Ring-shaped morphology in solution-cast polystyrene-poly(methyl methacrylate) block copolymer thin films
We report observation of ring-shaped morphology formed in thin films of a cylinder-forming polystyrene-b-poly(methyl methacrylate) (PS-b-PMMA) diblock copolymer cast from 1,1,2,2-tetrachloroethane (Tetra-CE) solution via relatively fast solvent evaporation rates, in which Tetra-CE is a good solvent...
| Veröffentlicht in: | Langmuir : the ACS journal of surfaces and colloids. - 1985. - 21(2005), 25 vom: 06. Dez., Seite 11870-7 |
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| Weitere Verfasser: | , , , |
| Format: | Aufsatz |
| Sprache: | English |
| Veröffentlicht: |
2005
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| Zugriff auf das übergeordnete Werk: | Langmuir : the ACS journal of surfaces and colloids |
| Schlagworte: | Journal Article Research Support, Non-U.S. Gov't Polymers Polystyrenes Polymethyl Methacrylate 9011-14-7 |
| Zusammenfassung: | We report observation of ring-shaped morphology formed in thin films of a cylinder-forming polystyrene-b-poly(methyl methacrylate) (PS-b-PMMA) diblock copolymer cast from 1,1,2,2-tetrachloroethane (Tetra-CE) solution via relatively fast solvent evaporation rates, in which Tetra-CE is a good solvent for both blocks but preferential affinity for the minority PMMA block. We studied the microstructure of a set of solution-cast block copolymer films dried with different solvent evaporation rates, R. The control with different R leads to keeping microstructures in different solution concentrations (phi) and bringing mechanical strain fields with different strength in the film, for which faster evaporation rates result in microstructures of lower solution concentrations and mechanical strain fields of higher strength. As R decreases from rapid evaporation (approximately 0.1 mL/h), the film microstructure evolved from an intermediate ringlike morphology sequentially to ring-shaped morphologies including loose and tight rings and then inverted phase of PS spheres in a PMMA matrix and finally reached the equilibrium phase, namely, cylinders of PMMA in a PS matrix. In view of the influence of the film constraints, the microstructure of a film with a terraced free surface profile has been examined. The results indicate that the ring-shaped morphology can form as long as the film thickness is larger than a critical value of about one microdomain spacing. In the case where the film thickness is larger than that value, the nature of solvent and the kinetics of solvent evaporation are shown to be mainly responsible for the ring-shaped morphology formation |
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| Beschreibung: | Date Completed 23.04.2016 Date Revised 03.12.2018 published: Print Citation Status MEDLINE |
| ISSN: | 1520-5827 |