Membrane makes light work of gas separation.(Molecular valve)

Scientists have developed a light-controllable molecular valve to regulate the flow of gases. The liquid crystal device uses dye molecules to change its structure to allow gas molecules to pass through the material. The valve could be ideal for microreactors or the basis of an explosion proof device to handle flammable gases.

The researchers used an azobenzene dye containing a dinitrogen double bond. The dye changes configuration on exposure to UV light and this disrupts the ordering of the liquid crystal, allowing molecules to pass through. Another wavelength converts it back, closing the valve (Advanced Functional Materials, doi: 10.1002/adfm.201000551).

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