To apply mobile crystalline material 41 (MCM-41), which has a larger specific surface area than many other nanoporous silicas, for energy absorption, chlorotrimethylsilane treatment is performed to adjust the structure of inner surfaces of nanopores. As the treatment time is sufficiently long, the pore surface can be changed from hydrophilic to hydrophobic, leading to an energy absorption efficiency a few times higher than previously developed nanoporous-material-functionalized liquids. A strong effect of addition of electrolyte on infiltration pressure is observed.