High free volume polymers for pervaporation

This paper provides a review of the latest developments in the design and study of pervaporation membranes based on glassy polymers with a high free volume. Such membranes demonstrate competitive results compared to other membranes described in the literature (rubbery polymers and zeolites) for the separation of alcohols and other volatile organic compounds from aqueous solutions, as well as for the separation of organic/organic mixtures such as methanol/ethylene glycol and dimethyl carbonate/methanol. Incorporation of fillers such as porous aromatic framework, hypercrosslinked polystyrenes and functionalized graphene-like fillers into glassy polymers with internal microporosity to form mixed matrix membranes can improve separation efficiency and reduce membrane aging effects. There is a wide range of materials that have yet to be explored for possible use in pervaporation, which have the potential to create customized membranes for a wide range of aqueous separations. Inexpensive and highly scalable polymers are still the dominant membrane materials for pervaporation. Stabilizing the membrane structure with minimal performance degradation associated with reducing the thickness of the defect-free separation layer is the first pursuit of membranes based on high free volume polymers in recent years.