High-enthalpy biphasic phase change organogels with shape memory function based on hydrophobic association and H-bonding interaction

Abstract

Low-temperature solid–liquid organic phase change materials (OPCMs) offer tremendous opportunities in thermal management techniques but suffer from leakage problems above the melting temperature. Here, inspired with the universal hydro/organogels using three-dimensional polymer networks capable of holding large amounts of liquid solvents, a kind of form-stable high-enthalpy biphasic phase change organogels (BPCOGs) were developed by the integration of hydrophobic association for synthesizing intrinsic phase change matrices and H-bonding interaction for binding OPCM liquids. The porous phase separated poly(acrylamide-octadecyl acrylate) (P(AM-co-OA)) matrices with uniformly dispersed thermal conductive carbon nanotubes were fabricated from the hydrophobically associating hydrogels (HAHs), in which POA segments provide the phase change energy storage microdomains and the PAM network is capable of binding a series of melted OPCMs by hydrogen bond engineering. The fabricated BPCOGs possess form-stability, high phase change enthalpy (high up to 215.5 J g−1) and high energy storage efficiency (>90%), and show excellent electrical/optical-thermal energy conversion as well as shape memory performances. This study provides a universal strategy to prepare flexible biphasic OPCMs suitable for a variety of solid–liquid OPCMs including fatty alcohols, fatty acids and polyethylene glycol, and demonstrates the great potentials of these BPCOGs in solar energy utilization and functional flexible devices.