Water self-dissociation under the microscope

DAMIAN A SCHERLIS

Seminario; Invited Seminar of the Center for Enhanced Nanofluidic Transport, Massachusetts Institute of Technology, US; 2021

CENT - MIT, USA

Theeffect of extreme confinement on chemical equilibrium is an openquestion whose elucidation poses a major challenge to modernlaboratory techniques. In particular, no experimental information isavailable on the equilibrium constant for water dissociation innanoenvironments, despite speculations suggesting that it may changeby orders of magnitude. In the present talk we show resultsfrom first principles free-energy simulations indicating that the pKwremains unaltered all the way down to subnanometer confinement, whenit is strongly affected by dimensionality and size. All in all, wefind the dependence of pKw with pore size is not a monotonicfunction with a foreseeable trend, but may vary in sharp andunexpected ways in severely confined environments.