Dynamics in polydimethylsiloxane. The effect of solute polarity
- Stanford Univ., CA (United States)
The temperature dependent dynamics of polydimethylsiloxane (PDMS) melts are investigated by measuring orientational relaxation of a dissolved probe molecule, 2-naphthyltriethoxysilane (NTES) using time resolved fluorescence depolarization. The temperature dependent viscosity of PDMS is also reported for two molecular weights. The measurements of nonpolar NTES probe dynamics are compared to previous measurements on the polar probe, N-(triethoxysilylpropyl)dansylamide. The activation energies for the orientational relaxation of the two probes are very different. This is discussed in terms of the influence of the polarity of the solutes on the local structure in the melts. The results have implications for possible modifications of the physical properties of PDMS materials by using solutes or side groups of varying polarity. The synthesis of the NTES probe, which can also be used as a cross-linking reagent for PDMS, is also described. 38 refs., 4 figs., 1 tab.
- DOE Contract Number:
- FG03-84ER13251
- OSTI ID:
- 5041698
- Journal Information:
- Journal of the American Chemical Society; (United States), Journal Name: Journal of the American Chemical Society; (United States) Vol. 116:3; ISSN JACSAT; ISSN 0002-7863
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
400102 -- Chemical & Spectral Procedures
400201* -- Chemical & Physicochemical Properties
400500 -- Photochemistry
ALKALINE EARTH METAL COMPOUNDS
ANISOTROPY
AROMATICS
FLUORESCENCE
GRIGNARD REAGENTS
LUMINESCENCE
MAGNESIUM COMPOUNDS
MAGNETIC RESONANCE
MELTING
MOLECULAR WEIGHT
NUCLEAR MAGNETIC RESONANCE
ORGANIC COMPOUNDS
ORGANIC SILICON COMPOUNDS
ORGANOMETALLIC COMPOUNDS
PHASE TRANSFORMATIONS
POLYMERS
PROBES
RESONANCE
SILICONES
SILOXANES
TEMPERATURE DEPENDENCE
VISCOSITY