Authors Romeis, D. ; Sommer, J.-U.
Title Conformational switching of modified guest chains in polymer brushes
Date 05.08.2013
Number 38983
Abstract Using a numerical quasi off-lattice self-consistent field method which describes heterogeneous chains of spherical monomers we study the case of a densely grafted polymer brush with a fraction of free chain ends being replaced by a modified end-group differing in size and solvent selectivity. We can confirm the observation from molecular dynamics simulations that upon changing the solvent conditions, a switching in location of end-groups which are bigger than monomers from a state “exposed” to the solvent (on the top of the brush) to a “hidden” state (inside the brush) takes place. Our numerical method allows a detailed study of the switching effect as a function of the relevant parameters, such as grafting density, chain length, size of end-groups and their volume fraction. We find that the switching effect is enhanced for long chains, low fractions of modified chains, and big end-groups. We consider the case of low fraction of modified chains in more detail using a test chain method. Here, we explore the optimal grafting density as a function of the size of the end-groups, where the switching is most sensitive. These values can be in the experimental range for end-groups which are at least 3–4 times bigger than the monomers. The end-groups can be realized by attaching nano-particles to the last monomer of a brush-chain. © 2013 AIP Publishing LLC
Publisher Journal of Chemical Physics
Citation Journal of Chemical Physics 139 (2013) 044910 (11 pages)

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