Removal of oil by gelation using hydrophobic silica nanoparticles

Silica nanoparticles are coated by polydimethysiloxane (PDMS) thin film using chemical vapor deposition and the PDMS-coated silica nanoparticles are shown to be highly hydrophobic. These PDMS-coated silica nanoparticles are used for selectively gelating oils in the oil/water mixture, allowing easy separation and removal of oil from water. Hydrophobized silica nanoparticles are shown to be able to gelate rotary pump oil with its mass 15 times higher than that of silica. A gelated mixture of oil and hydrophobized silica is stable and not dispersed in water for 7 days.