Self-healing transparent core–shell nanofiber coatings for anti-corrosive protection

Abstract

Dual emulsion electrospinning is introduced to form core–shell nanofiber coatings with the self-healing agent dimethyl siloxane (DMS) and dimethyl-methyl hydrogen-siloxane (cure) separately in the cores. The coating pores are also intercalated by polymerized (cured) poly(dimethyl siloxane) (PDMS) resin as an outer matrix. If such a coating is damaged, the self-healing agents (DMS resin and cure) are released separately from the nanofiber cores and are mixed. As a result, the mixture of DMS and cure is polymerized inside a scratch or micro-crack, and the surrounding PDMS matrix is self-healed. By direct experiments, we find that such protective coatings are highly transparent (with 90% transmittance). They also self-heal fast, even when the scratch goes through the entire mat thickness, and are capable of protecting the underlying steel substrate in corrosive environments [4 wt% NaCl solution or acetic acid (99.7%)].