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Authors
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Minko, S. ; Luzinov, I. ; Luchnikov, V. ; Müller, M. ; Patil, R.D. ; Stamm, M.
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Title
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Bidisperse Mixed Brushes: Synthesis and Study of Segregation in Selective Solvent
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Date
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06.10.2003
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Number
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11222
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Abstract
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We prepare a series of mixed brushes of two incompatible polymers, polystyrene (PS) andpoly(2-vinylpyridine) (P2VP) grafted by end groups to Si wafers from carboxyl-terminated P2VP (<I>M</I><SUB>W</SUB>(P2VP) 42 kg/mol) and carboxyl-terminated PS. The molecular mass of PS ranged from 2.98 to 75 kg/mol. The mixed brushes are bidisperse (asymmetric) with respect to the difference of molecular mass ofP2VP and PS while the polydispersity of PS and P2VP is narrow. We expose the mixed brushes to selectivesolvents (toluene for PS and ethanol for P2VP). The morphology and surface chemical composition areinvestigated using scanning probe microscopy and contact angle measurements. For small chain lengthasymmetry, the brushes exhibit lateral and perpendicular segregation, and the structure depends on thesolvent quality. Upon increasing the molecular weight asymmetry, we encounter the transition from amorphology of laterally segregated domains to a layered (sandwich-like) structure. The location of thistransition can be tuned by changing the solvent selectivity. We find qualitative agreement betweenexperiments and self-consistent-field calculations.
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Publisher
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Macromolecules
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Wikidata
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Citation
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Macromolecules 36 (2003) 7268-7279
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DOI
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https://doi.org/10.1021/ma034160h
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Tags
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monte-carlo-simulation self-assembled monolayers grafted polymer-chains neutron reflectivity force microscopy diblock copolymers microphase separation block-copolymers density profile layers
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