New approach for sol–gel synthesis of microencapsulated n-octadecane phase change material with silica wall using sodium silicate precursor

Fang He, Xiaodong Wang and Dezhen Wu

Energy, 2014, vol. 67, issue C, 223-233

Abstract: A new silica encapsulation technique toward n-octadecane PCM (phase change material) was developed through sol–gel synthesis using sodium silicate as a silica precursor. Fourier transform infrared spectra confirm the chemical composition of the synthesized microcapsules, and wide-angle X-ray scattering patterns indicate good crystallinity for the n-octadecane inside silica microcapsules. Scanning electric micrographs demonstrate that the microencapsulated n-octadecane obtained at pH 2.95∼3.05 presents a perfect spherical morphology and a well-defined core–shell microstructure. Because the pH value of reaction solution determines the silica condensation rate and, thus, influences the balance between the self-assembly and polycondensation of silica precursors on the surface of n-octadecane droplets, the microcapsules could achieve a smooth and compact surface at pH 2.95∼3.05. The microencapsulated n-octadecane also exhibits good phase change performance and achieves a high encapsulation rate and high encapsulation efficiency in this synthetic condition. The encapsulation of n-octadecane with compact and thick silica wall can impart a high thermal conductivity and a good anti-osmosis property to the microcapsules, and can also improve the thermal stability of the microcapsules by preventing inside n-octadecane from thermally evaporating. Owing to the easy availability and low cost of sodium silicate, this synthetic technique indicates a high feasibility in industrial manufacture for the microencapsulated PCMs with inorganic walls.

Keywords: Microencapsulated n-octadecane; Silica wall; Phase change performance; Microstructure; Thermal conductivity; Phase change performance (search for similar items in EconPapers)
Date: 2014
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (29)

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Persistent link: https://EconPapers.repec.org/RePEc:eee:energy:v:67:y:2014:i:c:p:223-233

DOI: 10.1016/j.energy.2013.11.088

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