Ultra-stable phase change coatings constructed from dynamic boron ester crosslinked polymers and lipophilic MWCNTs

Abstract

Assuring the mechanical integrity of polymer-based phase change materials (PCMs) at temperature beyond the melt point of the polymer matrix has always been a challenge. Herein, a simple boron ester-based chemical cross-linking strategy is reported for the development of ultra-stable flexible polymer-based phase change materials. Three-dimensional boron ester crosslinked networks were constructed in paraffin wax (PW), olefin block copolymer (OBC) and styrene-ethylene-butene-styrene (SEBS) systems. Subsequently, we successfully esterified multi-walled carbon nanotubes by a special esterification technique to achieve good dispersion in oily PW. The L-MWCNT-doped crosslinked PCMs coatings can be in applied to any substrates including nonwoven fabrics, steel, and wood. The three-dimensional polymer network structure constructed by boron ester cross-linking ensures the tensile properties of PCM at high PW loading rates, with elongation at break and enthalpy as high as 1050 % and 177.8 J/g, and creates a robust polymer support skeleton, which guarantees the mechanistic integration of the FPCM, even at ultra-high temperature higher than the molten point of the polymer. Further by coating the fabric, a strong photothermal and thermal storage capacity was demonstrated in repeated cycle validation. This work provides a promising strategy for the future fabrication of high-performance, high enthalpy stretchable wearable thermally managed polymer phase change composites.