INQUIMAE   12526
INSTITUTO DE QUIMICA, FISICA DE LOS MATERIALES, MEDIOAMBIENTE Y ENERGIA
Unidad Ejecutora - UE
artículos
Título:
Molecular Modeling of Responsive Polymer Films
Autor/es:
MARIO TAGLIAZUCCHI; ERNESTO J. CALVO; IGAL SZLEIFER
Revista:
AICHE JOURNAL
Editorial:
JOHN WILEY & SONS INC
Referencias:
Año: 2010 vol. 56 p. 1952 - 1959
ISSN:
0001-1541
Resumen:
In this perspective, we have shown three different cases of
responsive polymers at surfaces where the properties of the
surface can be varied in response to cues from the bulk solution
or in the presence of an external field. The most important
conclusion in all three cases is that the chemical reaction equilibrium,
physical interactions and molecular organization are
strongly coupled, and it is imperative to consider the global
and local changes that occur to the surface structure and properties
due to this coupling. In particular acid-base and redox
equilibrium are very different in polymer-modified surfaces
than in the corresponding bulk solutions. Moreover, the definition
of apparent redox potentials and apparent pKa
results from the averaging over highly inhomogeneous values,
and, therefore, they do not necessarily represent the state of
the layer and the local values and their variation are very
important for the design of functional surfaces. The very large
variation on chemical equilibrium results from the optimization
of all the interactions. The picture that emerges is that trying
to deduce what the final state of the system is by looking
at the individual optimization of each contribution leads to
qualitative incorrect assumptions and only the minimization
of the complete free energy leads to the proper behavior in
these complex systems.a
results from the averaging over highly inhomogeneous values,
and, therefore, they do not necessarily represent the state of
the layer and the local values and their variation are very
important for the design of functional surfaces. The very large
variation on chemical equilibrium results from the optimization
of all the interactions. The picture that emerges is that trying
to deduce what the final state of the system is by looking
at the individual optimization of each contribution leads to
qualitative incorrect assumptions and only the minimization
of the complete free energy leads to the proper behavior in
these complex systems.