Structural relaxation of nanoconfined glassy polymer systems studied by fluorescence measurements

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

Polymers confined to nanoscopic geometries have shown a substantial deviation in the glass transition temperature (Tg) relative to that of the bulk material. How these deviations in Tg alter the structural relaxation of polymeric glasses confined to nanoscopic geometries has emerged as a key question that needs to be addressed for both scientific and technological reasons. Here the effect of nanoconfinment, surfaces, and interfaces on structural relaxation of glassy polymers is investigated by a fluorescence method. Rotor dyes are used as probes (< 0.2wt%) dispersed in the polymer or as labels covalently attached (< 1 label/400 repeat units) to the polymer. Fluorescence intensity increases as local specific free volume / local mobility surrounding the dye decreases, exhibiting a nearly linear change with logarithmic aging time. For ultrathin PMMA films, which have attractive polymer-substrate interactions, a reduction in physical aging rate is observed compared to the bulk. For ultrathin PS films, which lack polymer-substrate interactions, the physical aging rate is nearly identical to that of the bulk. Using a multi-layer method we are able to determine a distribution of physical aging rates across supported PMMA films; relative to bulk there is a reduction in physical aging rate at the free-surface and an even greater reduction in physical aging rate at the substrate.

Original languageEnglish (US)
Title of host publication05AIChE
Subtitle of host publication2005 AIChE Annual Meeting and Fall Showcase, Conference Proceedings
Number of pages1
StatePublished - Dec 1 2005
Event05AIChE: 2005 AIChE Annual Meeting and Fall Showcase - Cincinnati, OH, United States
Duration: Oct 30 2005Nov 4 2005

Other

Other05AIChE: 2005 AIChE Annual Meeting and Fall Showcase
CountryUnited States
CityCincinnati, OH
Period10/30/0511/4/05

Fingerprint

Structural relaxation
Aging of materials
Fluorescence
Polymers
Ultrathin films
Labels
Polymeric glass
Substrates
Dyes
Geometry
Free volume
Rotors

ASJC Scopus subject areas

  • Engineering(all)

Cite this

Priestley, R. D., Broadbelt, L. J., & Torkelson, J. M. (2005). Structural relaxation of nanoconfined glassy polymer systems studied by fluorescence measurements. In 05AIChE: 2005 AIChE Annual Meeting and Fall Showcase, Conference Proceedings
Priestley, Rodney D. ; Broadbelt, Linda J. ; Torkelson, John M. / Structural relaxation of nanoconfined glassy polymer systems studied by fluorescence measurements. 05AIChE: 2005 AIChE Annual Meeting and Fall Showcase, Conference Proceedings. 2005.
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Priestley, RD, Broadbelt, LJ & Torkelson, JM 2005, Structural relaxation of nanoconfined glassy polymer systems studied by fluorescence measurements. in 05AIChE: 2005 AIChE Annual Meeting and Fall Showcase, Conference Proceedings. 05AIChE: 2005 AIChE Annual Meeting and Fall Showcase, Cincinnati, OH, United States, 10/30/05.

Structural relaxation of nanoconfined glassy polymer systems studied by fluorescence measurements. / Priestley, Rodney D.; Broadbelt, Linda J.; Torkelson, John M.

05AIChE: 2005 AIChE Annual Meeting and Fall Showcase, Conference Proceedings. 2005.

Research output: Chapter in Book/Report/Conference proceedingConference contribution

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Priestley RD, Broadbelt LJ, Torkelson JM. Structural relaxation of nanoconfined glassy polymer systems studied by fluorescence measurements. In 05AIChE: 2005 AIChE Annual Meeting and Fall Showcase, Conference Proceedings. 2005