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Updated: Jun 14, 2026

Molecular Entanglement and Electrospinnability of Biopolymers
Published on: September 3, 2014
Reduced viscosity of the free surface in entangled polymer melt films
Tadanori Koga1, C Li, M K Endoh
1Chemical and Molecular Engineering Program, Department of Materials Science and Engineering, Stony Brook University, Stony Brook, New York 11794-2275, USA. tkoga@notes.cc.sunysb.edu
Abstract:
By embedding "dilute" gold nanoparticles in single polystyrene thin films as "markers", we probe the local viscosity of the free surface at temperatures far above the glass transition temperature (T(g)). The technique used was x-ray photon correlation spectroscopy with resonance-enhanced x-ray scattering. The results clearly showed the surface viscosity is about 30% lower than the rest of the film. We found that this reduction is strongly associated with chain entanglements at the free surface rather than the reduction in T(g).
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