Poly-N-Isopropyl-acrylamide/acrylic acid copolymers for the generation of nanostructures on mica surfaces and as hydrophobic host systems for the porin mspa from mycobacterium smegmatis

Academic Article

Abstract

  • The work presented here aims at utilizing poly-N-isopropyl-acrylamide/ acrylic acid copolymers to create nanostructured layers on mica surfaces by a simple spincasting procedure. The average composition of the copolymers determined by elemental analysis correlates excellently with the feed composition, indicating that the radical polymerization process is statistical. The resulting surfaces were characterized by atomic force microscopy (magnetic ac mode) at the copolymer-air interface. Postpolymerization modification of the acrylic acid functions with perfluoro-octyl-iodide decreased the tendency toward spontaneous formation of nanopores. Cross linking of individual polymer chains permitted the generation of ultraflat layers, which hosted the mycobacterial channel protein MspA, without compromising its channel function. The comparison of copolymers of very similar chemical composition that have been prepared by living radical polymerization and classic radical polymerization indicated that differences in polydispersity played only a minor role when poly-N-isopropyl- acrylamide/acrylic acid copolymers were spincast but a major role when copolymers featuring the strongly hydrophobic perfluoro-octyl labels were used. The mean pore diameters were 23.8 ± 4.4 nm for P[(NIPAM) 95.5-co-(AA) 4.5] (PDI, polydispersity index = 1.55) and 21.8 ± 4.2 nm for P[(NIPAM) 95.3-co-(AA) 4.7] (PDI ) 1.25). The depth of the nanopores was approximately 4 nm. When depositing P[(NIPAM) 95-co-(AA) 2.8-AAC8F 17 2.2] (PDI = 1.29) on mica, the resulting mean pore diameter was 35.8 ± 7.1 nm, with a depth of only 2 nm. © 2009 American Chemical Society.
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    Digital Object Identifier (doi)

    Author List

  • Gamage P; Basel MT; Lovell K; Pokhrel MR; Battle D; Ito T; Pavlenok M; Niederweis M; Bossmann SH
  • Start Page

  • 16485
  • End Page

  • 16494
  • Volume

  • 113
  • Issue

  • 37