No abstract

No abstract

No abstract

Phase change composites (PCCs) integrated with leakproof characteristics, high thermal conductivity, and excellent photoabsorption ability have been proven to be of great use in many fields. However, the real-life application of most of the reported PCCs remains challenging due to their strong fragility and inferior mechanical performance. Meanwhile, solid−solid phase change materials (SSPCMs) based on molecularly engineered structures exhibit intrinsic flexibility but lack thermal conductive and photoabsorption ability. So, it is significative and critical to combine the merits of SSPCMs and PCCs for the real-life application. Herein, we introduced PEG8K and graphene nanoplates (GNPs) into a dynamic cross-linked polymeric skeleton to yield dynamic SSPCM-based composites (DSSPCCs). The fabricated DSSPCCs underwent a leak-free phase change process with a high enthalpy value (93.74 J/g) and showed excellent stability and mechanical flexibility. Meanwhile, the DSSPCC with 3 wt % GNPs exhibited higher thermal conductivity (1.071 W•m −1 K −1 ) than other reported SSPCM-based composites and excellent photo-to-thermal conversion ability (temperature reached 120 °C within 65 s under near-infrared irradiation). Moreover, our DSSPCCs possessed outstanding recyclability and solid-state plasticity, originating from the dynamic feature of urethane bonds. The excellent comprehensive properties of the DSSPCCs guarantee they are suitable to be used as various thermal interface materials, thermal energy storage units, and energy saving building materials.

Combining photohealing and reprocessing in covalent adaptive networks (CANs) offers a convenient healing condition and extended life span. Herein, we propose a strategy to fabricate photohealable polyurethanes (PHPUs) by molecule design. Benefiting from their permanent covalent crosslinking structure, PHPUs present superior mechanical robustness and high healing ratio; specifically, their tensile strength attains 36 MPa and toughness attains 86 MJ/m 3 . Furthermore, PHPU-3 exhibits an excellent healing ratio of 99%/94% under heat/photostimulation. Additionally, the shape programming of the PHPUs can proceed under the remote control of infrared (IR) light. The combination of the above performance provides PHPUs with a practical application prospect.