title: Controlling swelling/deswelling of stimuli-responsive hydrogel nanofilms in electric fields.
abstract: The swelling/deswelling transition of pH-sensitive, electrode-grafted, hydrogel nanofilms when exposed to electric fields is studied by theoretical analysis. In acidic conditions, the response of these films to changes in pH is dominated by network-surface interactions, while intra-network electrostatic repulsions, which are highly modulated by the adsorption of salt ions, determine material response at a higher pH. Film thickness is a non-monotonic function of solution pH and displays a local maximum, a local minimum or both, depending on the salt concentration and the applied voltage. We suggest the use of these materials in the development of biosensors and control of enzyme activity.
authors.affiliation: Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), CONICET, La Plata, Argentina. longogs@inifta.unlp.edu.ar.
authors.forename: Gabriel S
authors.initials: GS
authors.lastname: Longo
authors.affiliation: Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois, USA and Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois, USA.
authors.forename: Monica
authors.initials: M
authors.lastname: Olvera de la Cruz
authors.affiliation: Chemistry of Life Processes Institute, Northwestern University, Evanston, Illinois, USA and Department of Biomedical Engineering, Northwestern University, Evanston, Illinois, USA and Department of Chemistry, Northwestern University, Evanston, Illinois, USA.
authors.forename: Igal
authors.initials: I
authors.lastname: Szleifer