Synthesis of novel nanostructured mixed matrix membranes

The synthesis of novel nanostructured mixed matrix membranes is presented in this contribution. The concept is to embed a liquid in which eventually a carrier can be located, as microscopically small droplets in a polymeric matrix. Preparation of capsules by applying and modifying of traditional encapsulations routes is described in detail and a new method to prepare submicrometer-sized capsules based on interfacial crosslinking or copolymerisation is presented. In the last step, the capsules are embedded in a polymer matrix using a novel film formation technique: the capsules are dispersed in the monomer, which is subsequently polymerised.

A new method based on interfacial crosslinking or copolymerisation has been developed to prepare submicrometer-sized capsules that can be employed in the preparation of microencapsulated liquid membranes. To prepare the capsules an AB-type block copolymer surfactant (MMA10MAA8) was employed that consists of ten methylmethacrylate and eight methacrylic acid units. At high pH, MMA10MAA8 is soluble in water and stabilises w/o emulsions. Capsules were prepared by crosslinking the MAA groups of neighbouring surfactants with hexanediamine. To find the optimal conditions for the encapsulation process, emulsion formation and crosslinking were studied in detail. Submicrometer firm capsules were prepared that can easily be homogeneously embedded in a polymeric matrix obtained by polymerising a mixture of MMA and MAA and the dry dispersed capsules. Acknowledgments The authors are grateful to the Netherlands Foundation for Chemical Research (NWO–CW) in collaboration with the Netherlands Technology Foundation (STW) for financial support. R. Van Dijk and V. Tessera are thanked for their help in performing part of the experiments.