First- and second-order phase transitions in the adlayer of biadipate on Au(111).
The adsorption of biadipate on Au(111) was studied by cyclic voltammetry and chronocoulometry. The biadipate adlayer undergoes a potential-driven phase transition. It is shown that the phase transition can be either of the first- or second-order depending on the biadipate concentration. At low surfactant concentrations, the first-order transition is characterised by a discontinuity in the charge density-potential curve and by the presence of very sharp peaks in the voltammetric response. At higher concentrations, these peaks are no longer observed but a discontinuity in the capacity curve is still noticeable, in agreement with a second-order transition.
Doneux
Th
T
Chimie Analytique et Chimie des Interfaces, Faculté des Sciences, Université Libre de Bruxelles, Boulevard du Triomphe, 2, CP 255, B-1050 Bruxelles, Belgium. tdoneux@ulb.ac.be
Nichols
R J
RJ