Rapid UV-Curable Form-Stable Polyethylene-Glycol-Based Phase Change Material

Thermal regulation and waste heat energy harvesting have been a concern in different industries, including the electronics sector that sees an increasing usage with technological advancement and automation. A form-stable phase change material (FSPCM) is an excellent solution to the problem, where device temperatures can be regulated without any PCM leakage. However, most FSPCMs are generally too stiff and bulky for coating onto delicate component parts, and their integration does not fit easily in a segment of a manufacturing line. Therefore, a UV-curable form-table polyethylene-glycol (PEG)-based PCM was investigated with trimethylolpropane ethoxylate triacrylate (TMPEOTA) as the UV matrix to present a fast-curing and coatable PCM for irregular surfaces. PEG composites of four different molecular weights, i.e., PEG 400, PEG 750, PEG 1050, and PEG 2050, were successfully fabricated with 50-80% PEG loading in TMPEOTA. UV curing was achieved instantaneously, and Fourier transform infrared (FTIR) spectrometry confirmed the success with the disappearance of the distinct C = C peak at 1620 cm(-1). All samples were found to be form-stable even at temperatures above their melting point, with matrix features present and no liquid observed by optical microscopy, suggesting a solid-solid phase transition. Differential scanning calorimetry (DSC) measured the phase change temperature to be tunable between 2 and 48 degrees C depending on the molecular weight of the PEG employed, and the enthalpy change of melting achieved a maximum of 117 J g(-1). Thermogravimetric analysis (TGA) also validated their thermal stability up to 150 degrees C. These UV-curable FSPCMs would be useful in providing a thermal regulatory coating or complex 3D-printed shapes.