Abstract: This study is mainly focused on the fabrication of nano-SiO₂ as an inorganic shell material encapsulated an organic thermochromic (TC) core material comprising of either the (i) three-component as-synthesized blue dyes [BDTCM@SiO₂] or (ii) off-the-shelf (commercial) black dyes [CDTCM@SiO₂]. Both the SiO₂ encapsulated thermochromic systems have successfully demonstrated the color transition at around 31 oC. 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 wt% 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@SiO₂ are below 100 nm, whereas, the CDTCM@SiO₂ samples exhibited the mean particle sizes varied in the range of 100-1000 nm. The endothermic phase transition due to melting and in general, the thermal stabilities of these SiO₂ encapsulated TCMs have been explored for the purpose of deploying these systems for thermal energy savings or storage applications.

Key words: Thermochromic materials, nanoparticles, chromaticity, transition temperature, enthalpy, BDTCM@SiO₂, CDTCM@SiO₂.

Cite: Abdullatif Hakami, Mingyang Huang, Sharan Indrakar, Ashwini Krishnegowda, Elias Stefanakos, Sesha Srinivasan, "Microencapsulation of the as-Synthesized and off-the-Shelf Thermochromic Dyes by Nanosized SiO₂ for Thermal Energy Savings Applications," International Journal of Materials Science and Engineering, Vol. 8, No. 4, pp. 105-117, December 2020. doi: 10.17706/ijmse.2020.8.4.105-117

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