Weak polyelectrolyte brush arrays fabricated by combining electron-beam lithography with surface-initiated photopolymerization

TitleWeak polyelectrolyte brush arrays fabricated by combining electron-beam lithography with surface-initiated photopolymerization
Publication TypeJournal Article
Year of Publication2006
AuthorsM Kaholek, WK Lee, J Feng, B LaMattina, DJ Dyer, and S Zauscher
JournalChemistry of Materials
Volume18
Issue16
Start Page3660
Pagination3660 - 3664
Date Published08/2006
Abstract

We present a simple "top-down/bottom-up" strategy to fabricate nano- and micropatterned polymer brush arrays composed of pH- and salt-sensitive, weak polyelectrolyte copolymers [poly(N-isopropy-lacrylamide-co- methacrylic acid, 3:1, poly (NIPAAM-co-MAA)]. In our approach, a silicon surface is first patterned with gold, using "lift-off' electron-beam lithography ("top-down"), and the resulting pattern is then amplified by surface-initiated photopolymerization by conventional, UV-light-induced free radical polymerization ("bottom-up") from an immobilized 2,2′-azobisisobutyronitrile (AIBN) type initiator. The use of pH- and ionic-strength-sensitive comonomers in the copolymer brush enables large, externally triggered conformational changes of the micro- and nanopatterned polymer brushes. We observed that the height of nanopatterned ionized polymer brushes increases with increasing feature size of the pattern. The design and fabrication of surfaces with conformationally switchable, patterned polymeric structures is important for sensing and actuation applications on the micro- and nanoscales. © 2006 American Chemical Society.

DOI10.1021/cm060276r
Short TitleChemistry of Materials