A multi-scale and multi-physics model of soft membranes for artificial photosynthesis*

The present work is part of the Sofia project, which envisions the use of soft soap-film based membranes in applications for artificial photosynthesis [1][2]. In particular, we focus on an innovative multiscale and multiphysics model that describes and predicts the performances of a single photosynthetic soap-based membrane for the carbon dioxide (CO₂) conversion into syngas components.

 

We present a macro scale continuum model of the membrane, which includes the transport of species in the soap film [3], and the adsorption/desorption of species and the chemical reactions in the two surfactant monolayers. We further introduced the notion of reactive site in the surfactant monolayers where the CO₂ reduction and water oxidation reactions take place. A Monte Carlo (MC) based mesoscopic model, which investigates the structure of the self-assembled functionalized monolayers, is then developed. The latter model takes as input the molecular characteristics of the surfactants, i.e., their dimension, their charge and their dipole, and generates an ensemble of consistent micro-states of the self-assembled monolayer under given areal concentrations and temperature. The MC model is finally validated against experimental data on surface pressure in Langmuir mono-films.