Waterborne Polyurethanes: From Molecular Design and Structural Engineering to Advanced Functional Applications

Waterborne polyurethane (WPU) is an environmentally friendly supramolecular elastomer material, which uses water as the primary dispersion medium. Research on WPU advances high-performance, low volatile organic compounds (low-VOCs) materials that support sustainable manufacturing, environmental protection, industrial upgrading, and the development of next-generation functional polymer technologies. In this review, we summarize recent advances in WPU, mainly focusing on its synthesis strategies, structure-property relationships, and emerging applications. Particular attention is given to the unique structure-property relationships of WPU, highlighting how molecular design and phase structure regulation determine its comprehensive properties and functional performance. Representative applications of WPU across various industrial and emerging fields are summarized, emphasizing its versatility and potential for high-value applications. Finally, the current challenges and future opportunities of WPU are discussed, highlighting the need for rational molecular design and structural optimization to achieve high-performance, durable, and sustainable materials. This review provides comprehensive insights into the rational design, structure–property relationships, and future development of WPU materials, promoting their broader applications in advanced functional polymer fields.