Figure 1.

AFM topographical images in air of TBA molecules, immobilized onto HOPG by spontaneous adsorption during 3 minutes, from solutions of 1 μg mL⁻¹ TBA in pH 7.0 0.1 M phosphate buffer: (a, b) in the absence and (c, d) in the presence of 100 mM K⁺, after (c) 1 hour and (d) 24 hours of incubation.