Engineering

Oxide

Biofouling

Materials science

Graphene

Fouling

Biochemistry

Chemical engineering

Polymer

Nanotechnology

Organic chemistry

Membrane

Amphiphile

Hydrophobic effect

Copolymer

Permeance

Composite material

Chemistry

Surface energy

Permeation

Nature Communications

Engineering surface chemistry to precisely control interfacial interactions is crucial for fabricating superior antifouling coatings and separation membranes. Here, we present a hydrophobic chain engineering strategy to regulate membrane surface at a molecular scale. Hydrophilic phytic acid and hydrophobic perfluorocarboxylic acids are sequentially assembled on a graphene oxide membrane to form an amphiphilic surface. The surface energy is reduced by the introduction of the perfluoroalkyl chains while the surface hydration can be tuned by changing the hydrophobic chain length, thus synergistically optimizing both fouling-resistance and fouling-release properties. It is found that the surface hydration capacity changes nonlinearly as the perfluoroalkyl chain length increases from C4 to C10, reaching the highest at C6 as a result of the more uniform water orientation as demonstrated by molecular dynamics simulations. The as-prepared membrane exhibits superior antifouling efficacy (flux decline ratio <10%, flux recovery ratio ~100%) even at high permeance (~620 L m-2 h-1 bar-1) for oil-water separation.

Antifouling graphene oxide membranes for oil-water separation via hydrophobic chain engineering