Chapter 11: Responsive Membranes

Interest in stimuli-responsive membranes has continued to grow over recent decades. A great deal of work has been devoted to developing environmentally sensitive materials and membranes that can be crafted into new smart products. In this chapter we aim to highlight recent results and possible trends that exploit stimuli responsive membranes. Significant opportunities exist for developing new responsive membranes for biomedical applications due to their specificity and the ability to respond to stimuli that are inherently present in living systems. Recent results in the area of synthetic polymeric membranes that respond to pH, solution ionic strength and biological cues are highlighted. Regarding biological cues, special attention is given to antigen-responsive, thiol-responsive, redox-responsive, enzyme-responsive and glucose-responsive membranes. Theoretical and simulation approaches to understand and optimize these stimuli-responsive membranes have just begun due to the inherent complexity involved in these systems. Here the pK_a calculations for pH responsive materials are summarized. In addition, one example of the effects of salt ions on responsive hydrogels is provided. The opportunity for modeling and simulations in responsive membranes is tremendous.