Thickness induced structural changes in polystyrene films

Changes to the structure of polystyrene melt films as measured through the spectrum of density fluctuations have been observed as a function of film thickness down to the polymer radius of gyration (Rg). Films thicker than 4Rg show bulklike density fluctuations. Thinner films exhibit a peak in S(q)...

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Bibliographic Details
Published inPhysical review letters Vol. 101; no. 11; p. 115501
Main Authors Mukhopadhyay, M K, Jiao, X, Lurio, L B, Jiang, Z, Stark, J, Sprung, M, Narayanan, S, Sandy, A R, Sinha, S K
Format Journal Article
LanguageEnglish
Published United States 12.09.2008
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Summary:Changes to the structure of polystyrene melt films as measured through the spectrum of density fluctuations have been observed as a function of film thickness down to the polymer radius of gyration (Rg). Films thicker than 4Rg show bulklike density fluctuations. Thinner films exhibit a peak in S(q) near q=0 which grows with decreasing thickness. This peak is attributed to a decreased interpenetration of chains resulting in an enhanced compressibility. Measurements were made using small angle x-ray scattering in a standing wave geometry designed to enhance scattering from the interior of the film compared to interface scattering.
ISSN:0031-9007
DOI:10.1103/PhysRevLett.101.115501