Ink-jet printing assisted fabrication of patterned thin film composite membranes

Thin film composite membranes are used worldwide especially for desalination and water treatment. However, for effective water permeation, and to minimize fouling, feed water must be pre-treated before membrane treatment. Moreover, polymer degradation by oxidizing agents and the presence of undesirable elements such as boron in the permeate are persistent challenges. Novel membrane fabrication methods based on modern technologies may facilitate the creation of robust and selective polymer compositions and coatings. Here we explore the hybridization between ink-jet printing technology and the interfacial polymerization process. In this study, the patterned incorporation of a fluorinated diamine into an m-phenylenediamine-based polyamide yielded improved salt rejection that was explained in terms of increased selective layer hydrophobicity. Incorporation of the new fluorinated monomer, observed using FTIR and XPS, resulted in a more hydrophobic surface whose morphologies were similar to membranes lacking fluorine. The combination of printing technology with interfacial polymerization facilitated the fabrication of unique selective layers and demonstrated to be a potentially useful new laboratory membrane fabrication tool. Further development may accelerate the discovery of more efficient and robust membranes and promote the exploration of new material combinations, the potential of patterned compositions, and polymer morphologies that are not possible with conventional methods.