and template method are commonly used in fabricating the superhydrophobic surfaces.Nevertheless, some methods are complicated, time-consuming and expensive, which limit their practical applications and industrial manufacture. In contrast, the template method, which might combine with melt flow casting technique, becomes the most promising process in fabricating polymer superhydrophobic films in large scale.In this research, a new kind of AAO film with superhydrophobic property was prepared by the process of etching and fluorination based on the customized anodic aluminium oxide. At the same time, a PDMS film with regular microstructure was produced by cast replica molding with AAO film as template. In order to optimize the nanostructure and surperhydrophobicity of PDMS film, the conditions of casting and curing time was changed systematicaly. The results showed that the surface of the obtained PDMS film didn’t include nano-column structure. This maybe caused by the poor liquidity of prepolymer and high capillary effect and air resistance.Subsequently, a facile and valid method, thermal-pressing followed with stretching assistant peeling off, was developed to fabricate the superhydrophobic surfaces with mirco/nano-meter grass structure using the cheap AAO film as template. Then the enfluence of vacuum or not, pressing temperature, pressing time and peeling temperature on the mircostructure and wettability of the resulted surfaces were discussed systematacially. It was confirmed by SEM pictures that the surfaces of achieved PP and LDPE obtained nanograss structure. However, lots of threadlike nanolines emerged on the surface of gained HDPE by employing another template. This nanowine-structure might be formed by the excessive strech of PE permeated deeply within the nanoholes of AAO film when peeling off the template. Two kinds of the above structure both showed good superhydrophobicities. It was calculated that the actual contact area between the water drop and sample surface only was about10%of the total contact area.