title: Interfacial pH at an isolated silica-water surface.
abstract: Tethering a pH-sensitive dye to a silica surface enables the interfacial pH to be measured optically and is found to be 2 pH units lower than that of the bulk. The positive H+ ions are attracted by the surface potential and have an enhanced concentration consistent with the previously determined surface potential of order -120 mV, with respect to zero in the bulk. A stable near-surface charged layer once formed is not disrupted by the bulk pH.
authors.affiliation: School of Biological and Chemical Sciences, University of Exeter, Stocker Road, Exeter EX4 4QD, UK.
authors.forename: Josephine P
authors.initials: JP
authors.lastname: O'Reilly
authors.forename: Craig P
authors.initials: CP
authors.lastname: Butts
authors.forename: Ian A
authors.initials: IA
authors.lastname: l'Anson
authors.forename: Andrew M
authors.initials: AM
authors.lastname: Shaw