Functional Elastomeric Copolymer Membranes Designed by Nanoarchitectonics Approach for Methylene Blue Removal

Abstract

The nanoarchitectonic approach, based on nanoscale structural units combination for achieving materials with predesignated properties, was used for assembling elastomeric membranes with specific adsorption abilities. A triblock copolymer polystyrene-b-poly(ethylene-ran-butylene)-b-polystyrene-graft-maleic anhydride (PSEBMA), containing 2 wt% of maleic anhydride moieties, was selected for conferring both elastomeric properties and covalent reticulation/functionalization points to the materials. Covalently crosslinked membranes were obtained by condensation of maleic anhydride units with bisamine linkers, leading to amide and imide bonds formation. Tuning the molecular weight (1kDa or 8kDa) and the stoichiometric ratio of bisamine linkers enabled controlling the mechanical properties of elastomeric membranes, reaching a toughness of 1.35 MJ m−3 with a fracture strain exceeding 100%. Functionalization of these membranes was achieved by covalent reaction with β-aminocyclodextrins (CD), enabling cumulating elastomeric properties with host–guest complexation abilities. CD-functionalized PSEBMA membranes were tested for removal of methylene blue (MB) as a model aromatic pollutant, demonstrating specific adsorption abilities up to 18 mg g−1 of grafted CD. These findings were supported by physical–chemical investigations using ATR–FTIR, UV–Vis, TGA, and BET sorption, as well as morphological investigations through SEM, and mechanical analysis by strain-to-break measurements.