Poly(ether ether ketone) derivative membranes - a review of their preparation, properties and potential

The present paper gives an overview of the properties and performance of membranes of a poly(ether ether ketone) derivative with a cardo group in the chain, known in the literature as PEEKWC or PEK-C. This is one of the typical examples of a new polymer, emerged in the last two decades, with the potential to be applied as a membrane material in a wide range of application fields. Due to the presence of the cardo group in the backbone, the polymer is soluble in several common organic solvents, in contrast to the traditional poly(ether ketone) (PEK) and poly(ether ether ketone) (PEEK). It is therefore much versatile and its solubility allows the use of nonsolvent-induced phase inversion techniques to prepare membranes with a wide range of different morphologies and transport characteristics. The present review will show the current state of the art and will testify that PEEKWC offers interesting perspectives in especially the fields of gas separation, biomedical applications and - in its sulfonated form - in fuel cells. Examples of successful application in microfiltration, ultrafiltration, nanofiltration, pervaporation, membrane contactors, catalytic membranes and some other applications, such as packaging and molecular imprinting will also be shown.