| Abstract
| - Patterned films of a low-polydispersity polymer densely end-grafted on a silicon substratewere fabricated for the first time by the combined use of the Langmuir−Blodgett (LB) and the surface-initiated atom transfer radical polymerization (ATRP) techniques: a blend monolayer of 2-(4-chlorosulfonylphenyl)ethyltrimethoxysilane (CTS: ATRP initiator) and n-octadecyltrimethoxysilane (OTS: noninitiator) was immobilized on a silicon wafer by the LB technique, and then the ATRP of methylmethacrylate was carried out on the modified wafer in the presence of the Cu/ligand complexes. Atomicforce microscopic studies revealed that the CTS/OTS blend was immiscible and phase-separated intotwo monolayer phases: most OTS molecules aggregate with each other, forming a condensed-typemonolayer domain with CTS molecules excluded from there almost perfectly, and the remaining OTSmolecules are incorporated in the matrix region. This 2-dimensionally phase-separated structure wassuccessfully amplified by the controlled growth of a high-density graft layer only on the matrix phase ofCTS as a main component. The amplification by the ATRP technique was characterized by a sharpboundary between the grafted and ungrafted domains; as a measure of the spatial resolution, the boundarysharpness Δw was evaluated to be ca. 100 nm. The domain size in the phase-separated structure wasindependent of the mole fraction of CTS, while it could be changed by changing the pH of the subphasewater: namely, the higher was the pH, the larger was the domain size. It was deduced that a change inpH of the subphase water gave rise to a change in the hydrolysis rate of the methoxysilyl groups intosilanol groups and hence a change in the rate of condensation of the silanol groups into domains.
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