Researchers develop nanotech gels to monitor food freshness

James Snodgrass

Published: January 3, 2013 6:00 am ET

Related to this story

Topics Packaging Film & Sheet Design
Companies & Associations

HOUSTON (Jan. 3, 11:10 a.m. ET) — In the refrigerator of the future, we won’t be looking for “Use By” or “Best Before” dates. We will be able to tell whether food is fresh, or has turned for the worse, with a quick visual inspection.

In-mold labels made from a photonic gel will change color when exposed to chemicals associated with a foodstuff going off. So we will have an instant visual warning if our food’s gone bad.

This is just one of many applications for a novel, extremely thin color-changing films that have been developed by materials scientists at Rice University and the Massachusetts Institute of Technology. The research has been published in the nanotechnology journal of the American Chemical Society, ACS Nano.

Leading the project is Ned Thomas, dean of Houston-based Rice’s engineering school, and former chair of the department of materials science and engineering at MIT).

Thomas and his team have combined polymers into a self-assembled metamaterial that changes color when exposed to ions dissolved in solution — or ions in the environment at large. The material changes color according to the ions’ ability to penetrate the hydrophilic layers.

The micron-thick material, made from nanoscale layers of hydrophobic (water resisting) polystyrene and hydrophilic (water loving) poly(2-vinyl pyridine) (P2VP), is called a photonic gel. Thinner than a human hair, Thomas believes the photonic gels will be extremely inexpensive to produce.

“We could cover an area the size of a football field with this film for about $100,” Thomas said.

Exposing the films to various solutions, the researchers discovered that they changed color in proportion to the amount of solvent absorbed by the P2VP. From the film’s neutral, clear, state the researchers turned the film blue (using thiocyanate), green (iodine), yellow (nitrate), orange (bromine) and red (chlorine). All these interactions were reversible; the film returned to its transparent state in the absence of contaminants.

The change in color is caused by expansion of the P2VP layers. Different thicknesses of layers within the film change the way that light is refracted through the film. Thomas suggests that these changes can be exploited in such a way as to make gels that are “tuned” to react in specific ways.

Thomas said: “These days in photonics, people are thinking about light as though it were water. That is, you can put it in these tiny pipes. You can turn light around corners that are very sharp. You can put it where you want it, keep it from where you don’t want it. The plumbing of light has been much easier than in the past, due to photonics, and in photonic crystals, due to band gaps.”

Other potential applications for the technology include security (instant, visual testing for drugs, explosives or biological contaminants) or as an alternative technology to e-ink or thin film transistor displays.


Comments

Researchers develop nanotech gels to monitor food freshness

James Snodgrass

Published: January 3, 2013 6:00 am ET

Post Your Comments


Back to story


More stories

Image

Flextronics launches global injection molding, tooling unit

March 26, 2015 4:29 pm ET

Flextronics International Ltd. (Booth S34125) is officially launching Precision Plastics, a global injection tooling and manufacturing unit, as a...    More

Image

Kautex showing off an extrusion blow molding machine at NPE

March 25, 2015 6:00 am ET

After 80 years in business, Kautex Maschinenbau GmbH officials know good old-fashioned word of mouth is often the best way to reach more customers.    More

Image

Fabri-Kal to expand its sustainable packaging with new Idaho plant

March 20, 2015 2:03 pm ET

Thermoformed packaging company Fabri-Kal Corp. plans to tap into Idaho's farming community to expand its sustainable packaging program.    More

Silgan picks Hazelwood, Mo., for plant

March 20, 2015 11:32 am ET

Silgan Plastics has reportedly selected the location of its second new plastics container plant.    More

Image

Advances in barrier injection molding highlighted at NPE

March 17, 2015 10:39 am ET

It's a Holy Grail of plastics: Clear, coinjection molded containers to replace metal cans, the common “tin can” produced by the billions e...    More

Market Reports

Flexible Packaging Trends in North America

North America represents about 30 percent of the global consumption of flexible packaging. Annual growth in this region is forecast at 4 percent during the next 5 years.

For more insight on growth opportunities, drivers of growth and the outlook for 2015, download this report.

Learn more

Plastics Recycling Trends in North America

This report is a review and analysis of the North American Plastics Recycling Industry, including key trends and statistics based on 2013 performance. We examine market environment factors, regulatory issues, industry challenges, key drivers and emerging trends in post-consumer and post-industrial recycling.

Learn more

Plastics in Mexico - State of the Industry Report

This report analyzes the $20 billion plastics industry in Mexico including sales of machinery & equipment, resins and finished products.

Our analysts provide insight on business trends, foreign investment, top end markets and plastics processing activity. The report also provides important data on exports, production, employment and value of plastics products manufactured.

Learn more

Upcoming Plastics News Events

June 2, 2015 - June 3, 2015Plastics Financial Summit - Chicago 2015

September 16, 2015 - September 18, 2015Plastics Caps & Closures - September 2015

More Events