Preparation of novel phase-change microparticles encapsulated by one-dimensional materials to significantly enhance heat transfer and photothermal conversion

Phase-change materials (PCMs) are widely used for thermal management in electronic devices because of their impressive heat storage capacity and suitable operating temperature range. However, their temperature regulation efficiency is often limited by issues like low thermal conductivity and potential leakage. To address these, a novel method combining emulsion polymerization (without an emulsifier) and high-speed shearing was developed to create paraffin wax (PW) phase-change microparticles. These microparticles are coated with ammoniated multi-wall carbon nanotubes (NH 2 -MWCNT), forming a structure akin to a “silk layer” that mimics silkworm cocoons. The prepared PW@NH 2 -MWCNT-3 sample demonstrated no leakage in shape stability tests, with a thermal conductivity of 2.90 ± 0.02 W/(m·K). These composite microparticles showed good circulability and excellent phase-change stability across 1000 heating and cooling cycles, with a high photothermal conversion efficiency of 97.1 %, enhancing device warming in cold environments. Additionally, flexible composite films (PAMCF) made of polyvinyl alcohol (PVA) and the prepared microparticles were prepared through a simple tape casting process. These films showed remarkable flexibility and doubled the thermal conductivity compared to pure PVA films, highlighting their potential to improve PCM applications in electronic thermal management. • Microparticles like cocoons prepared by emulsion polymerization without emulsifier. • Composite microparticles improve thermal conductivity by 1108.3 % over PW. • The thermal conductivity of composite microparticle film is twice that of PVA film. • Composite microparticles exhibit photothermal conversion efficiencies of 97.1 %.