Molecular Dynamics Simulation of Intramolecular Cross-Linking of BCB/Styrene Copolymers
JW Liu and ME Mackay and PM Duxbury, MACROMOLECULES, 42, 8534-8542 (2009).
Polymeric nanoparticles can be manufactured by intramolecular cross- linking of benzocyclobutene (BCB)/styrene copolymers. We study this process by extensive molecular dynamics simulations of both atomistic and coarse-grained models. It is found that the rate of intramolecular cross-linking is close to quadratic in the number of unlinked cross- linkers, namely BCB monomeric units, while the completeness of the reaction is affected by the steric hindrance of the cross-linked polymer. An equation incorporating both of these processes yields a good agreement with simulation data. A rigidity effect is identified when the cross-linkers account for more than about 60% of a precursor BCB/styrene copolymers shown little dependence on their cross-linker concentrations, and a relatively large of BCB monomeric units are left unreacted ineach polymer. In addition, a temperature series study is performed on the intramolecular cross-linking of freely jointed of cross-linking and the structure of a cross-linked polymer. A power law relation is found beetween the radius of gyration of the polymer and the chemical distance density, in both FJC samples and BCB/styrene copolymers
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