Microencapsulated phase change materials (MicroPCMs) with TiO2-modified natural polymer shell and macrocapsules containing MicroPCMs for thermal energy storage and UV-shielding

Micro-encapsulated/macro-encapsulated phase change materials (Micro/MacroPCMs) are attractive environmental energy materials since they can be integrated into building materials, textile fabrics and heat-insulating materials to give their solar energy storage capacities and improve their temperature adjustment abilities. An innovative set of Micro/MacroPCMs has been designed using natural polymers, showcasing prowess in solar energy storage and UV protection. The eco-friendly bifunctional MicroPCMs are made up of paraffin as core and titanium dioxide (TiO2)-modified chitosan (CS) as shell. Their energy efficiency was elevated using a double emulsion technique. Alginate (ALG), an anionic polysaccharide, was selected as the matrix of the MacroPCMs to provide an enhanced combination with the cation polysaccharide CS shell. The surfaces and structures of the Micro/MacroPCMs were observed through SEM and image measurement (IM). Their chemical profile was deciphered using FTIR and XRD. Ultraviolet–visible spectrophotometry evaluated their UV resistance. DSC, TGA, and infrared thermography delved into their thermal attributes, while a texture analyzer revealed the mechanical strength of the MacroPCMs. The introduction of TiO2 resulted in a greater effective enthalpy and thermal stability. The energy storage ability of the MicroPCMs was further improved by using a double emulsification system. Notably, MicroPCMs crafted with TiO2-infused CS using the double emulsion approach stood out, boasting an impressive PCM content of 81.3 %, a melting enthalpy of 125.5 J/g, and commendable UV and thermal regulation capacities. With their robust thermal performance and mechanical resilience, these eco-friendly difunctional Micro/MacroPCMs emerge as prime contenders in solar energy conservation and temperature control applications. •Paraffin was microencapsulated with titanium dioxide (TiO2)-modified chitosan shell.•Double emulsion method improved the encapsulation efficiency.•TiO2-modified MicroPCMs possess UV-shielding and temperature-regulated function.•MacroPCMs containing MicroPCMs in alginate display better compressive strength.