Glass Transition Dynamics and Surface Layer Mobility in Unentangled Polystyrene Films
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- Zhaohui Yang
- Department of Physics, Boston University, Boston, MA 02215, USA.
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- Yoshihisa Fujii
- Department of Physics, Boston University, Boston, MA 02215, USA.
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- Fuk Kay Lee
- Department of Physics, Boston University, Boston, MA 02215, USA.
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- Chi-Hang Lam
- Department of Applied Physics, Hong Kong Polytechnic University, Hong Kong.
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- Ophelia K. C. Tsui
- Department of Physics, Boston University, Boston, MA 02215, USA.
説明
<jats:title>Tangle-Free Polymer Dynamics</jats:title> <jats:p> The dynamics of polymer chains at interfaces will differ from the dynamics in the bulk. While hard interfaces generally cause chain motions to slow down, at free surfaces the dynamics should generally speed up. A consequence is that for thin polymer films, there should be a reduction in the glass transition temperature ( <jats:italic>T</jats:italic> <jats:sub>g</jats:sub> ), but a wide range of effects have been seen in different polymeric materials. Now, <jats:bold> Yang <jats:italic>et al.</jats:italic> </jats:bold> (p. <jats:related-article xmlns:xlink="http://www.w3.org/1999/xlink" ext-link-type="doi" page="1676" related-article-type="in-this-issue" vol="328" xlink:href="10.1126/science.1184394">1676</jats:related-article> ) show that for short, unentangled polystyrene polymers, there is a direct correlation between the viscosity and the glass transition temperature, and that the reduction in <jats:italic>T</jats:italic> <jats:sub>g</jats:sub> is due to a surface mobile layer that dominates the behavior as the films decrease in thickness. </jats:p>
収録刊行物
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- Science
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Science 328 (5986), 1676-1679, 2010-06-25
American Association for the Advancement of Science (AAAS)