Plasma-induced Interfacial Crosslinking of Liquid Polydimethylsiloxane Films and Their Organic Solvent Permeation Performance

Polydimethylsiloxane (PDMS) has been extensively studied as a separation membrane due to the high permeability of gases and organic solvents. Here we report 60-nm-thick PDMS membranes prepared by interfacial crosslinking of PDMS solution using N2-plasma. It was found that the presence of hydrocarbon in PDMS accelerates the crosslinking reaction, giving mechanically tough ultrathin membranes with swellable pores of 4 to 5 nm. Molecular modelling calculation suggested that dissociation of carbon-silicon bonds is the major pathway of crosslinking reaction. Robust and ultrathin membranes were prepared from liquid polydimethylsiloxane (PDMS) films containing hexane or decane by means of interfacial crosslinking using N2-plasma. Their organic solvent permeability and filtration performance were widely changed with irradiation conditions. The crosslinked membranes have a network structure that can perfectly reject 5-nm Au nanoparticles.