Effect of Spatial Confinement on the Glass-Transition Temperature of Patterned Polymer Nanostructures
| Autor: | Manish K. Mundra, Vinayak P. Dravid, John M. Torkelson, Suresh K. Donthu |
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| Rok vydání: | 2007 |
| Předmět: |
chemistry.chemical_classification
Nanostructure Materials science Silicon Mechanical Engineering Transition temperature chemistry.chemical_element Bioengineering General Chemistry Polymer Condensed Matter Physics Triglycine sulfate chemistry.chemical_compound chemistry Chemical engineering Polymer chemistry General Materials Science Thin film Glass transition Electron-beam lithography |
| Zdroj: | Nano Letters. 7:713-718 |
| ISSN: | 1530-6992 1530-6984 |
| Popis: | Poly(methyl methacrylate) (PMMA) nanostructures embedded with a fluorescence tag are fabricated using electron beam lithography on oxidized silicon substrates. The glass transition temperatures (Tgs) of these one-dimensional (1-D) nanostructures (parallel lines) are measured by monitoring their temperature-dependent fluorescence intensities, revealing substantial differences between the Tgs of the nanostructures and the thin films from which they were fabricated. For example, the Tg of 50-nm-wide PMMA nanolines on silica is approximately 15 K lower than that of a PMMA film on silica of the same 18 nm thickness. Attractive PMMA-silica interfacial interactions increase the Tg, while free surfaces decrease the Tg of PMMA in ultrathin films relative to bulk PMMA. Thus, the significant differences between the Tgs of the 1-D and two-dimensional (2-D) forms of PMMA on silica are the result of a substantial increase in the ratio of free-surface area to interfacial area in the PMMA nanolines relative to ultrathin films. |
| Databáze: | OpenAIRE |
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