Light Controls New Membrane’s Permeability

First there was light. Then gas flowed. And mankind was happy.

Graduate student Eric Glowacki and his team of researchers from The University of Rochester have developed a scientific first. Their new membrane allows gas to flow through it when one color of light is shined upon it. It blocks the same gas when a light with a different color is used.

The membrane is made of a circular chip of hard plastic. Tiny, evenly-spaced tunnels about a hundredth of a millimeter in diameter are created by bombarding it with neutron beams. These are then filled with liquid crystals and a dye. Excess liquid crystals are removed from the surface using a centrifuge.

The dye reacts to purple light by straightening its molecules and aligning the liquid crystals, allowing gas to flow through the tunnels. When UV light is used, the dye molecules change shape and scatter the liquid crystals in random orientations, effectively blocking the gas.

This method is preferable to using electricity or heat, says Glowacki. Light can be shone remotely onto the surface, instead of making complex mechanisms for distributing heat or electricity. Repeated applications of heat can also damage materials and it takes time for a material to cool down. Light will not ignite gas, making research on hydrocarbons and other flammable gas easy. The needed energy for the light is also way smaller.

There are various potential uses for the membrane, ranging from controlled drug delivery to industrial processing tasks to research applications.

Via Futurity