pH-dependent wettability of carboxyphenyl films grafted
to glassy carbon
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- Abell, Andrew David Brooksby, Paula A. Downard, Alison J. Packwood, Daniel M.
- Surfaces than can switch their properties in
response to external stimuli are of fundamental as well as
technological interest. A prerequisite for successful switching in
thin surface layers is sufficient free volume in the layer to allow
molecular motions or reactions. Multilayer films grafted from
aryldiazonium salts have a loosely packed structure and are good
candidates for preparation of switchable surfaces. In this work,
the pH-dependent wettability of carboxyphenyl films on glassy
carbon surfaces is examined using water contact angle measurements.
The film structure is manipulated by exposing freshly grafted films
to solvents of different polarity; this influences the wettability
differences observed between low- and high-pH measurements. The
order of measurement of contact angles (from low pH to high, or
vice versa) also influences the pH-dependent wettability. The
results are consistent with film reorganization, including the
formation of dimeric hydrogen-bonded structures, in response to the
polarity and pH of the surrounding medium.
- Daniel M. Packwood, Paula A. Brooksby, Andrew D.
Abell and Alison J. Downard
- CSIRO Publishing
- Journal article
- Copyright CSIRO 2011
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