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Morphology Control of Structured Polymer Brushes
Author(s) -
Steenackers Marin,
Küller Alexander,
Ballav Nirmalya,
Zharnikov Michael,
Grunze Michael,
Jordan Rainer
Publication year - 2007
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.200700187
Subject(s) - polymer , materials science , polymerization , monomer , chemical engineering , lithography , polymer chemistry , photopolymer , layer (electronics) , layer by layer , template , nanotechnology , composite material , optoelectronics , engineering
Abstract The surface‐initiated photopolymerization (SIPP) of vinyl monomers on structured self‐assembled monolayers, as defined by two‐dimensional (2D) initiator templates for polymer growth, is investigated. The 2D templates are prepared by electron‐beam chemical lithography (EBCL) of 4′‐nitro‐4‐mercaptobiphenyl (NBT) and chemical conversion to an asymmetric azo initiator (4′‐azomethylmalonodinitrile‐1,1′‐biphenyl‐4‐thiol). Ex situ kinetic studies of the SIPP process reveal a linear increase in the thickness of the polymer layer with the irradiation/polymerization time. The effect of the applied electron dosage during the EBCL process upon the final thickness of the polymer layer is also studied. The correlation between the electron‐induced conversion of the 4′‐nitro to the 4′‐amino group and the layer thickness of the resulting polymer brush indicates that the polymer‐brush grafting density can be directly controlled by the EBCL process. NBT‐based template arrays are used for the combinatorial study of the influence of the lateral structure size and the irradiation dosage on the morphology of the resulting polymer‐brush layer. Analysis of the array topography reveals the dependence of the thickness of the dry polymer layer on both electron dosage and structure size. This unique combination of EBCL as a lithographic technique to locally manipulate the surface chemistry and SIPP to amplify the created differences allows the preparation of defined polymer‐brush layers of controlled morphologies.