A scientist from the University of Tsukuba’s Faculty of Basic and Applied Sciences has developed a method for producing electrically conductive polymers with a helical configuration. Using a liquid crystal as a template, he was able to make optically active polymers that can convert light into circular polarization (“Molecular crystals and liquid crystals”, “Optical self-amplification activity of reaction field induction during polymerization in liquid crystals”). This approach will help reduce the cost of smart displays.

A researcher at the University of Tsukuba is developing a method for creating optically active polymers using a spiral liquid crystal model that could allow future computer and television displays to operate on circularly polarized light.

Nowadays, a trip to the electronics store can be great if you have to walk down the aisle with the TV. Sizes of televisions have expanded significantly in recent years and prices have fallen. This is mainly due to the introduction of organic light-emitting devices (OLEDs), which are carbon-based polymers that can glow at tuned optical wavelengths.

These bonded polymers with alternating single and double bonds are electrically conductive and have colors that can be controlled by chemical doping with other molecules. Oxidation states can also be rapidly changed by electrical voltage, which affects their color.

However, future developments may require new materials that can take advantage of other optical properties such as circular polarization. Now, a University of Tsukuba researcher has presented a method of creating polymers surrounded in a helical configuration using a liquid crystal template.

“Polymers with both optical activity and luminescence function can emit light with circular polarization,” says Professor Hiromasa Goto.

Therefore, the process molecules of liquid crystals initially had a direct configuration. The addition of monomer molecules caused the liquid crystals to bend in a helical configuration. This gives the structure a “chirality” or handle, making it oriented either clockwise or counterclockwise. An electrical voltage was applied, which triggered the polymerization of the monomers. The liquid crystal template was then removed and the polymer left helically frozen. The polymer can convert linearly polarized light into circular polarization by breaking the mirror symmetry. Furan rings in the polymer not only contribute to electrical conductivity, but also help stabilize the spiral structure.

“The pi-stacking interactions between the rings allow the polymer to assemble into a highly ordered chiral system,” says Professor Goto.

The resulting polymer was tested using circular dichroism absorption spectroscopy and was found to have strong optical activity in the visible wavelength range. Future programs in this process may include cheaper and more energy efficient electronic displays. Source