Shape-Stable Hydrated Salts/Polyacrylamide Phase-Change Organohydrogels for Smart Temperature Management

Flexible and environmentally friendly phase-change materials (PCMs) with appropriate phase transition temperatures display great potential in the regulation of environmental temperature. Here, we synthesized a series of room-temperature-use phase-change organohydrogels (PCOHs) comprising phase-change hydrated salts (disodium phosphate dodecahydrate, DPDH) and polyacrylamide (PAM) glycerol hydrogels through a facile photoinitiated one-step in situ polymerization procedure. Incorporating the environmentally friendly cost-effective DPDH hydrated salts PCMs into antidrying three-dimensional (3D) networks of the PAM organohydrogel can overcome the solid rigidity and melting leakage to achieve flexibility for wearable temperature management devices. The microstructures and physical interactions among the components of the PCOHs were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR), and X-ray diffraction (XRD), which demonstrate that the DPDH were uniformly loaded in the networks of the PAM. Phase-change storage and thermal properties of the PCOHs were characterized by differential scanning calorimetry (DSC) and thermal gravimetric analysis (TGA), and the PCOHs show high energy transition efficiency and shape stability during the long-term storage and thermal cycling. Dynamic rheology and compression tests demonstrate that PCOHs can withstand a certain stress and display flexibility performance even above the melting temperature of DPDH. We also described the smart temperature management capability and the potential application of the PCOHs. This investigation offers a facile method to construct a skin-friendly flexible phase-change glycerol hydrogel and provides an alternative to the traditional melt impregnation or microencapsulation method to prepare phase-change energy storage composites.