Time Evolution of the Topography of Structured Hybrid Polymer/Nanoparticle Systems

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• 作者：Jenny Kim ; Peter F. Green
• 刊名：Macromolecules
• 出版年：2012
• 出版时间：April 24, 2012
• 年：2012
• 卷：45
• 期：8
• 页码：3496-3502
• 全文大小：396K
• 年卷期：v.45,no.8(April 24, 2012)
• ISSN：1520-5835

文摘

An important class of functional hard/soft hybrid nanocomposites is formed when nanoparticles (NPs) are induced to self-assemble within the structures of ordered A-b-B diblock copolymers (BCPs). Based on their size, NPs will preferentially reside within edge dislocations, defects, which enable the formation of surface structures, islands or holes, in BCP thin films. The islands (and holes), ubiquitous in BCP thin films, coarsen in a manner reminiscent of 2-dimensional phase ordering systems of binary alloys, where the growth is self-similar, governed by classical capillarity driven Ostwald ripening and coalescence mechanisms. In the pure BCP thin films, coarsening initially occurs via coalescence and at later times via Ostwald ripening. In BCP/nanoparticle systems, the dynamics are considerably slower, and throughout similar time scales, the mechanism of coarsening occurs predominantly via coalescence. Contributions to the structural evolution due to Ostwald ripening are comparatively small over these time scales. Our assessments are based on an analysis of the power law growth exponents and of probability density distribution functions of data obtained from samples using microscopy.