An interfacial instability in a transient wetting layer leads to lateral phase separation in thin spin-cast polymer-blend films
| Autor: | Richard A. L. Jones, S.Y. Heriot |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
Phase transition
Materials science Rotation Polymers Nanotechnology Complex Mixtures Phase Transition Light scattering Coated Materials Biocompatible Phase (matter) Polymethyl Methacrylate General Materials Science Thin film Composite material Wetting layer chemistry.chemical_classification Mechanical Engineering Membranes Artificial General Chemistry Polymer Condensed Matter Physics Nanostructures chemistry Mechanics of Materials Wettability Polystyrenes Wetting Polymer blend Crystallization |
| Zdroj: | Nature Materials. 4:782-786 |
| ISSN: | 1476-4660 1476-1122 |
| DOI: | 10.1038/nmat1476 |
| Popis: | Spin-coating is a very widely used technique for making uniform thin polymer films. For example, the active layers in most experimental semiconducting polymer-based devices, such as light-emitting diodes and photovoltaics, are made this way. The efficiency of such devices can be improved by using blends of polymers; these phase separate during the spin-coating process, creating the complex morphology that leads to performance improvements. We have used time-resolved small-angle light scattering and light reflectivity during the spin-coating process to study the development of structure directly. Our results provide evidence that a blend of two polymers first undergoes vertical stratification; the interface between the stratified layers then becomes unstable, leading to the final phase-separated thin film. This has given us the basis for establishing a full mechanistic understanding of the development of morphology in thin mixed polymer films, allowing a route to the rational design of processing conditions so as to achieve desirable morphologies by self-assembly. |
| Databáze: | OpenAIRE |
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