Photo-switchable membranes constructed from graphene oxide/star-PDMS nanocomposites for gas permeation control

Abstract

A novel, photo-responsive membrane based on a star-shaped polydimethylsiloxane (PDMS) polymer and graphene-based nanosheets was for the first time designed and fabricated for controlling gas permeation. The sub-60 nm thick membrane exhibited continuous photo-reversible gas permeance control when irradiated with UV light of variable wavelengths. By optimising the nanosheet loading and nanosheet–polymer interface, the defect-free membrane demonstrated a satisfactory gas separation performance towards CO₂ and C₃H₈, allowing the membrane to potentially be useful as a photoresponsive coating for applications such in modern plant cultivation technologies. The effect of the nanosheets on the photo-triggering mechanism, a [2 + 2] cycloaddition reaction, was investigated, which revealed that the presence of the nanosheets improved the polymerisation reaction, but hindered the de-polymerisation reaction. Overall, this work provides a new opportunity for the production and investigation of a new class of photo-responsive two-dimensional nanocomposite membranes for highly controlled molecular/ion sieving.