Development of photoluminescence phase-change microcapsules for comfort thermal regulation and fluorescent recognition applications in advanced textiles

Abstract

To expand the application range of microencapsulated phase change materials into advanced textiles, we designed and developed a type of photoluminescence phase-change microcapsule system based on an n-eicosane core and a Eu3+-doped CaCO3/Fe3O4 composite shell. This type of functionalized phase-change microcapsules was fabricated by encapsulating n-eicosane in the CaCO3/Fe3O4 composite shell through in-situ precipitation in a Pickering emulsion-templating system, followed by doping Eu3+ on the surface of the CaCO3/Fe3O4 composite shell. The resultant microcapsules show a well-defined core–shell microstructure and regular spherical morphology with a rough surface due to the presence of Eu3+. Introducing Fe3O4 nanoparticles as a light absorber into the CaCO3 shell enhanced the utilization efficiency of solar photothermal energy for the phase-change microcapsules. The fabricated microcapsules not only exhibited a satisfactory thermal regulation capability under a latent heat capacity of over 125 J/g, but also achieved a high photothermal conversion efficiency of 67.6%. Doping Eu3+ into the CaCO3/Fe3O4 composite shell imparted a photoluminescence function to the phase-change microcapsules, resulting in a fluorescence emission at an excitation wavelength of 394 nm. An application investigation of the phase-change microcapsules in advanced textiles was carried out to confirm their contributions to the thermal comfort of human body together with high recognition under the extreme conditions. With excellent solar photothermal conversion, latent heat storage, and photoluminescence performance, the phase-change microcapsules developed by this study exhibit great potential for bifunctional applications of comfort thermal regulation and fluorescent recognition in advanced textiles.