A poly(ionic liquid)-pillar[5]arene honeycombed isoporous membrane for high performance Cu2+ sensors

Abstract Honeycombed isoporous membranes (HIPMs) represent enabling roles in environment and energy applications, but their preparation by block copolymer self-assembly and transferable breath figure methods involves synthetic complexity and labor intensiveness. Here we report the straightforward preparation of HIPMs through the combinational self-assembly and electrostatic complexation between a poly(ionic liquid) homopolymer and pillar[5]arene molecules. Free-standing HIPMs with defined surface pores and interconnected cross-sectional pores were prepared, embedded with beneficial properties of poly(ionic liquid) and pillar[5]arene supramolecular entities. The polymer synthesis and membrane preparation are facile, and the strategy is applicable to both planar and curved surfaces such as glass plates, particles and fibers. The synergy of surface pores with underlying structures facilitates functionalities beyond separation, such as a HIPMs coating on fiber-optic sensors that feature good responsiveness and limit (0.075 nM) for detecting Cu2+ heavy ions. This work renders the facile preparation of isoporous membranes from ionic liquid homopolymers and their surface coatings for sensors with environmental application potentials.