Atomic modelling of crystal/complex fluid/crystal contacts—Part II. Simulating AFM tests via the GenMol code for investigating the impact of CO2 storage on kaolinite/brine/kaolinite adhesion

GenMolTM code is used to simulate Atomic Force Microscopy (AFM) tests at a kaolinite/brine/kaolinite contact, the confined fluid in sub-nanometre interspaces being in equilibrium with an external multi-species solution. The attraction/repulsion effort, i.e. the derivative versus the interspace aperture h of the interaction energy between both kaolinite faces, is computed versus the variable composition of the confined fluid (see for the method Part I of this work). Two external solutions are tested. Solution S1 is a neutral brine (pH=7.5) leading to a possible attraction for apertures lower than 7 Å. Solution S2 is an acidified brine (pH=3.2) leading to repulsion whatever may be the aperture h. These two AFM simulations prove the existence of a critical pH value (3.2