Vapor phase synthesis of smart membranes for macromolecule separation applications

Official URL: http://risc01.sabanciuniv.edu/record=b1669812 (Table of Contents)

Today, state-of-the-art synthesis and advanced purification at a reasonable price and in a short time is necessary to reach the high purity of molecules in chemicals and biochemical manufacturing industry. One of the most important methods is to use functional polymers in order to increase the permeability and selectivity of commonly used membranes. Smart membranes change their physicochemical properties in response to changes in their environment such as pH, temperature, ionic strength, light, electric and magnetic fields. The main goal of this thesis is to design and prepare different types of separation membranes via vapor polymerization methods to improve the permeability and selectivity of the membranes. Stimuli responsive polymers are used to functionalize the membranes for triggered control of permeation and tuning of the release kinetics. In the first chapter, nonporous, ultra-thin large area free-standing functional membranes are developed. The mesh size is tuned to control the permeability and selectivity of the membranes for separation of model dye molecules with different size and polarity. In the second part, hybrid membranes are produced by modifying AAO template pores using smart polymers. Shape, size and charge interactions between the membranes and macromolecules are the key factors in controlling the membrane selectivity via changing the membrane pore size at different pH values. Double-sided Janus membranes with two different pH responses are developed as gating membranes to control the flow of the protein molecules through the membrane. The key-shaped non-conformal coatings allow to control protein diffusion by blocking, delaying and releasing protein depending on the acidity of the medium. Furthermore, the shape of the nanochannels is another critical factor in separation of proteins by membranes. Membranes with symmetric cylindrical and asymmetric conical functionalized nanochannels are developed to control the protein flux and separation. Finally, negatively charged and neutral membranes are fabricated to separate two proteins with the same size but different charges using pH responsive polymers.