A 3D-dynamic networks strategy utilizing SiO2-nanoscale ionic materials in novel waterborne polyurethane ionic nanocomposites for fast self-healing and UV-blocking performance

Abstract

Waterborne polyurethane (WPU) is one of the most applicable products used in various industries to manufacture smart coatings with self-healing ability due to its being environmentally friendly. However, the self-healable WPU coatings suffer from long healing times, low transparency, and poor physicochemical properties. Herein, ionic nanocomposite coatings were prepared based on SiO2-nanoscale ionic materials (SiO2-NIMs) and novel WPU, with fast self-healing ability, high transparency, and UV-blocking performance. We demonstrate that SiO2-NIMs can significantly act as a unique healing agent in the WPU due to their fluid 3D-dynamic networks of hard core-corona (SiO2-SO3−) and soft segments (canopy). The optical micrographs show the WPU film containing 3 phr SiO2-NIMs completely repaired after 20 min at 50°C. The tensile test illustrates that elongation at break, tensile strength, and toughness values of the healed sample recovered 78.2%, 94.2%, and 69.3% of the original film, respectively. The differential scanning calorimetry, x-ray diffraction, and dynamic mechanical-thermal tests were applied to confirm core-corona-canopy segments' hardening and excellent damping behavior in the WPU matrix. The thermogravimetric and tensile analyses demonstrate that SiO2-NIMs can enhance the thermal stability and mechanical properties of WPU. This study introduces a novel strategy based on SiO2-NIMs for preparing self-healing polymers with outstanding physicochemical properties. Highlights: Synthesized novel WPU based on anionic Congo red. Introducing a novel strategy-based SiO2-NIMs for self-healing of coatings. Enhancement of self-healing and thermo-mechanical properties of the WPU. Introducing healable and UV-blocking abilities of ionic nanocomposite coating. © 2025 Society of Plastics Engineers.