Design And Preparation Of Micro-Nano Structures On The Superhydrophobic Surface Of Vulcanized Eucommia Ulmoides Gum

A fluorine-free super-hydrophobic surface with multi-scale roughness was constructed with the micron-scale crystalline structure of EUG as matrix and nano particles by using a series of method,such as template method,spin coating method and sol-gel method.The temperature response of surface properties can be achieved through the melting-crystallization of the crystalline structure.Through the special photoelectric effect of titanium dioxide(TiO₂),which can realize the surface properties of the light response,so as to prepare a super-hydrophobic surface with dual response of light and heat.Through the template method,the EUG-Al super-hydrophobic surface was prepared by stearic acid modification after the roughness of aluminum plate etched with hydrochloric acid solution was copied and transferred during vulcanization of EUG.By changing the concentration of the metal template etching solution and the etching time,different the morphology of the micro-nano structures on the surface of the vulcanized EUG were obtained.The influence of different micro-nano structures on the hydrophobic properties of the samples was also investigated.As a result,the WCA reached 169.2°and the surface of vulcanized EUG was successfully super-hydrophobicized.Through the spin coating method,the EUG-SiO₂super-hydrophobic surface was prepared with toluene dispersion of EUG,hydrophobic nano-SiO₂and dicumyl peroxide(DCP).The dispersion was spin-coated on the film surface with a certain thickness and vulcanized.The EUG-SiO₂super-hydrophobic surface with temperature response characteristics was prepared.The influence of the amount of hydrophobic nano-SiO₂on the wettability was studied,and the reason why the hydrophobicity of the surface changes with temperature was also discussed.The results showed that when the mass ratio of SiO₂to EUG reached 4:1,the surface exhibited the best micro-nano structure,and the measured WCA was 153.0°.The prepared super-hydrophobic surface can respond to ambient temperature stimulation,the contact angle changes in a cycle with the temperature change,and it still maintained good hydrophobicity after the temperature returns to room temperature.Through the sol-gel method,the vulcanized EUG was prepared with EUG,and the nano-TiO₂rough structure was formed in-situ on the inside and surface of EUG.The surface hydroxyl group of nano-TiO₂particles was modified,and the"micro-nano"composite was achieved with EUG micron-level crystalline structure finally.The effects of sol-gel reaction conditions,in-situ TiO₂surface modification on the surface properties and micro structure of EUG samples were investigated.The cyclic transformation of surface wettability induced by nano-TiO₂and EUG crystal structure was verified.As a result,the contact angle prepared by the best process can reach 159.1°.The photothermal double cycle response of surface properties can be realized by EUG the melting-crystallization of crystalline structure and the special photoelectric effect of TiO₂structure.