A facile strategy to resolve the contradiction between dispersion stability and coating anti-smudge performance of bio-based waterborne polyurethane under ambient condition

Abstract

It has been challenging to create a waterborne non-fluorinated anti-smudge coating product that is curable under ambient conditions (at room temperature and humidity) and performs superior repellence to both amphiphilic and lipophilic contaminants. Herein this work, this issue was addressed by introducing an aziridine (AZ) cross-linker into bio-based waterborne polyurethane grafted with 2 wt% poly(dimethylsiloxane) (WPU-g-PDMS) as an eco-friendly dewetting agent. The modified WPU-g-PDMS/AZ system achieves complete curing at room temperature, which enables the coating to have excellent anti-smudge and anti-corrosion properties. The results indicate the tri-functional AZ component could effectively cross-link with carboxyl groups present in WPU-g-PDMS under ambient conditions, preventing pollutants from adhering to the hydrophilic groups on the surface of the coating and significantly enhancing its anti-smudge performance. A wide range of contaminant liquids could slide off the coated surface without leaving any residues, and dust particles can be easily removed with a simple water wash, demonstrating its self-cleaning capability. Moreover, the anti-smudge characteristics of the coating could autonomously regenerate in instances of chemical corrosion or physical wear, highlighting its self-healing attributes. This study showcases the potential of utilizing bio-based materials and non-fluorinated dewetting agents to develop sustainable utility in both architectural and industrial applications.