Abstract
Biological membranes possess sophisticated functionalities such as selective ion and water molecule transport, signal transduction, reaction field, and so on. “Bioinspired material” is a material that reconstructs such functionalities artificially. As such material, gating membrane exhibited ON/OFF switching behavior in response to external stimuli, e.g. temperature, pH, electric field, magnetic field, and specific ions and molecules. This kind of bioinspired channel can be fabricated by grafting stimuli–responsive polymer onto the pore surface of porous substrate. To attain steeper gating behavior, the grafted polymer should be long enough for filling the pore in OFF state. The plasma graft polymerization technique can fabricate graft polymer with ultra–high molecular weight more than 1,000,000 g/mol. Furthermore, by grafting the ultra–high molecular weight ion recognition polyampholyte on the porous substrate, specific membrane that can control its permeability in response to both of pH and specific ion (such as K+ and Ba2+) can be fabricated. In the present study, the fabrication mechanism of the ultra–high molecular weight graft polymer, and specific behavior of the ion recognition polyampholyte membrane is reported.
