TY  - JOUR
A1  - Kopyshev, Alexey
A1  - Galvin, Casey J.
A1  - Genzer, Jan
A1  - Lomadze, Nino
A1  - Santer, Svetlana
T1  - Opto-mechanical scission of polymer chains in photosensitive diblock-copolymer brushes
T2  - Langmuir
N2  - In this paper we report on an opto-mechanical scission of polymer chains within photosensitive diblock-copolymer brushes grafted to flat solid substrates. We employ surface-initiated polymerization of methylmethacrylate (MMA) and t-butyl methacrylate (tBMA) to grow diblock-copolymer brushes of poly(methylmethacrylate-b-t-butyl methacrylate) following the atom transfer polymerization (ATRP) scheme. After the synthesis, deprotection of the PtBMA block yields poly(methacrylic acid) (PMAA). To render PMMA-b-PMAA copolymers photosensitive, cationic azobenzene containing surfactants are attached to the negatively charged outer PMAA block. During irradiation with an ultraviolet (UV) interference pattern, the extent of photoisomerization of the azobenzene groups varies spatially and results in a topography change of the brush, i.e., formation of surface relief gratings (SRG). The SRG formation is accompanied by local rupturing of the polymer chains in areas from which the polymer material recedes. This opto-mechanically induced scission of the polymer chains takes place at the interfaces of the two blocks and depends strongly on the UV irradiation intensity. Our results indicate that this process may be explained by employing classical continuum fracture mechanics, which might be important for tailoring the phenomenon for applying it to poststructuring of polymer brushes.
Y1  - 2013
UR  - https://publishup.uni-potsdam.de/frontdoor/index/index/docId/34590
SN  - 0743-7463
VL  - 29
IS  - 45
SP  - 13967
EP  - 13974
PB  - American Chemical Society
CY  - Washington
ER  -