飞秒激光加工不对称浸润特性金属网格的研究

The Asymmetric Wetting Property Research in Using Femtosecond Laser Processing Printer Powder Coated Mesh

近年来,由于越来越多的工业含油污水产生和频繁泄油事故的发生,因此开发用于油水分离新技术十分重要。传统的油水分离材料由于存在制备工艺复杂,商业可用性低以及无法适应恶劣环境,大多数方案都无法进行大规模生产,且无法对重密度和轻密度油同时生效。受到鱼鳞的启发,制备了一种具不对称浸润特性的金属网格。通过用飞秒激光处理不锈钢网的一面,并在另一面上喷涂打印机粉末,使得网格的两面对水和油表现出不同的亲疏性。激光处理的表面超亲水并且水下疏油,此侧对水的接触角降为接近0°,对油的接触角增加至131°;而喷涂粉末的表面亲油并且疏水,此侧水的接触角增加至138°,而油的接触角将为0°。因此当油水混合物接触到金属网格某一面时,表现出亲性的液体就会在重力作用下透过网格,而表现出疏性的一面则会被阻隔,从而实现了油水的分离效果,且该网格对重油和轻油的分离均有效果,二者的分离效率均超过95%。

Oil-polluted water has recently become a global challenging task due to expanding industrial oily wastewater production and frequent oil spill accidents. It is of great importance to create novel technologies to separate oil and water, while the traditional methods have limitations for large-scale fabrication, due to complicated processes,low commercial availability,and inability to adapt to harsh environment. Inspired by fish scale, we developed a novel functional material by coating printer powder(PP) on femtosecond laser treated stainless steel mesh. The stainless steel mesh was first cleaned in ethanol by ultrasonic wave at room temperature and dried in the air, and then scanned by fs laser to create hierarchical structures. Printer powder was mixed with waterborne polyurethane and acetone to obtain a homogeneous suspension. The suspension was then sprayed onto the stainless steel mesh substrate on the untreated side with compressed air gas using a spray gum. Finally, the printer powder coating was dried at ambient temperature to allow the acetone to evaporate completely. The laser treated side was superhydrophilic in air and superoleophobic underwater, the water contact angle decreased to nearly 0°and the oil contact angle increased to 131°on this side;while the printer powder coated side was superoleophilic in air and superhydrophobic in oil, the oil contact angle increased to 138°and the water contact angle decreased to 0°.This asymmetric wetting property allows only one liquid to permeate the mesh when the oil/water mixture meets it, and this mesh is workable for both heavy oil/water mixture and light oil/water mixture, the separation efficiency for two types of mixture is above 95%.