Glass transitions of thin polymeric films: speed and load dependence in lateral force microscopy
Anno: 2000
Autori: Dinelli F., Buenviaje C., Overney R.M.
Affiliazione autori: University of Washington, Department of Chemical Engineering, Benson Hall, Box 351750, Seattle, Washington 98195 (USA)
Abstract: The glass transition of thin polymeric films can be profitably studied using lateral force microscopy (LFM) if the system is calibrated regarding operational parameters, in particular the applied load and the scanning velocity. We have established that these two parameters significantly influence the occurrence of an apparent glass transition. In particular, we have found that the local pressure, applied by the LFM tip, is insufficient to generate a hydrostatic pressure effect causing an increase in the apparent transition temperature. In fact, at a constant scan velocity and for increased load, the apparent transition temperature decreases towards the actual bulk value. Further discussions in this article are based on viscoelastic theories. Critical time scales that are characteristic for sliding are compared to polymer relaxation times, and provide an estimate of the viscosity temperature dependence.
Giornale/Rivista: JOURNAL OF CHEMICAL PHYSICS
Volume: 113 (5) Da Pagina: 2043 A: 2048
Parole chiavi: Thin polymeric films; Lateral force microscopy (LFM), Viscoelasticity; Hydrostatics; Glass transitions
DOI: 10.1063/1.482012Citazioni: 50dati da “WEB OF SCIENCE” (of Thomson Reuters) aggiornati al: 2024-05-12Riferimenti tratti da Isi Web of Knowledge: (solo abbonati) Link per visualizzare la scheda su IsiWeb: Clicca quiLink per visualizzare la citazioni su IsiWeb: Clicca qui