Review:Fabrication and Application of Zwitterion-based Functional Coatings

Zwitterion-based materials by virtue of their special physical and chemical characteristics have attracted researchers to utilize them for fabricating functional coatings. The simultaneous presence of positive and negative charges renders the zwitterion-based materials with electrostatically induced hydration properties, which enables a high resistance towards oily pollutants, nonspecific protein adsorption, bacterial adhesion and biofilm formation. This review starts from the working mechanism of zwitterions and covers the fabrication strategies of zwitterion-based functional coatings, namely the zwitterion-bearing binder route, the zwitterion-bearing additive route and the post-generation of coatings containing zwitterionic precursors. The applications of zwitterion-based functional coatings are discussed, including medical implants, marine antifouling and oil-resistant coatings, with focus on the relevant mechanisms of the zwitterion-containing coatings for a specific performance. Finally, some comments and perspectives on the current situation and future development of zwitterion-based functional coatings are given.

The progress on antifouling organic coating: From biocide to biomimetic surface

The advancement in material science and engineering technology has led to the development of antifouling(AF) coatings which are cheaper, durable, less toxic, and safe to the environment. The use of AF coatings containing tributyltin compounds was prohibited at the beginning of 2003, this necessitated the development of environmentally friendly coatings. The fouling release coating(FRC) lacks biocides and has low surface energy, low elastic modulus with smooth surface properties, hence a better release effect to fouling organisms. Several functional coatings have been recently developed based on fouling release(FR) technology to combat the effects of biofouling. Here, we provide a brief overview of innovative technologies and recent developments based on FRCs, including silicone, modified fluorinated polymer,cross-linked coatings, amphiphilic copolymer coating, hydrogel coatings, and biomimetic coatings. We also highlight the key issues and shortcomings of innovative technologies based on FRCs. This may give new insights into the future development of marine AF coatings.

Electrochemical Characteristics in Seawater for Cold Thermal Spray-Coated Al-Mg Alloy Layer

For corrosion protection of carbon steel in a marine environment,cold arc thermal spray coating was applied to the surface with Al and Al-Mg alloy wires.The surface hardness of Al and Al-Mg thermal spray coatings increased with Mg content.And the various electrochemical experiments were carried out to evaluate corrosion damage characteristics of the thermal spray coating layers.The Al and Al-Mg thermal spray coating layers presented negative potentials compared to carbon steel in corrosion potential measurements.And an anodic polarization experiment revealed a tendency of activation polarization with no passivation.Furthermore,the corrosion damage of the thermal spray coating layer in galvanostatic experiment was observed mainly at the defect area,and the Al-3Mg thermal spray coating layer presented less surface damages than others.In addition,the Al-3Mg thermal spray coating layer showed the lowest corrosion rate while having a sufficient driving voltage for cathodic corrosion protection.Therefore,it is an optimal thermal spray material for sacrificial anode.