This is one of a pair of linked proposals, one for SURF and one for INTER. The voltage response of poly(2-dimethylaminoethyl methacrylate) (PDMAEMA) weak polybase brushes exhibits two distinct timescales ¿ a fast ¿switching¿ while the voltage is applied followed by a slow recovery. The advent of the INTER reflectometer opens up the possibility of measuring on the length and time scales necessary to resolve changes in the structure of the brush as they happen. Since INTER is so new we are flexible in our expectations but the aim is to gain a detailed time-resolved structure of the brush on application of positive and negative voltages of magnitude 5-10 V in solutions of varying monovalent salt concentrations. PDMAEMA brushes will be grafted from 5 cm silicon blocks and held in a custom liquid cell with built in electrodes, and voltages will be applied using an automated voltage supply.