Developments in the structure and movement of liquid crystals may result in more effective sealant properties that prolong shelf life.

The research, conducted at Texas A&M University (TAMU) in the USA, involves layering disc, instead of rod, shaped molecules of liquid crystals in a form similar to the structures of nacre (see image above). The 2D disc shape is said to create stronger barrier properties with improved coverage and better alignment.

In this new discotic phase, proteins can be embedded into lipid bilayers that are
supported on the discs to create a ‘super sealant’. In addition, it can be developed into novel materials for display if an external field controls the layered structure.

‘The form of the discotic smectic phase is similar to the structure of nacre. You can appreciate their excellent sealant property by examining the iridescent internal layer of a seashell,’ says Assistant Professor, Zhendong Cheng, TAMU.

The liquid crystals used in this research are formed of a compound of zirconium phosphate.

The discotic smectic phase has long been elusive of observation and making high aspect ratio (diameter divided by thickness) discs has proved difficult.

The other obstacle is how to make the discs a uniform thickness, a challenge the scientists claim to have now overcome. ‘For larger aspect ratio discs, the concentration of the discs in the suspension required to form the smectic phase is lower. We have tried discs with aspect ratio 2-1000,’ says Cheng.

Alistair Irvine, Principal Consultant, PIRA International, comments, ‘The technology looks promising but before this happens the materials would have to be registered with the FDA in the USA or in the EU by the European Food Safety Authority (EFSA). One particular challenge might arise from the nanoscale of these materials. The EFSA are currently adopting a cautious case-by-case
approach to the registration of new food contact materials based on nanoscale particles. In November 2009, the European Commission asked EFSA to prepare a guidance document on how to assess potential risks of food-related uses of
nanotechnology.’

The team at TAMU has already begun testing the nanotechnology on cosmetic materials, by using the discs to protect oil from oxidant agents.