Self‐Matting Waterborne Polyurethane Coatings With Ultra‐Low Gloss and Enhanced Corrosion Resistance via Molecular Design and ZnO Integration

ABSTRACT Self‐matting waterborne polyurethanes (WPUs) are increasingly demanded in the automotive, architectural, and furniture industries for their ability to reduce visual fatigue and deliver refined aesthetics. However, their limited corrosion resistance restricts applications in harsh environments. This study addresses this challenge through a dual strategy: (1) molecular optimization to achieve ultra‐low gloss via self‐wrinkling morphology and (2) incorporation of zinc oxide (ZnO) nanoparticles to enhance corrosion resistance. By systematically adjusting the polytetrahydrofuran (PTMG) to polyethylene glycol (PEG) mass ratio (mPTMG: mPEG = 164.4:10), dimethylolpropionic acid (DMPA) content (1.8%), and NCO/OH ratio (2.1), a self‐matting WPU coating with a 60° gloss of 1.0 GU and an 85° gloss of 7.3 was developed. FTIR, SEM, and 3D profilometry confirmed microphase‐separated structures and surface roughness were critical for light scattering and highly affected the gloss of the WPU films. The WPU films also displayed excellent mechanical properties. Furthermore, introducing ZnO nanoparticles (0–5 wt%) significantly improved corrosion resistance, as evidenced by electrochemical impedance spectroscopy and salt immersion tests. Optimized ZnO‐composited WPU exhibited a ninefold increase in impedance modulus compared to pristine WPU, demonstrating effective barrier properties against corrosive agents. By bridging the gap between low‐VOC matting performance and corrosion resistance, this work expands the applicability of WPUs in industries requiring sustainable and high‐performance coatings for harsh environments.