H. (Hein) Verputten

Research description

Microfluidics integrated with ion selective slots for on chip electrodialysis

Membrane processes in which an electrical potential is used as the driving force has been verified for numerous ionic separations in the membrane field. Ion concentration polarization due to the applied electric field is a fundamental transport phenomenon, also encountered in classical membrane operations such as electrodialysis. With the advances in micro/nano fluidics, the overlap of electrical double layer can be realized, suggesting the opportunity of ionic separations on the micro-scale. The challenge is the implementation of electrically conductive membranes at the length scales offering the overlap of debye layers. For the integration of ion selective polymers into microfluidic devices, two kind of ion selective membranes can be distinguished; 1- the base polymer solution of the membrane require a thermal treatment or 2- the base polymer solution of the membrane require a photo- treatment. For the first kind, Nafion is commonly used in the membrane community. In microfluidics, nafion filled nanoslots are proposed to be used in desalination [1]. For the second kind, the charged polymers, suitable for photo-crosslinking, have a promising potential to be implemented on micro/nanofluidic devices using photolithographic methods. The copolymer of epichlorhydrin and allyl glycidyl ether (93/7, w/w) is potentially photo-crosslinkable and can have negative charge by amination reactions. The fabrication of microfluidic devices integrated with ion selective compartments and the proof of concept experiments is the challenge to propose on chip electrodialysis kind ionic separations.