ABSTRACT
This chapter focuses on applications of conjugated polymers for selected separations. It introduces conjugated polymer–based gas separation membranes using polyaniline, followed by the use of other conjugated polymers and then composite membranes. The chapter discusses conjugated polymer–based membranes for water purification, followed by the emerging field of capacitive deionization. It highlights the synthesis, mechanisms, and performances of membrane technologies that specifically use conjugated polymers. The driving forces for separation can be the gradients of concentration, temperature, pressure, and/or external/internal electric potential. Polymeric membranes used for gas separations can be categorized into two types: rubbery polymers and glassy polymers. Gas molecules are small in size; hence, making a sufficiently dense polymeric membrane with angstrom-size pores for gas separation is crucial. For an as-cast membrane, the permeability of gases mainly depends on the kinetic diameter of the gas molecules due to the effect of molecular sieving.
