Manipulating liquid crystals for better food packaging

A new method for manipulating the molecules of liquid crystals in ways previously unachieved could result in more effective industrial sealants, improved food packaging and even enhanced electronic displays, says Zhengdong Cheng, a Texas A&M University assistant professor of chemical engineering and member of a team of researchers whose recent findings hail a significant advancement in working with liquid crystals.

According to the university’s news writer Ryan A. Garcia, the findings, which appear in the scientific journal Physical Review E, detail how Cheng and his colleagues were able to orient the disc-shaped molecules of liquid crystals into distinct and separate layers – a phenomenon labeled by scientists as a “smectic phase.”

This layering phase, Cheng explains, is common with rod-shaped liquid crystal molecules but had never been recorded with their disc-shaped counterparts – until now.

“Before this, no discotic smectic phase was known to exist,” Cheng said. “For some time, people have been really puzzled as to why the discs don’t form layers.”

The discovery could mean expanded possibilities for the already popular material.

Liquid crystals are a state of matter between that of a conventional liquid and that of a solid crystal.

Possessing inherent properties that are ideal for working with light as well as a molecular structure that can be easily controlled by electric fields, liquid crystals are commonly used in the electronic displays of televisions, cell phones and portable gaming devices.

Liquid crystals are also found in soaps and detergents as well as in the proteins and cell membranes within the human body.

Key to Cheng’s discovery is the shape of the liquid crystal molecules he used.

The disc-shaped nature of the platelets in combination with the layered structure they form help to create a near-impermeable sealant.

Integrating such a sealant into food packaging would translate into foods staying fresher for longer periods of time, Cheng says.