INVESTIGADORES
AZZARONI Omar
artículos
Título:
Electrochemical Determination of the Glass Transition Temperature of Thin Polyelectrolyte Brushes at Solid−Liquid Interfaces by Impedance Spectroscopy
Autor/es:
T. ALONSO GARCÍA; M.J. RODRÍGUEZ-PRESA; C. GERVASI; S.E. MOYA; O. AZZARONI
Revista:
ANALYTICAL CHEMISTRY
Editorial:
AMER CHEMICAL SOC
Referencias:
Lugar: Washington; Año: 2013 vol. 85 p. 6561 - 6565
ISSN:
0003-2700
Resumen:
Devising strategies to assess the glass transition temperature (Tg)
of polyelectrolyte assemblies at solid?electrolyte interfaces is very
important to understand and rationalize the temperature-dependent
behavior of polyelectrolyte films in a wide range of settings. Despite
the evolving perception of the importance of measuring Tg
under aqueous conditions in thin film configurations, its
straightforward measurement poses a challenging situation that still
remains elusive in polymer and materials science. Here, we describe a
new method based on electrochemical impedance spectroscopy (EIS) to
estimate the glass transition temperature of planar polyelectrolyte
brushes at solid?liquid interfaces. To measure Tg, the charge transfer resistance (Rct)
of a redox probe diffusing through the polyelectrolyte brush was
measured, and the temperature corresponding to the discontinuous change
in Rct was identified as Tg. Furthermore, we demonstrate that impedance measurements not only facilitate the estimation of Tg
but also enable a reliable evaluation of the transport properties of
the polymeric interface, i.e., determination of diffusion coefficients,
close to the thermal transition. We consider that this approach bridges
the gap between electrochemistry and the traditional tools used in
polymer science and offers new opportunities to characterize the thermal
behavior of complex polymeric interfaces and macromolecular assemblies.