Preparation and investigation on multi-temperature silica/octadecane phase change materials

Abstract

With the rapid growth of resource depletion, heat storage materials play a vital role in sustainable development. However, as a kind of heat storage material, phase change material (PCM) leaks easily when used, so anti-leak measures are crucial. In this study, microencapsulation phase change materials (MPCMs) were prepared by emulsifying first and then crosslinking, in which tetraethyl orthosilicate (TEOS) was used as the shell coating precursor, octadecane as the core and sodium dodecyl sulfonate (SDS) as the emulsifier. The grafted objects of Si–O bonds in TEOS were adjusted through different ratios of SDS/octadecane. The results showed that when the mass ratio of SDS/octadecane is 0.067, SDS is hydrolyzed to lauryl alcohol under acidic conditions and grafted with silica, and the phase transition temperature is − 20 °C. SDS gradually changed from graft to adhere with octadecane through sulfonic acid bond when the mass ratio of SDS/octadecane increased. Si–O bonds combine octadecane with sulfonic acid bonds through van der Waals forces and the indirect branches of Si–O bonds form an inorganic silica shell. When the mass ratio of SDS/octadecane is 0.15, the phase transition temperature was 23 °C and the phase transition enthalpy was 111.9 J g⁻¹. The obtained silica/octadecane MPCMs have small diameter, good thermal stability and the phase change enthalpy remains stable after 500 cycles, and the composite materials blended with polyvinyl alcohol also have good thermal properties. It is expected to be applied in the field of heat management textiles.