The Fabrication And Research Of Superhydrophobic Coatings On The Zinc Substrate

Superhydrophobic surfaces refer to those surfaces whose contact angle is greater than150o, and the sliding angle is less than10o, which is a typical representive of wettability.And superhydrophobicity has attracted a lot of attention for the extensive and potentialapplications on self-cleaning, and more reseachers feel more interested in themicro-nano composite structures and its potential applications.In this paper, we use the chemical replacement reaction combined with annealtreatment to build the Sn-Zn superhydrophobic surfaces with micro-nano compositestructures. The main results are as follows:(1) We fabricated Sn-Zn superhydrophobic surfaces with micro-nano structuresthrough the chemical replacement reaction combined with anneal treatment, which have acontact angle of159o and slide angle of2o. The equipments and experimental method issimple; No organic matter of low surface free energy is required to get to thesuperhydrophobicity. The characterization of the superhydrophobic surface and impactfactors (the etching time in hydrochloric acid, the reaction time with SnCl2, theconcentration of SnCl2solution, annealing temperature and annealing time) are analyzed indetailed, and illustrated that the micro-nano Sn-Zn composite structure is formed by thechemical displacement and anneal treatment.95.10%share of the air in the surface playsan important role in superhydrophobicity; Annealing plays a key role in the preparation ofthe superhydrophobic surface. Annealing, as a traditional industrial method, provides someexperimental basis for superhydrophobic materials in production applications.(2) Different reaction time leads to the superhydrophobic surfaces with two differentstates because of the high adhesion: the Cassie state as the lotus leaf surface andWenzel-Cassie transition state as petal surface. As to the superhydrophobic surface inCassie state with micro-nano Sn-Zn composite structure, the static contact angle is greaterthan150o, and the sliding angle is less than10o. The morphology of the superhydrophobicsurface in Wenzel-Cassie transition state is different from that in Cassie state, and the waterstatic contact angle is greater than150o, and the sliding angle is so large that the waterdropsuspend on the reversal surface; The superhydrophobic surface in Cassie state has a verygood self-cleaning capability as the lotus leaf and an environmental stability; Also the superhydrophobic surface has excellent corrosion resistance and anti-drag ability. Themethod is very simple without additional modification with material of low surface freeenergy and has a promising industrial application.