Flexible loofah sponge-based phase change composite for thermal protection and wearable thermal management

Abstract

To address the escalating demand for sophisticated thermal management in electronics, energy batteries, and wearable devices, extensive research has been dedicated to developing shape-stabilized and highly thermally conductive phase change composites (PCCs). However, their inherent rigidity and limited flexibility pose significant challenges for practical applications. In response, we have engineered a novel and flexible PCC by integrating loofah sponge (LS) and styrene-isoprene-styrene block copolymer (SIS) as co-supporting framework with paraffin wax (PW) as heat storage medium, further enhanced with carbon nanotubes (CNTs). The process began with the vacuum adsorption of PW into an ammonia-softened LS, which forming a fibrous network. This was followed by the introduction of a mixed melt of SIS and PW, physically cross-linked and dispersed with CNTs, into the LS fibrous network. The composite was then cooled and shaped to produce the (final) PCC. The resultant PCC exhibited remarkable ductility with an elongation of approximately 780 % and a maximum tensile strength of ∼2 MPa. Furthermore, it maintained thermal reliability and dimensional stability over long-term usage, with a melting heat enthalpy as high as 146.4 J/g. This flexible PCC, which combines high latent thermal energy storage, temperature regulation, and thermally induced assembly properties, shows considerable promise for thermal protection and portable thermal management in electronic devices.