Super Hydrophobic Polymers On The Surface Of The Optical Adhesion Sex Research

At present, super-hydrophobic surfaces have attracted much attention in the study of solid surface wettability due to their various applications in waterproof, self-cleaning and so on. The research work of super-hydrophobic surfaces has experienced a three-stage development from the synthesis of pure super-hydrophobic surfaces to the construction of multifunctional super-hydrophobic surfaces, and now it focuses on the production of smart super-hydrophobic surfaces with special responsibility. For these smart super-hydrophobic surfaces with controllable wettability, it is more interesting to discuss their adhesive property, which decides the dynamic behavior of liquid on the surfaces. Stimulus-responsive adhesive property means the same super-hydrophobic surface could exhibit water repellent or water adhesive in different condition, which could be used in the area of no-loss micro-droplet transfer. In this work, we developed a photo-responsive smart surface, the wettability and adhesive property of which can be controlled by light.In the previous work, we reported the photo-responsive behavior of azobenzene-containing crosslinked liquid crystalline polymer (CLCP). Meanwhile, the properties of this material, such as responsive condition and mechanical performance, could be manipulated by adjusting a few factors. Herein, a kind of azobenzene-containing monomer and its linear polymer were synthesized, structures and molecular weight of which were studied. Furthermore, a novel liquid crystal (LC) cross-linker which contains a long flexible spacer was synthesized. A new kind of LC cross-linker which does not contain azobenzene was also used. The LC properties of both cross-linkers and their mixtures were studied and it was found that the mixture showed wide temperature range of LC phase, which profit the preparation of CLCP films.To obtain a super-hydrophobic surface, roughness has to be involved. In the experiments, patterned surfaces with four different pattern sizes were adopted. These rough substrates were silicon wafers with squared-arrayed square posts which were prepared by photolithography. Futhermore, the micro-nano composite structures of the silicon substrates were obtained by chemical corrosion. We construct photo-responsive super-hydrophobic substrate by coating the silicon wafers with azobenzene polymer. The adhesive property of the polymer surface can be controlled by light.Using the pattened silicon wafer as template, a soft template made from polydimethylsiloxane (PDMS) was created by duplicating the surface of silicon substrate. An LC cell was prepared by conglutinating the PDMS soft template with a rubbing glass substrate. The patterned CLCP film was synthesized by photo-polymerization in the LC cell, and the resulting film surface has the same microstructures with silicon substrate. The adhesive property of the film surface can be also controlled by light.