Optimization of a silicon-based microencapsulation technology of phase change material without organic solvents

Abstract

Phase change microcapsules (MPCM) have significant advantages, such as fast thermal response and low leakage rate, which can be widely used in construction, textile, and electric power fields. However, the existing microcapsule preparation process has high costs and complicated steps, which limits its popularization and application. This paper reports a de-organic reform of the in-situ polymerization method for the fabrication of MPCM. The aqueous phase (solvent) consisted of pure deionized water and surfactant instead of conventional partial or pure organic solvents such as ethanol and acetamide. Taking the type and content of surfactant, homogenization speed, solvent ratio and core-shell ratio as the research variables, the optimal fabrication scheme of silicon-based MPCM in an alkaline environment was confirmed. The results showed that the Pa@SiO2 microcapsules prepared by pure inorganic solvents had great shape stability to prevent phase change material leakage and great temperature regulation performance when appropriate amount of hexadecyl trimethyl ammonium bromide was the surfactant and 3-Aminopropyltriethoxysilane was the silane coupling agent. More importantly, it has high heat storage capacity of 191.5 J/g due to its excellent encapsulation ratio of 76.4 %. Therefore, the fabrication method without organic solvent can simplify the fabrication process and greatly reduce the fabrication cost while ensuring excellent thermal properties of microcapsules, especially the outstanding heat storage capacity, which shows great application prospects in terms of microcapsule large-scale production.