Thermochromic microencapsulated phase change materials for cold energy storage application in vaccine refrigerator

The development of pharmaceutical cold chain logistics calls for thermochromic microencapsulated phase change materials (TC-MPCMs) to fit the demand of temperature indication and low temperature (2–8 °C) cold storage. In this study, TC-MPCMs for low temperature were constructed by encapsulating crystal violet lactone (CVL), bisphenol A (BPA) and n-tetradecane & n-dodecanol (aliphatic compound) binary system into melamine-formaldehyde (MF) resin. The effects of emulsifier type, n-dodecanol content, and core/shell ratio on the performance of TC-MPCMs were investigated. Results indicate that TC-MPCMs with SMA: gelatin ratio of 2:1 exhibit the best morphology and uniform dispersion, with particle size distribution between 4.5 μm and 19.5 μm. TC-MPCMs with 25 wt% 12OH and core/shell of 1.85 demonstrate excellent property in terms of the encapsulation efficiency, melting enthalpy and color difference, which are 67.80 %, 169.90 J/g and 23.39, respectively. Synthesized TC-MPCMs present outstanding thermal durability during 100 thermal cycles and have an appreciable thermal stability at temperature not exceeding 96 °C. The vaccine refrigerator was designed which can maintain a low temperature (2–8 °C) for 12.8 min.