PHOTOREVERSIBLE POLYMERIC MEMBRANES

A variety of advances have been made in the use of environmental factors to control the separation characteristics of polymeric membranes in real time. These systems work by incorporating membrane materials which respond to external stimuli such as temperature or pH by making changes in conformation, solubility, or phase. In this review we focus on the use of light (photons) as the external control stimulus. Specifically, we examine the ability to control polymeric membrane properties by incorporating reversible photochromic moieties into the polymer structure. The first section is a brief review of the chemistry of photochromic compounds, the second section focuses on photocontrol of the separation properties of nonporous and hydrogel membranes, and the third section discusses the photocontrol of release rates from synthetic bilayer membranes.