Lamellar phases and microemulsions in model ternary blends containing amphiphilic block copolymersBasis of a presentation given at Materials Discussion No. 4, 11â 14 September 2001, Grasmere, UK.
Corvazier, Laurence; Messé, Loic; Salou, Corinne L.O.; Young, Ronald N.; Fairclough, J. Patrick A.; Ryan, Anthony J.; Corvazier Laurence; The Polymer Centre, Department of Chemistry, University of Sheffield; Messé Loic; The Polymer Centre, Department of Chemistry, University of Sheffield; Salou Corinne L.O.; The Polymer Centre, Department of Chemistry, University of Sheffield; Young Ronald N.; The Polymer Centre, Department of Chemistry, University of Sheffield; Fairclough J. Patrick A.; The Polymer Centre, Department of Chemistry, University of Sheffield; Ryan Anthony J.; The Polymer Centre, Department of Chemistry, University of Sheffield
Журнал:
Journal of Materials Chemistry
Дата:
2001
Аннотация:
The orderâ disorder transition (ODT), microdomain structures and the phase diagram for ternary blends of low molecular weight PS, PI and PSâ PI have been determined by a combination of X-ray scattering and transmission electron microscopy. The distribution of the homopolymer within the layers of a related PS/PB/PSâ PB system has also been determined by a combination of X-ray and neutron reflectivity.A series of nearly symmetric, ternary blends of polystyrene (PS), polyisoprene (PI) and polystyrene-block-polyisoprene (PSâ PI) have been studied by small angle X-ray scattering, static light scattering and transmission electron microscopy. The molecular weight of the homopolymers and block copolymer were in the ratio NH/NBCPâ =â 0.19, which gave a block copolymer ODT and a homopolymer blend TC that were similar (TC/TODTâ â â 1.1). The block copolymer and its blends showed a weakly first-order transition from a lamellar phase to a fluctuating disordered phase in the volume fraction range ΦHâ â ¤â 0.77. A bicontinuous microemulsion was found between ΦHâ =â 0.79 and ΦHâ =â 0.93, and for ΦHâ â ¥â 0.93 macrophase separation was observed. In a similar PS, polybutadiene (PB) and polystyrene-block-polybutadiene (PSâ PB) system the distribution of the homopolymer diluent was studied by X-ray and neutron reflectivity with deuterium labelled PS. The initial microstructure formed on spin coating had a dry-brush structure with the homopolymer concentrated in the centre of the domains and on subsequent annealing a wet-brush morphology was observed with the homopolymers uniformly distributed.
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