New liquid crystal could transform digital displays

Posted by Staff writer

Chemists at Vanderbilt University have created a new type of liquid crystals with unique electrical properties that they say could revolutionize digital displays.

They say they've applied for a patent on the technology, and have received interest from a number of commercial companies who are currently evaluating it.

"We have created liquid crystals with an unprecedented electric dipole, more than twice that of existing liquid crystals," says professor Piotr Kaszynski.

"Our liquid crystals have basic properties that make them suitable for practical applications, but they must be tested for durability, lifetime and similar characteristics."

Electric dipoles are created in molecules by the separation of positive and negative charges; and the stronger the charges and the greater the distance between them, the larger the electric dipole produced.

In liquid crystals, higher electric dipoles allow a lower threshold voltage: the minimum voltage at which the liquid crystal operates. In addition, at a given voltage, liquid crystals with higher dipoles switch faster than those with lower dipoles.

Thus, the new liquid crystals created by the team could be used for displays that operate at lower voltages.

What distinguishes the new class of liquid crystals, says the team, is its 'zwitterionic' structure. Zwitterions are chemical compounds that have a total net electrical charge of zero but contain positively and negatively charged groups.

The newly developed liquid crystals contain a zwitterion made up of a negatively charged inorganic portion and a positively charged organic portion.

The team says the discovery could have important scientific as well as commercial implications: for example, it is enabling the team to understand the effect that a liquid crystal's electric dipole has on the temperature at which it becomes an ordinary liquid.