Polymer crystallization under dual confinement of High internal phase emulsion templated crosslinked polymer

Abstract PolyHIPEs are multifaceted soft materials used in a number of promising applications. Herein, the phase change characteristic of macroporous crosslinked poly(ɛ-caprolactone) (cPCL) monoliths synthesized via high internal phase emulsion – ring opening polymerization (HIPE-ROP) was studied by crystallization under dual confinement. The first level of confinement was introduced by large dispersed phase volume (≥74%) which was augmented by crosslinking of polymer chains providing additional restrictions for crystallization on second level. Crystallization behavior was studied using DSC, FTIR, XRD and results were supportive of confined crystallization with clear observation of chain supercooling effect. The extent of supercooling was found to be directly related to the degree of crosslinking and porosity. DSC results reflected clear melting (31 to 38 °C) and crystallization (-31 to 8 °C) peaks while the structural integrity and porous morphology was retained after annealing at 150 °C, as observed in SEM. The liquid uptake values of cPCL monoliths reached as high as 45 g/g and recyclability up to 25th cycles of liquid sorption-desorption. The developed cPCL monoliths demonstrated regulated crystallization under dual confinement and may further be explored for their role and application as phase change material.