Physical Sciences and Mathematics Commons^™

Electrostatic Deposition Of Polycations And Polyanions Onto Cysteine Monolayers, Mark Anderson

Mark R. Anderson

Electrochemical impedance spectroscopy and the quartz crystal microbalance are used to monitor the deposition of polyelectrolytes onto an interface modified with a monolayerofcysteine. When using an anionic redox probe, Fe(CN)−46, the impedance of the cysteine modified electrode is a function of the solution pH; the charge-transfer resistance being higher at basic pH, and smaller under acidic conditions relative to the value found when the solution is buffered near the pI for cysteine. This behavior is consistent with the electrostatic interaction between the anionic redox probe and the net charge of the interface. After exposure of the cysteine-modified interface to 0.10 …