Polymer membranes separate two volumes of a phase with different composition and enable a mass transfer between them. The structure of polymer membranes can be porous or compact and symmetrical or asymmetrical.
Different substance separation processes such as gas separation, microfiltration, ion exchange, dialysis, pervaporation or ultrafiltration can be carried out with these membranes. The base polymer has to be adjusted to the separation criteria; the fluid properties (pH value, dissolvability and swellability) and service conditions (T, p). Frequently used matrix materials are for instance cellulose derivatives, polyolefins, polysulfones, fluoropolymers, silicones or polyurethanes.
Applications, for which special materials were developed:
particle separation (microfiltration membrane),
waterproof, breathable liner for outdoor clothing and personal protective equipment
water vapour-permeable roofing underlays