Photo- and Thermosensitive Polymer Membrane with a Tunable Microstructure Doped with Graphene Oxide Nanosheets and Poly(N-isopropylacrylamide) for the Application of Light-Cleaning

Abstract

Traditional polymer membranes exhibit a constant structure that makes adjustment of the filtration process difficult, such as flux changing and contaminant cleaning. Inspired by the automatically closing behavior of leaf stomata under strong light, we prepared a membrane with thermo- and photosensitivities, whose microstructure, as well as filtration properties, could be controlled by adjusting the light condition. The membrane was fabricated by the immersion phase inversion method with a casting solution of polyvinylidene fluoride-g-poly­(N-isopropylacrylamide) (PVDF-g-PNIPAAm) and graphene oxide (GO) nanosheets. Additionally, the membrane could be heated to a high temperature in a short time under illumination, causing shrinkage of its PNIPAAm chains and expansion of its membrane pores. On the basis of the reversible photoinduced structural transformation, the membrane exhibited a high water gating ratio under the switching of light on/off. Moreover, we proposed a novel and simple method to clear the contaminant from the pores of the membrane via light, which we named “light-cleaning”. Light-cleaning had a flux recovery rate of 99.2%, substantially higher than that of back-washing (62%). This work not only extends the controllability and functionality of the polymer membrane but also develops a new membrane cleaning system.

Preparation and characterisation of graphene oxide containing block copolymer worm gels

“…It is likely that this route is not specific to GO as a re-enforcing nanomaterial and it is expected that this novel class of composite gel has potential applications in many areas of materials science. [81][82][83]…”

Microscopically tuning the graphene oxide framework for membrane separations: a review

“…Another study of thermal-responsive GO–polymer composite membranes was performed using polyvinylidene fluoride- graft -poly( N -isopropylacrylamide) as the matrix. 47 The thermally responsive nature of poly( N -isopropylacrylamide) allowed the tunability of pore size and water permeance at different temperatures. Recently, bio-inspired strategies are applied to design and fabricate GOMs with ordered nanostructures and enhanced permeability and stability.…”

NIR Activated Upper Critical Solution Temperature Polymeric Micelles for Trimodal Combinational Cancer Therapy

“…Among different drug delivery systems, , thermosensitive polymers show particular potential for controlled drug release due to great potential for spatiotemporally controlled drug release. , Thermosensitive polymers can mainly be divided into two categories, one displaying a lower critical solution temperature (LCST), the other showing upper critical solution temperature (UCST) . LCST polymers are soluble below the critical temperature and insoluble above the critical temperature, whereas UCST polymers show the opposite phenomenon .…”