Authors Horechyy, A. ; Nandan, B. ; Zafeiropoulos, N.E. ; Jehnichen, D. ; Göbel, M. ; Stamm, M. ; Pospiech, D.
Title Nanoparticle directed domain orientation in thin films of asymmetric block copolymers
Date 02.09.2014
Number 43063
Abstract We investigated the thin film morphology of two different asymmetric block copolymers (BCP), polystyrene-block-poly(4-vinylpyridine) (PS-b-P4VP) and poly(n-pentyl methacrylate)-block-poly(methyl methacrylate) (PPMA-b-PMMA), loaded with pre-synthesized iron oxide nanoparticles (NP). The chemical composition of the BCP constituents determines the strength of the interaction between polymer chains and nanoparticles. In the case of NP/PS-b-P4VP system, the nanoparticles interact preferentially with the P4VP block and hence localize selectively in the P4VP cylindrical microdomains. However, for the NP/PPMA-b-PMMA system, the nanoparticles have no significant preference for the copolymer blocks and segregate at the polymer/substrate interface. Interestingly, this changes the effective substrate surface energy and hence leads to a remarkable change in domain orientation from parallel to perpendicular with respect to the substrate. These results clearly demonstrate the importance of both enthalpic and entropic factors which determine spatial distribution of NP in BCP films and influence domain orientation.
Publisher Colloid and Polymer Science
Citation Colloid and Polymer Science 292 (2014) 2249-2260
Tags block copolymer self-assembly domain orientation nanoparticles thin polymer films

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