Proton hopping/diffusion at solid-liquid interfaces is known to affect surface conductivity. Yet, the broader influence of surface reactions and their kinetics on the thermodynamic and transport properties in the electrical double layer are usually ignored as physical models consider static surfaces. Such simplifying assumptions with regard to electrical double layer properties can have enormous consequences for electrokinetic transport, colloidal stability, or the performance of electrochemical devices.<br/><br/>My coworkers and I have developed a novel molecular dynamics method to effectively mimic reactions of surface functional groups for an oxide in contact with an electrolyte solution. This method allows the surface charge distribution to evolve in time at no additional computational cost compared to a conventional non-reactive molecular dynamics simulation. We have applied our method to an amorphous silica slit pore in which we accounted for the protolysis events on the silanol groups.<br/><br/>In my talk, I will show that the rate of surface reactions greatly influences counterion adsorption, which in turn affects the zeta-potential and electroosmotic flow. I will show that the reaction rate can even flip the sign of the zeta potential and the direction of electroosmotic flow.

How surface reactions and their kinetics impact the electrical double layer structure and dynamics

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