Authors Mäkinen, R. ; Ruokolainen, J. ; Ikkala, O. ; de Moel, K. ; ten Brinke, G. ; De Odorico, W. ; Stamm, M.
Title Orientation of Supramolecular Self-Organized Polymeric Nanostructures by Oscillatory Shear Flow
Date 19.12.2000
Number 9654
Abstract Macroscopic orientation of self-organized supramolecular polymeric materials has beendemonstrated by oscillatory shear flow using in-situ small-angle X-ray scattering (SAXS). In the casewhen a homopolymer poly(4-vinylpyridine) and pentadecylphenol molecules are stoichiometricallycomplexed to form comb copolymer-like supermolecules, the self-organized lamellar local structures alignparallel when sheared below the order-disorder transition temperature at 56 <IMG SRC="/images/entities/deg.gif">C using 0.5 Hz frequencyand 100% strain amplitude. Therefore, the hydrogen bonds between the phenolic and pyridine groupsare strong enough to withstand the applied flow. In the case of a diblock copolymer of polystyrene andpoly(4-vinylpyridine) stoichiometrically complexed with pentadecylphenol molecules to form the supermolecules, the self-organization yields lamellar-<I>within</I>-lamellar local structure near room temperature.The larger lamellar diblock copolymer structure showed a parallel orientation relative to the shearingplates upon shearing at 125 <IMG SRC="/images/entities/deg.gif">C (i.e., above the order-disorder transition of the short length scale combcopolymer-like structure) with initially 0.5 Hz and finally 1 Hz, both at 50% strain amplitude. On cooling,the short length sca<br />le lamellar structure, consisting of poly(4-vinylpyridine) block and pentadecylphenol,is formed inside the layers of the comb copolymer-like material in perpendicular orientation.
Publisher Macromolecules
Citation Macromolecules 33 (2000) 3441-3446
Tags lamellar diblock copolymer block-copolymers induced alignment length scales order dynamics systems morphologies transition complexes

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