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Photo-switchable membrane and method

United States Patent

May 7, 2013
View the Complete Patent at the US Patent & Trademark Office
Switchable gas permeation membranes in which a photo-switchable low-molecular-weight liquid crystalline (LC) material acts as the active element, and a method of making such membranes. Different LC eutectic mixtures were doped with mesogenic azo dyes and infused into track-etched porous membranes with regular cylindrical pores. Photo-induced isothermal phase changes in the imbibed mesogenic material afforded large, reversible changes in the permeability of the photo-switchable membrane to nitrogen. For example, membranes imbibed with a photo-switchable cyanobiphenyl LC material demonstrated low permeability in the nematic state, while the photo-generated isotropic state demonstrated a 16.times.-greater sorption coefficient. Both states obey a high linear sorption behavior in accordance with Henry's Law. In contrast, membranes imbibed with a photo-switchable phenyl benzoate LC material showed the opposite permeability behavior to the biphenyl-imbibed membrane, along with nonlinear sorption behavior.
Marshall; Kenneth L. (Rochester, NY), Glowacki; Eric (Marlboro, NJ)
University of Rochester (Rochester, NY)
13/ 195,508
August 1, 2011
FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT The U.S. Government grant(s) relating to this invention that may be required to be set forth in this document are as follows: Award Grant No. DE-FC52-08NA28302 awarded by the United States Department of Energy. The United States government has certain rights in this invention.