This is a self-repairing water-based paint with "soft inside and rigid outside"!

Coatings are widely used in various fields such as automobiles, ships, decoration, construction and furniture

Recently, Lu Xun’s team from South China University of Technology used isophorone diisocyanate, polyester polyol, 2,2-bis(hydroxymethyl)propionic acid, and 2,6-diaminopyridine as raw materials to coat the Zn2+ solution on The surface of the water-based coating forms an "inner sparse and outer dense" concentration gradient Zn(II)-carboxyl and Zn(II)-diaminopyridine bimetallic coordination structure on the coating by means of ion penetration, and a gradient complex is prepared.

Figure 1 Schematic diagram of the structure of water-based poly(urethane-urea) "flexible inside and rigid outside"

Figure 2 (a) SEM image of the cross section of WPUU-5Zn-3 coating; (b) energy dispersive spectrum images of zinc in different areas (top, middle, bottom of the cross section); (c) element detection in the top area of ​​the cross section; (d) Element detection in the middle area of ​​the cross section; (e) Element detection in the bottom area of ​​the cross section; (f) Schematic diagram of the structure of the WPUU-5Zn-3 coating

Figure 3 (a) The mass loss rate of different WPUU-xZn-y coatings after scratch resistance test; (b) The photo after scratching WPUU-3 and WPUU-5Zn-3 with a copper brush; (c) Different WPUU- Bond strength of xZn-y coating

Figure 4 Optical microscope image of the self-healing ability of WPUU-5Zn-3 coating on scratches of different depths

Figure 5 (a) Three-dimensional morphology evolution of WPUU-5Zn-3 coating: (i) before repair, (ii) after repair; (b) in a humid and hot environment (60℃, 98% RH), WPUU-5Zn- 3 Corresponding scratch depth profile of the coating before and after healing