Self-healing waterborne polyurethane coatings combine UV curing with antibacterial ZnO

Researchers report a waterborne polyurethane acrylate (WPUA) coating that unites three properties rarely achieved in a single formulation: intrinsic self-healing, UV-driven crosslinking, and antibacterial performance. Writing in the Journal of Materials Science, Hamed Javadi, Roya Sedghi, and Ismail Omrani describe how they built the dynamic healing function directly into the polymer backbone by incorporating 2-hydroxyethyl disulfide (HEDS) as a chain extender. Disulfide bonds can reversibly exchange with one another when heated, allowing the network to re-form across a scratch rather than simply resisting damage passively.

The coating backbone was assembled from an unsaturated polyester polyol (UNPES), isophorone diisocyanate (IPDI), and 2-hydroxyethyl methacrylate (HEMA), with PEG 400-diacrylate and the photoinitiator TPO enabling UV-induced crosslinking. Three thermally triggered self-healing formulations containing different HEDS concentrations reached gel contents of up to 90 percent. When scratched and held at 90 degrees Celsius, the coatings closed scratches extensively within 30 minutes, an outcome the team assessed qualitatively by optical microscopy.

The reversible sulfur–sulfur exchange reactions underlying this repair are what allow the crosslinked network to rearrange and flow back together at moderate temperature. To add antimicrobial function, the optimized formulation was modified with ZnO nanoparticles surface-functionalized with 3-(methacryloyloxy)propyltrimethoxysilane (MAPTMS) at three loading levels. The reactive vinyl groups on the modified particles covalently participated in the crosslinked network, which enhanced crosslink density, thermal stability, and surface hardness.

Because the particles are chemically incorporated into the network rather than merely blended in, they reinforce the coating structure itself. The nanocomposite coatings showed potent antibacterial activity against both Staphylococcus aureus and Escherichia coli, alongside exceptional abrasion resistance and strong adhesion to steel substrates exceeding 1.2 megapascals. Together with the healing and crosslinking results, these measurements point to a coating designed for applications where durability, self-repair, and microbial resistance are required at the same time.

The authors position the waterborne system as an eco-friendly platform that converges damage-responsive healing, UV-driven crosslinking, and sustained antimicrobial protection, making it a candidate for next-generation multifunctional protective coatings.

Subject of Research: Self-healing antibacterial UV-cured waterborne polyurethane acrylate coatings with disulfide dynamics and ZnO nanostructures

Article Title: Multifunctional UV-cured waterborne polyurethane acrylate coatings with dynamic disulfide healing and antibacterial ZnO nanostructures

Article References: Javadi, H., Sedghi, R., & Omrani, I. (2026). Multifunctional UV-cured waterborne polyurethane acrylate coatings with dynamic disulfide healing and antibacterial ZnO nanostructures. Journal of Materials Science. https://doi.org/10.1007/s10853-026-13986-0

Image Credits: AI Generated

DOI: 10.1007/s10853-026-13986-0

Keywords: waterborne polyurethane acrylate, self-healing coatings, disulfide exchange, UV curing, ZnO nanoparticles, antibacterial activity, MAPTMS silane, crosslink density, scratch repair, protective coatings, Multifunctional, UV-cured