Nanoencapsulation of Organic Phase Change Material in Water via Coacervation Using Amphoteric Copolymer

Nanoencapsulation of phase change materials are receiving increasing attention because of enhanced thermal conductivity and thermal capacity as well as ease of incorporation into the matrix for a wide range of applications. In this work, we have developed a simple and efficient approach to fabricate nanoencapsulated organic phase change (NEPCM) particles in water via coacervation using an amphoteric and temperature-sensitive polymer. The chitosan-co-poly(methacrylic acid) (CTS-co-PMAA) copolymer plays dual functions as an emulsion stabilizer and a shell material. The fabrication steps involve emulsion formation, followed by coacervation to form particle shell through adjusting solution pH, and finally rigidization of the shell via glutaraldehyde cross-linking. This method achieves high encapsulation efficiency (up to 84%) with a PCM content of 66%, high thermal capacity (LH_s 165 J g^-1 and LH_m 169 J g^-1), and high thermal cycling stability over 100 phase change cycles.