부산대학교 도서관

Porous glass with 1–3 nm pore size was prepared. A trithiocarbonates-type chain-transfer agent was introduced onto the surface of the porous glass. Poly(N-isopropylacrylamide) (PNIPAM) was grafted onto the surface of the porous glass using combination of grafting-from and reversible addition-fragmentation chain transfer (RAFT) controlled radical polymerization techniques. PNIPAM shows a lower critical solution temperature (LCST ≈ 32°C) in water. Below this LCST, the pore valve was closed, because the PNIPAM grafted chains expand due to hydration. Above the LCST the pore valve opened, because the PNIPAM graft chains shrunk due to dehydration. Although low molecular weight compounds can permeate through PNIPAM-grafted porous glass above the LCST in water, the compounds cannot permeate through the porous glass below the LCST. PNIPAM-grafted porous glass can control on-off of permeation by changing temperature.