Evidence of glass transition in thin films of maleic anhydride derivatives: effect of the surfactant coadsorption.
The glass transition temperature of poly (maleic anhydride-alt-1-octadecen) and poly (styrene-co-maleic anhydride) cumene-terminated thin films has been measured by mechanical relaxation of Langmuir films of these polymers. The dynamical properties show glass-like features (non-Arrhenius relaxation times and non-Debye mechanical response) interpreted by the coupling model. The glass transition temperature values determined by a mechanical relaxation experiment (step-compression) agree very well with those obtained by surface potential measurements. It is found that the glass transition temperature values in thin films decrease by about 100 K as compared with those corresponding to the bulk polymers. The coadsorption of the water-insoluble surfactant DODAB decreases the glass transition temperature.
López-Díaz
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Departamento de Química Física, Facultad de Ciencias Químicas, Universidad de Salamanca, E-37008-Salamanca, Spain.
Velázqueza
M M
MM