Produção Nacional
Relaxation times of nanoscale deformations on the surface of a polymer thin film near and below the glass transition
2006; American Physical Society; Volume: 74; Issue: 9 Linguagem: Inglês
10.1103/physrevb.74.094203
ISSN1550-235X
AutoresR.M. Papaléo, R. Leal, Willyan Hasenkamp Carreira, Luiz Gustavo Barbosa, Ismaila Taiwo Bello, Ana Carolina Silva Bulla,
Tópico(s)Ion-surface interactions and analysis
ResumoWe report on measurements of relaxation times of nanometer-sized deformations resulting from the impact of individual energetic ions on poly(methyl methacrylate) surfaces at temperatures close to and below the glass transition ${T}_{g}$. The temporal evolution of the dimensions of the deformations is well described by a stretched exponential function, but with relaxation times $\ensuremath{\tau}(T)$ many orders of magnitude smaller than bulk values at the same $T$. The local ${T}_{g}$ was around $86\phantom{\rule{0.2em}{0ex}}\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$, roughly $30\phantom{\rule{0.2em}{0ex}}\ifmmode^\circ\else\textdegree\fi{}\mathrm{C}$ below the conventional bulk ${T}_{g}$. At the vicinity of the local ${T}_{g}$, $\ensuremath{\tau}(T)$ follows the Vogel-Fulcher type of $T$ dependence, but at lower $T$ a transition towards a less steep behavior is seen.
Referência(s)