posted on 2022-03-15, 17:04authored byVincent Senechal, Juan Rodriguez-Hernandez, Carlos Drummond
We explored the effect of an applied
electric field on the molecular
conformation of two weak polyelectrolytes grafted on gold electrodespoly(acrylic
acid) and the weak polybase poly(2-(dimethylamino)ethyl methacrylate)by
combining a quartz crystal microbalance with an electrochemical setup.
Our results indicate that different mechanisms influence the response
of weak polyelectrolytes to an externally applied potential difference,
including electrochemical modification of the local pH by oxygen reduction
and the electrostatic interaction between the metallic electrode and
the charged monomers and ions in solution. Our results evidence that
fine control of polymer conformation can be readily obtained at low
applied potentials, opening pathways for precise, localized control
of surface properties. However, these applications require considering
the history-dependent behavior of polyelectrolyte brushes, hysteresis
in the response, and the influence of electrochemical reactions driven
by potential changes.