Figure 4.

Impedance QCM measurement results of the formation of a polyelectrolyte multilayer (PEM) on top of a silicon dioxide coated quartz crystal (5 MHz resonance frequency). (a) Experimental data showing the stepwise decrease in resonance frequency (left axis, third harmonic, not normalized) and resistance (right axis) due to the sequential injection of solutions of poly(allylammonium hydrochloride) (PAH, 1 mM) and poly(sodium styrene sulfonate) (PSS, 1 mM) in the presence of NaCl (0.5 M). A 10 point moving average filter was applied to the raw data. The polymer was injected for 10 min at a flow rate of 50 µL/min followed by a 5 min injection of 0.5 M NaCl solution; and (b) calculated mass uptake (left axis) per electrode area and dissipation values (right axis) for the individual polymer layers.