Double crosslinked networks waterborne polyurethane with self-healing, recyclable and antibacterial functions based on dynamic bonds and used for temperature/light sensor

Waterborne polyurethanes with excellent mechanical properties, self-healing under mild controlled conditions and multiple functions are a potential alternative for preparing sensor materials with a wide application prospect. Herein, we introduced dynamic ditelluride bonds and trimethylolpropane into waterborne polyurethane main chains to achieve dynamic polymer chains while maintaining the stability of crosslink networks; subsequently, zinc ions were added to form ionic bonds with carboxyl groups between molecular chains to prepare self-healing waterborne polyurethanes (DTe-WPU-Zn-x) with double crosslinked networks containing double dynamic bonds. The prepared waterborne polyurethane film exhibited excellent mechanical properties (36.08 MPa), satisfactory elongation (665.83 %), and rapid self-healing efficiency (self-healing efficiency with 84.42 % after 90 min of visible-light irradiation). Benefiting from the excellent self-healing efficiency of DTe-WPU-Zn-3, the film fragments can be recycled under ethanol and pressure with lighting for 2 h, and its tensile stress can recover more than 80 % of its original properties after three recycling processes, which is rarely reported for double crosslinked polymers. Furthermore, owing to the combination of telluric radicals and metal ions, the film also has excellent antibacterial properties, with 99.6 % and 96.2 % against E. coli and S. aureus, respectively. Importantly, depending on the stable double crosslinked networks, the prepared sensor has long-term stability and can sensitively monitor changes in human body temperature, and the sensor also has a sensitive light response due to the photodynamic response of ditelluride bonds on polymer chains. In addition, the sensor still has better strain, temperature, and light response after recycling treatment. This research provides a facile method to fabricate environmentally friendly water-dispersible polymers with excellent properties and multiple functions, which have potential applications in the field of smart devices and human-computer interaction.