Probing liquid vertical bar liquid interfaces using neutron reflection measurements and scanning electrochemical microscopy

A new experimental approach to neutron reflectivity experiments at liquid \ liquid interfaces is presented. This approach allows the investigation of the interface between two immiscible electrolyte solutions. The experimenta l design involves establishing a thin (sub-10 mu m) aqueous layer on a sing le crystal quartz block which is then positioned over a PTFE trough contain ing the organic phase. The dimensions of the thin aqueous film, necessary f or the neutron studies, have been characterised using scanning electrochemi cal microscopy (SECM) double potential step chronoamperometry measurements. Initial results of neutron reflection at the 1,2-dichloroethane \ aqueous potassium hydroxide interface show a smooth interface with a root mean squa re roughness less than 10 Angstrom, in agreement with theoretical predictio ns. (C) 2000 Elsevier Science S.A. All rights reserved.