Anomalous thickness dependence of nano-composite layer-by-layer membranes

Homogenous, impermeable platelet dispersions significantly enhance the barrier properties of polymer composite membranes. Layer-by-layer (LbL) deposition allows achieving the highest degree of orientation in comparison to melt blending or solution casting. However, membranes produced by assisted self-assembly, exhibit a strong thickness dependence of their barrier properties. Such behavior could arise from an unevenly dispersed phase distribution in the continuous phase. Here, we analyze this anomalous thickness dependence of gas permeability in platelet–polymer composites produced by the LbL method and on the basis of this result we present a design criterion for these systems.