Dewetting of monolayer water and isopropanol between MoS2 nanosheets. Issue 1 (December 2018) - Wang, Beibei
Abstract Understanding dewetting of solvent molecules confined to layered material (LM) interfaces is crucial to the synthesis of two-dimensional materials by liquid-phase exfoliation. Here, we examine dewetting behavior of water and isopropanol/water (IPA/H2 O) mixtures between molybdenum disulfide (MoS2 ) membranes using molecular dynamics (MD) simulations. We find that a monolayer of water spontaneously ruptures into nanodroplets surrounded by dry regions. The average speed of receding dry patches is close to the speed of sound in air. In contrast, monolayer mixtures of IPA/H2 O between MoS2 membranes slowly transform into percolating networks of nanoislands and nanochannels in which water molecules diffuse inside and IPA molecules stay at the periphery of islands and channels. These contrasting behaviors may explain why IPA/H2 O mixtures are much more effective than H2 O alone in weakening interlayer coupling and exfoliating MoS2 into atomically thin sheets.