Dynamic diffusion of water inside graphene-reinforced PU/PTFE coatings: A molecular dynamics approach

Abstract

Polymers are extensively used in various applications due to their excellent properties. Recently, graphene-based polymer composites have gotten significant attention due to their superior barrier properties to corrosive media. Although there are lots of experimental studies on graphene-based composites, there are very few works available at the atomistic level using molecular dynamics. The present work investigates the role of temperature on the diffusion of water and the effect of graphene-reinforcement in the polyurethane (PU) and polytetrafluoroethylene (PTFE). The results showed an increase in the diffusion at higher temperatures due to an increase in the mobility of polymeric chains at higher temperatures and hence a smooth path for the travel of water molecules. There is a significant decrease in the diffusion of water molecules in the graphene-reinforced systems when compared with neat PU and PTFE systems. The decrement in the diffusion of water in the range of 273 K to 350 K was around 79–93% for graphene-reinforce PU systems and around 58–62% in the case of graphene-reinforced PTFE systems.