| 초록 |
The orientations of block copolymer thin films were studied on phenylalkyl self-assembled monolayer (SAM) deposited substrates. Two different phenylalkylsiloxane self-assembled monolayers, from phenylethyltrichlorosilane (PETS) and phenylundecyltrichlorosilane (PUTS), were deposited on Si wafers. Then, Polystyrene-block-poly(methyl methacrylate) (PS-b-PMMA) with lamellar and cylindrical structure were spin-coated on PETS and PUTS deposited substrates and annealed at 180℃ in vacuum. To characterize the SAMs contact angle measurement, Reflection-Absorption Infrared Spectroscopy and Near Edge X-ray Absorption Fine Structure were used and orientations of block copolymer films were investigated on the basis of Atomic Force Microscope (AFM). Also, to compare the orientation of PS-b-PMMA on phenyl SAMs with that of alkyl SAMs, alkyl SAMs from decyltrichlorosilane(DTS) and prophyltrichlorosilane(PTS) - with similar methylene groups - were deposited in the same way and PS-b-PMMA were spin-coated on them. Parallel orientation was formed when the molecular weight of PS-b-PMMA was relatively small, in contrast, perpendicular orientation was occurred on relatively high molecular weights PS-b-PMMA for both lamellar and cylindrical block copolymers. In particular, perpendicular domains lasted longer on PUTS SAM which had longer alkyl chains than on PETS SAM. Dewetting of polymer, However, was occured on DTS deposited substrate even before annealing. Based on these results, the structure and functional group of SAMs affects the orientation of block copolymers. |
