A novel thermal-insulating film incorporating microencapsulated phase-change materials for temperature regulation and nano-TiO2 for UV-blocking

• A novel thermal-insulating film is fabricated for temperature regulation.
• The latent heat of the films with 6 wt% microcapsules achieves 8.96 J/g.
• The obtained films maintain good thermal cycling stability after 100 cycling.
• The temperature of the shielding space can be kept in 25–28 °C for 3298 s.
• The UV-blocking property of the films with nano-TiO2 is highly improved.

Phase-change materials (PCMs) have promising applications in the fields of solar energy storage, energy conservation in buildings, thermal insulation, and thermal regulation. In this study, novel multifunctional composite films were prepared via a thermosetting process using poly(vinyl chloride) (PVC) as a film matrix, microencapsulated PCMs (micro-PCMs) as a temperature-regulating additive and TiO2 nanoparticles (nano-TiO2) as a UV-blocking additive. The latent heat of the film fabricated with 6 wt% micro-PCMs and 6 wt% nano-TiO2 is 9.226 J/g. The film also shows high thermal stability, with no obvious change in thermal performance after 100 heating–cooling cycles. The temperature of a space enclosed by the film fabricated with 6 wt% micro-PCMs and 6 wt% nano-TiO2 can be controlled in the range 25–28 °C for 3298 s. The composite films exhibit a significantly decreased UV transmittance due to the UV absorption of nano-TiO2. Furthermore, the thermal conductivity of the sample fabricated with 6 wt% micro-PCMs and 6 wt% nano-TiO2 is 0.2356 W/(m K), which is comparable with that of a pure PVC film. These findings indicate that the novel thermal-insulating film is promising for use in energy-efficient building and automobile applications.