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

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

PrimaPak targets younger consumers

December 24, 2014 10:22 am ET

PrimaPak, which combines attributes of both rigid and flexible packaging, is being aimed squarely at younger folks — including millennials and...    More

Image

French investment firm buys Vienna-based Constantia Flexibles

December 23, 2014 3:03 pm ET

Constantia Flexibles GmbH, one of Europe's largest flexible packaging companies, has a new owner.    More

Image

Duro-Last's large new extruder brings more under its own roof

December 22, 2014 3:24 pm ET

Roofing systems maker Duro-Last Inc. says it installed a one-of-a-kind extruder at its facility in Buena Vista Township, Mich., that is 5-stories...    More

Image

Piedmont moves to larger location

December 22, 2014 2:04 pm ET

Piedmont Plastics Inc. is moving to a larger location to serve the plastic sheet, rod, tube and film markets in the Philadelphia area.    More

Image

Alex Brands buys iconic Shrinky Dinks toys

December 19, 2014 3:15 pm ET

First Slinky, now Shrinky Dinks. What will toy and games investment firm Alex Brands buy next?    More

Market Reports

Flexible Packaging Trends in North America

Our latest RESEARCH report examines trends in FLEXIBLE PACKAGING impacting the North American market including a review of economic conditions, key drivers of growth, materials pricing, M&A activity, sustainability challenges and the outlook for 2015.

Learn more

Plastics in Brazil - State of the Industry Report

This in-depth report examines the Brazilian plastics industry from a historical and geographical context. Our analysts provide insight on economic trends and forecasts, growing manufacturing sectors that utilize plastics, private investment opportunities, market environment challenges, and innovations in R&D.

Data tables and charts on producer prices, trade, plastics production and end market indicators is also included.

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

Upcoming Plastics News Events

January 14, 2015 - January 14, 2015Plastics in Automotive

February 4, 2015 - February 6, 2015Plastics News Executive Forum 2015

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

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

October 27, 2015 - October 29, 2015Plastics Financial Summit - New York - 2015

More Events