Glass transition in ultrathin polymer films: a thermal expansion study.
Phys Rev E Stat Nonlin Soft Matter Phys
; 71(4 Pt 1): 041801, 2005 Apr.
Article
em En
| MEDLINE
| ID: mdl-15903691
ABSTRACT
The glass transition process gets affected in ultrathin films having thickness comparable to the size of the molecules. We observe systematic broadening of the glass transition temperature (T(g)) as the thickness of an ultrathin polymer film reduces below the radius of gyration but the change in the average T(g) was found to be very small. The existence of reversible negative and positive thermal expansion below and above T(g) increased the sensitivity of our thickness measurements performed using energy-dispersive x-ray reflectivity. A simple model of the T(g) variation as a function of depth expected from sliding motion could explain the results.
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01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Phys Rev E Stat Nonlin Soft Matter Phys
Assunto da revista:
BIOFISICA
/
FISIOLOGIA
Ano de publicação:
2005
Tipo de documento:
Article
País de afiliação:
Índia