More importantly, micro encapsulation would not have an effect on the properties of core materials, on condition that proper shell material and getting ready techniques are chosen. Therefore, micro encapsulation is extremely suitable for improving the steadiness of thermochromic mixtures. After being encapsulated, the thermal stability and therefore the resistances to leaching, acid and solvent for thermochromic materials would be considerably enhanced, which obviously extends their application fields. As a result, the bulk of thermochromic materials are produced in the form of micro capsule powders or micro capsule suspensions. The micro encapsulated particles are in solid powder form which is much more convenient to handle with than that of liquid.
The essence of micro encapsulation is that a uniform and stable layer of shell material covers the core material by physical or chemical reactions. The production of micro capsules began in Thirties and boomed in 1970s. According to the forming mechanism and condition of shell, micro encapsulation will be divided into 3 categories, specifically physical, chemical and physico-chemical strategies.
Micro encapsulated phase change materials have been widely used in electronics cooling, thermal regulation textile, energy efficiency construction materials, healthcare & personal care, consumer goods. Bio wax and normal paraffin are two common PCMs as cores, inorganic silica or high polymer material such as PMMA are used as shell materials. By adopting micro encapsulation technology, the liquid PCM can be protected and separated in the shell. Thus the solid-liquid material is turned to solid-solid material by mciro encapsulation process. The MPCM is more easily handled and its application range has been extended.
