Evidence of glass transition in thin films of maleic anhydride derivatives: Effect of the surfactant coadsorptionD. López-Diaz and M. M. Velázquez
Departamento de Quimica Fisica, Facultad de Ciencias Quimicas, Universidad de Salamanca, E-37008, Salamanca, Spain
Received 24 April 2008 / Published online 7 July 2008
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 100K as compared with those corresponding to the bulk polymers. The coadsorption of the water-insoluble surfactant DODAB decreases the glass transition temperature.PACS
68.15.+e - Liquid thin films.
© EDP Sciences, Società Italiana di Fisica, Springer-Verlag 2008