Evaluation of Different Mesoporous Silica Supports for Energy Storage in Shape-Stabilized Phase Change Materials with Dual Thermal Responses

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• 作者：Raul鈭扐ugustin Mitran ; Daniela Berger ; Cornel Munteanu ; Cristian Matei
• 刊名：Journal of Physical Chemistry C
• 出版年：2015
• 出版时间：July 9, 2015
• 年：2015
• 卷：119
• 期：27
• 页码：15177-15184
• 全文大小：429K
• ISSN：1932-7455

文摘

The high variability and low heat of fusion of composite shape-stabilized phase change materials is a considerable challenge to their widespread application. Here, we present the synthesis of shape-stabilized phase change materials composed of lauric acid and mesoporous silica with a high heat of fusion through evaporative solution impregnation. Two hexagonal ordered silica with 2.8 and 6.3 nm pores (MCM-41, SBA-15) and two disordered mesocellular foams with 27鈥?4.9 nm spherical pores connected by 10.4鈥?4.9 nm windows are employed. The thermal properties and stability, heat storage efficiency, crystallization, and textural and chemical properties are investigated using differential scanning calorimetry (DSC) analysis, small- and wide-angle X-ray diffraction (XRD), nitrogen adsorption鈥揹esorption isotherms, and optical and electron microscopy, as well as Fourier transform infrared (FTIR) spectroscopy. Mesocellular foam silica (MCF)-based materials with up to 83% wt fatty acid show large latent heat (124 J g^鈥?), almost 90% efficiency with respect to the acid content, and two melting鈥揷rystallization temperature ranges associated with nanoconfined and bulk phases. Up to 53 J g^鈥? enthalpy change for the nanoconfined phase can be obtained. The melting point depression, heat storage efficiency, and the physical state of lauric acid at the mesopore level are correlated with theoretical considerations of thermodynamic and geometric factors, revealing a nonmelting interface layer of one organic molecule thickness. This approach provides a facile methodology to estimate the relevant properties of mesoporous silica phase change materials with useful dual-temperature ranges.