Figure 4

Influence of surface chemistry on the streaming current for a micro-channeled cantilever with an aperture of 8 µm. (a) Schematic illustration of surface charge in a bare Si₃N₄ cantilever channel at pH 4 and pH 10, respectively. (b) Streaming current as a function of applied pressure for bare Si₃N₄. Solid lines correspond to a linear fit of the experimental data, while dashed lines represent estimations of the streaming current based on literature data^53,54. The shaded areas indicate the possible variations in micro-channel dimensions. (c) Corresponding dI/dp data (filled symbols) at different pH conditions shown for a bare Si₃N₄ channel and literature values (open symbols). (d) Schematic illustration of surface charge in an amino-functionalized channel at pH 4 and pH 10, respectively. (e) Streaming current as a function of applied pressure for an amino-modified channel in comparison to literature data (dashed line)⁵⁷. (f) Corresponding dI/dp data (filled symbols) at different pH conditions shown for an amino-modified channel and literature values (open symbols).