Preparation of aerogel-eicosane microparticles for thermoregulatory coating on textile

Aerogel/eicosane microparticles were prepared by dispersing nanoporous silica aerogel powder in a liquid of phase change material (PCM), eicosane. Melt-infiltration (M), solvent-dissolving (D) and combined melt-dissolving (MD) for particle dispersion were investigated. Differential Scanning Calorimetric thermograph indicated that microparticle M has maximum heat capacity of 198 J/g whereas the heat capacity of microparticles D and MD was found to be 139 J/g and 144 J/g, respectively. FT-IR and SEM analyses of the microparticles revealed that the eicosane infiltrated and coated the fine aerogel particles but the microparticles still remained in the powder form. The nanoporous aerogel structure held the infiltrated eicosane while the ultra-high specific surface area of silica aerogel kept the surrounding eicosane in situ by surface tension. Infrared thermal imaging showed that the eicosane did not drip out from the microparticles even at 120 °C, whereas the pure PCM completely changed phase to fluid when heated. The developed microparticles provide ease of coating application in room temperature for thermal protective textiles. The coated fabric showed significantly improved thermal resistance over the speculated phase transition period of the PCM. This opens up the opportunity for the developed microparticles to be utilised as a thermal protective coating additive in a wide temperature range without melting or dripping out from the applied substrates.