Title:Phase Change Materials Based on Mesoporous Silica
VOLUME: 22 ISSUE: 27
Author(s):Raul - Augustin Mitran*, Daniela Berger and Cristian Matei
Affiliation:University , University
Keywords:Phase change, mesoporous silica, shape-stabilized, form stable, nanoconfinement, heat storage, nanocomposites.
Abstract:Thermal energy can be stored as sensible or latent heat. Phase change materials
(PCMs) use latent heat storage, offering great energy density over a limited temperature
range. Organic materials, such as paraffins, fatty acids, polymers, sugar alcohols and their
eutectic mixtures can be used as PCMs for applications near room temperature, due to their
high liquid-solid enthalpy. Inorganic salts and salts hydrates can also function as PCMs,
although most of them suffer from incongruent crystallization. Pure PCMs exhibit some
disadvantages, such as leakage, decreased thermal transfer and storage capacity during use,
arising from their large change in molar volume upon phase transition. These drawbacks
can be alleviated by impregnation in high porosity matrices. A promising class of porous
matrices is represented by Mesoporous Silica Nanomaterials (MSN). MSN offer high pore
volume and surface area, often in excess of 1 cm3/g and 1000 m2/g, respectively, monodisperse pores, high
chemical and thermal stability and ease of tailoring their textural, morphological and surface properties through
chemical synthesis.
To date, the studies on nanocomposites phase change materials using mesoporous silica matrices have not been
reviewed. The current review focuses on the various strategies for obtaining the MSN matrices and PCMs,
their properties and the fundamental aspects pertaining to the difference in thermal properties between nanoconfinement
in MSN and bulk. The monodisperse pores in the 2 – 50 nm range give rise to nanoconfinement
effects, such as decreased melting and crystallization points with respect to bulk phases, hysteresis between
melting and crystallization and existence of an interface, liquid-like layer between the silica surface and PCM
molecules. The nanoconfinement effects on the PCM properties are discussed and insight into the materials and
their applications is provided.
