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CPP: Fachverband Chemische Physik und Polymerphysik
CPP 3: Interfaces and Thin Films I
CPP 3.4: Vortrag
Montag, 14. März 2011, 11:15–11:30, ZEU 160
Approach to polymer brushes of spherical monomers — •Dirk Romeis1,2, Holger Merlitz1,3, and Jens-Uwe Sommer1,2 — 1Leibniz-Institut für Polymerforschung, 01069 Dresden — 2TU Dresden, Fachbereich Physik, 01062 Dresden — 3Department of Physics and ITPA, Xiamen University, Xiamen 361005, P. R. China
Recent experiments [1] for the creation of polymer brushes achieved considerable high grafting densities (σ≥ 1/nm2 ) and subsequently chain stretchings up to 70−90%. In this range the behavior can no longer be approximated using the Gaussian chain model. Furthermore MD simulations [2] of brushes of densely grafted chains revealed significant instabilities of the brush surface upon slight variations of individual chains/chain ends. Analytical SCF approach for a polymer brush of spherical monomers [3] is not applicable to study these effects as it fully neglects fluctuations. We present a modified Scheutjens-Fleer method to account for a spherical shape of the monomers, compare the results with other approaches [2],[3] and give a quantitative analysis of the observed surface instabilities, which entail the behavior of a phase transition. [1] Devaux C. et. al. [Macromolecules 38 4296, 2005]. [2] Merlitz H. et. al. [Macromolecules 41 5070, 2008]. [3] Biesheuvel M. et. al. [Macromolecules 41 6254, 2008].