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) 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.
Mukhopadhyay
M K
MK
Department of Physics, University of California San Diego, La Jolla, California 92093, USA.
Jiao
X
X
Lurio
L B
LB
Jiang
Z
Z
Stark
J
J
Sprung
M
M
Narayanan
S
S
Sandy
A R
AR
Sinha
S K
SK