PEG‐PS Block Copolymer‐Stabilized High Internal Phase Emulsion for the Preparation of Shape‐Stabilized Phase Change Material

Two amphiphilic block copolymers (BCPs), designated as the triblock copolymer PSt‐ b ‐PEG‐ b ‐PSt (TBCP) and the diblock copolymer PEG‐ b ‐PSt (DBCP), were synthesized via activators regenerated by electron transfer atom transfer radical polymerization(ARGET ATRP). The copolymers served as surfactants for the preparation of PolyHIPEs, which were subsequently vacuum‐impregnated with hexadecanol to yield a shape‐stable phase change material (SS‐PCM). The BCPs were identified as PS 47 ‐ b‐ PEG 45 ‐ b ‐PS 47 and PS 91 ‐ b ‐PEG 45 with number‐average molecular weights of 12 100 and 11 600 g mol −1 , respectively. The phase change properties, thermal stability, and thermal insulation performance of the SS‐PCM were evaluated. The prepared SS‐PCM exhibited high shape stability, high impregnation efficiency and excellent thermal insulation performance. Furthermore, the SS‐PCM derived from TBCP‐stabilized HIPE (TBCP‐SS‐PCM) showed better thermal stability, leakage resistance, and thermal insulation than that from DBCP‐stabilized HIPE (DBCP‐SS‐PCM). The 10% weight loss temperature of TBCP‐SS‐PCM was 10 °C higher than that of DBCP‐SS‐PCM. After 500 heating–cooling cycles, TBCP‐SS‐PCM exhibited a leakage rate 3% –7% lower than that of DBCP‐SS‐PCM. Compared with DBCP‐SS‐PCM, TBCP‐SS‐PCM exhibited lower maximum temperatures (47.5 vs. 50.8 °C), slower heating rates (1.02 vs. 1.21 °C min −1 ) and a lower cooling ratio (0.46 vs. 0.71 °C min −1 ). This difference arose from the stronger affinity between TBCP and hexadecanol compared with that between DBCP and hexadecanol.