Chemically cross-linked gel storage for fuel to realize evaporation suppression

High-energy density liquid fuels are commonly used to operate combustors such as rockets, gas turbines, automotive engines, and boilers to make an energy transformation. To prevent a serious incident such as an explosion or a fire disaster, we have recognized practical issues of the liquid fuels that are safety and stability during transportation and storage, evaporation rate, and burning rate constant. In this experiment, ethanol is used as a liquid fuel and is retained on chemically cross-linked poly(N-isopropylacrylamide) (PNIPPAm) gel to use it as a polymeric gel storage for liquid fuels. In general, because the cross-linking structure of chemical gels is formed by covalent bonding, it is more stable than physical gels for a thermodynamic change such as temperature. The evaporation rate of the polymeric gel storage to suppress evaporating the ethanol is investigated. We finally demonstrate to obtain burning rate constants based on a changing mass of the polymeric gel storage during combustion. By demonstrating the polymeric gel storage combustion, we revealed existence of the d² law in a droplet combustion.