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Publication Citation: A Broad Perspective on the Dynamics of Highly Confined Polymer Films

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Author(s): Christopher L. Soles; Jack F. Douglas; Wen-Li Wu; H Peng; D W. Gidley;
Title: A Broad Perspective on the Dynamics of Highly Confined Polymer Films
Published: January 01, 2002
Abstract: The manner in which the dynamics of a polymer are affected by thin film confinement is of technological significance, impacting thin film applications such as lubricants, adhesives, and chemically amplified photoresists. In this manuscript we use specular X-ray reflectivity (SXR), beam positron annihilation lifetime spectroscopy (PALS), and incoherent neutron scattering (INS) to study the influence of thin film confinement on the apparent glass transition temperature Tg and the thermal expansion coefficients of thin polycarbonate (PC) films. Both the SXR and PALS indicate a significant suppression of Tg when the film thickness becomes less than 200 . However, the INS measurements suggest an increase in the apparent Tg below this same length scale. These disparate estimates of the thin film Tg seem to indicate that each technique is sensitive to slightly different aspects of the glass formation process. However, all three agree that thin film confinement results in reduced thermal motion, regardless of the precise temperature that is 'designated' as the thin film Tg.
Citation: MRS Conference
Volume: 265(2)
Keywords: dynamics,glasstransition,neutron scattering,positron annihilation,thin films,x-ray reflectivity
Research Areas:
PDF version: PDF Document Click here to retrieve PDF version of paper (98KB)