Membranes Based on Polymers with Long Alkyl Side-Chains

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Abstract Proposal No: 9714305 Proposal Type: Investigator Initiated Principal Investigator: Donald R. Paul Affiliation: University of Texas at Austin This grant is awarded through the Separations and Purification Program sub-element of the Interfacial, Transport and Separations Program of the Chemical and Transport Systems Division. The principal investigator is Dr. Donald Paul at the University of Texas at Austin. The research is directed at the development of membrane materials that have temperature induced changes in permeability. This is a novel approach where the permeability is not a smoothly increasing function of temperature but a rather a situation where a small temperature change can serve as a switch for substantial permeability changes. These temperature induced switches in permeability are brought about by the use of polymers containing alkyl side chain that crystallize relatively independent of the polymer backbone. When the material is heated up beyond the glass transition temperature of the side chains, the loss of crystallinity opens up transport pathways and increases the permeability. The switch from a permeable to a relatively nonpermeable membrane occurs across the glass transition temperature of the side chains. There are several significant applications of such temperature induced permeability switches. Amongst the most interesting is the potential to use seasonal changes in temperature to release agricultural agents such as pesticides of fertilizers. The temperature switches can also be used to deliver drugs when these drugs are placed in capsules make from these polymeric materials. The concepts presented here represent frontier areas of polymer membrane research.