Scientists at the Laboratory for Laser Energetics of the
University of Rochester, Rochester, N.Y., have developed a
membrane that 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. Eric Glowacki, a
graduate student at the university, and Kenneth Marshall,
research engineer, optical materials, invented the membrane,
which reportedly is the first one whose permeability is
controlled by light. Applications could include those where gas
flow must be cycled on and off but where making electrical or
other hardware connections would be difficult. "Think in terms
of very small or micro-scale apparatus that would need gas
delivery — such as very small hand-held chemical analyzers,
medical equipment, complex process equipment, or even nano-scale
processes," says Marshall. Another possibility is the separation
of straight-chain from branched-chain hydrocarbons, he adds. The
researchers create 400-mm pores in a commerci