Multilayer hybrid graphene-polymer coatings for long term corrosion protection

 
Graphene is increasingly being targeted as a constituent of coatings for corrosion resistance. Whilst is is recognised that graphene has excellent barrier properties to gases and liquids, its electrochemical properties as an efficient cathode can lead to micro-galvanic cells and accelerated localised coatings, if defects in the barrier layer exist. To counter this problem, one option is to produce multi-layer coatings, where both conducting graphene and non-conducting polymer layers are applied to the surface. In this respect we report on multi-layered polymer-graphene hybrid coatings with graphene layers being sandwiched between polymer layers, offering effective corrosion protection of a commercial aluminium 2024 alloy in simulated seawater. The corrosion resistance response of these multilayer systems is evaluated through electrochemical impedance spectroscopy and optical/scanning electron microscopy. The magnitude of protection is found to be related to both the number of layers and the specific sequence in which each layer is applied to the surface.