Microencapsulation of Thermochromic Material by Silicon Oxide Nanoparticles

This study is mainly focused on the fabrication of SiO 2 as an inorganic shell material encapsulated an organic thermochromic (TC) core material comprises of either the (i) three-component as-synthesized blue dyes [BDTCM@SiO 2 ] or (ii) off-the-shelf (commercial) black dyes [CDTCM@SiO 2 ]. Both the SiO 2 encapsulated thermochromic systems have successfully demonstrated the color transition at around 31 °C. For the three-component thermochromic microcapsules, we have used the crystal violet lactone (CVL) as a leuco dye, bisphenol-A (BPA) as a color developer, and 1-tetradecanol (TD) as a solvent. Different ratios of the thermochromic dye and the metal oxide were prepared to examine the effect of the core@shell ratio on the microstructural and thermal properties of the encapsulated microcapsules. The mean particles sizes of the BDTCM@SiO 2 are below 100 nm, whereas, the CDTCM@SiO 2 samples exhibited the mean particle sizes varied in a range of 100-1000 nm. The endothermic phase transition due to melting and in general, the thermal stabilities of these SiO 2 encapsulated TCMs have been explored for the purpose of deploying these systems for thermal energy savings or storage applications.