First Membrane Controlled By Light Developed

An anonymous reader writes with this excerpt: "A new membrane developed at the University of Rochester's Laboratory for Laser Energetics blocks gas from flowing through it when one color of light is shined on its surface, and permits gas to flow through when another color of light is used. It is the first time that scientists have developed a membrane that can be controlled in this way by light."

Imagine a new heart valve

[bknack]

I don't know why, but the first thing that came to my mind is that perhaps this could be used in an artificial heart. No moving parts (the valves anyway) and precise low power way to block and allow blood flow. Hmm...

Locks On/Off

[Doc Ruby]

Something interesting about these optically-actuated gateways is that they are (more or less) locked to open or closed by each of the different frequency "keys" shifting their state, not requiring continuous illumination:

When purple light illuminates the surface of the membrane, the dye molecules straighten out and the liquid crystals fall into line, which allows gas to easily flow through the holes. But when ultraviolet light illuminates the surface, the dye molecules bend into a banana shape and the liquid crystals scatter into random orientations, clogging the tunnel and blocking gas from penetrating.

When the gas that the membrane controls can be made to emit one or another of the frequencies when its physical or chemical properties change, this material will become a "gas transistor", which will allow gas to control its own distribution determined by what physical/chemical state it's in.