Effect of spatial confinement on the glass-transition temperature of patterned polymer nanostructures

Manish K. Mundra, Suresh K. Donthu, Vinayak P Dravid*, John M Torkelson

*Corresponding author for this work

Research output: Contribution to journalArticle

62 Scopus citations

Abstract

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 ∼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 (2-0) 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.

Original languageEnglish (US)
Pages (from-to)713-718
Number of pages6
JournalNano letters
Volume7
Issue number3
DOIs
StatePublished - Mar 1 2007

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanical Engineering

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