The Role of Interlayer Spacing in Fluid Permeability of Barrier Materials with 2D Inclusions

A wealth of results over the last decade has demonstrated the virtues of incorporating 2D materials, including and especially graphene oxide (GO), to reduce fluid permeability in composite barrier materials. Motivated by several exciting but seemingly inconsistent results in the literature on such barrier materials, in this talk, we highlight the importance of a previously underappreciated factor that can play a surprisingly large role in fluid permeability, namely, the interlayer spacing of the 2D inclusions (which can be affected by fluid initially imbibed within the material as well as flexibility and surface functionalization of the 2D materials, amongst other factors). In support of our claims, we have performed molecular-dynamics (MD) simulations that study the influence of interlayer spacing on fluid permeability across a range of systems with varying geometries and driving forces. Based upon our MD results, we construct a non-equilibrium phase map that identifies conditions corresponding to effective barrier behavior.