Coordinate mechanical property and self‐healing performance by hydrogen bonding promoting microphase separation structures in waterborne polyurethanes

Abstract

AbstractSelf‐repairing materials aim to replicate nature's repair mechanisms, but their current properties are inadequate for commercialization due to the trade‐off between repair and mechanical properties. An environmentally responsive low‐temperature self‐healing aqueous polyurethane with different sequence structures was developed in which the WPU‐MD/APDS system exhibited excellent performance. Statically, the incorporation of MD (1,8‐diamino‐P‐menthane) enhances hydrogen bonding within the system and facilitates reversible weak dynamic bonding; microphase separation enables aggregation of disulfide bonds in the hard‐phase domain, thereby improving disulfide bond exchange rates. Dynamically, the inclusion of MD introduces a rigid ring structure and promotes microphase separation with increased hydrogen bonding, leading to enhanced mechanical properties of the materials. The material exhibited tensile strength of 27.37 MPa, elongation at break of 1353%, excellent elastic recovery ability, and high tensile toughness of 136 MJ m−3; a sample with thickness of 0.2 mm lifted weight greater than its own weight into 40,000 times without damage recovery at 40°C. Rheological analysis confirmed its self‐healing property at room temperature.