Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Brighter inks, without pigment: Nanostructured capsules could bring about paints and electronic displays that never fade

These photonic microcapsules have been prepared to produce blue, green, and red structural colors and imaged using bright-field (top) and dark-field (bottom) optical microscopy. Images courtesy of Jin-Gyu Park.
These photonic microcapsules have been prepared to produce blue, green, and red structural colors and imaged using bright-field (top) and dark-field (bottom) optical microscopy.

Images courtesy of Jin-Gyu Park.

Abstract:
Among the taxidermal specimens in Harvard's Museum of Comparative Zoology, past centuries-old fur coats, arises a flicker of brilliant blue. This is the spangled cotinga. Surprisingly, the cotinga is about as old as everything in the room, but its color is still as dazzling as the day it was brought to the museum. The cotinga—or rather its feathers—achieve this effect through structural color.

Brighter inks, without pigment: Nanostructured capsules could bring about paints and electronic displays that never fade

Cambridge, MA | Posted on March 14th, 2014

Unlike color that we usually think of, which arises from paints and dyes absorbing certain wavelengths of light and reflecting the remainder, structural color is created when an object's very nanostructure amplifies a specific wavelength. Cells in the cotinga's feathers have a series of tiny pores spaced just right so that blues (and not much of anything else) are reflected back to our eyes. Because of this, if the feathers were thoroughly pulverized, the formation of pores and therefore the color would be lost. It also means that the same color could be produced from an entirely different material, if one could recreate the same pattern made by the feathers' pores.

Researchers led by Vinothan N. Manoharan at the Harvard School of Engineering and Applied Sciences want to recreate this effect, giving man-made materials structural color. Producing structural color is not easy, though; it often requires a material's molecules to be in a very specific crystalline pattern, like the natural structure of an opal, which reflects a wide array of colors. But the pores on the cotinga's feathers lack a regular order and are therefore a prime target for imitation.

Manoharan's lab has devised a system where microcapsules are filled with a disordered solution of even smaller particles suspended in water. When the microcapsule is partly dried out, it shrinks, bringing the particles closer and closer together. Eventually the average distance between all the particles will give rise to a specific reflected color from the capsule. Shrink the capsule a bit more, and they become another color, and then another.

"There's an average distance between particles, even though there is no ordering in the particles. It's that average distance that is important in determining the color," says Manoharan, Gordon McKay Professor of Chemical Engineering and Professor of Physics at Harvard.

The current project expands on research conducted at Yale University in 2009, which aimed to mimic the cotinga's hue and showed that dried aggregates of solid particles could create blues. Jin-Gyu Park was a postdoctoral researcher there and is now a research associate in Manoharan's group at Harvard SEAS, which specializes in the physics of colloidal suspensions. With Park as lead author, the new paper demonstrates the production of colors across the spectrum, and the new encapsulation system.
The tunable color capsules present interesting technological opportunities, says Manoharan. For example, a whole spectrum of new paints might be created using suspended capsules.

"Right now, the red dye carmine comes from an insect called a cochineal," says Manoharan. "People would like to move away from that because it's very labor-intensive, and getting that color involves harvesting a lot of insects."

Rather than harvesting from nature or preparing specialty chemicals, one for each color, these capsules could provide a universal and direct path to any desired color.

The capsules might also offer a safety advantage. The reason for using natural dyes like carmine is that many synthetic dyes are toxic. The new color capsules can be made with particles of almost any material in the right structural formation, so toxicity can be easily avoided.

Most compelling of all, however, is that some structural colors found in nature can last indefinitely as long as the colored object remains intact.

"Most color you get in paints, coatings or cosmetics, even, comes from the selective absorption and reflection of light. What that means is that the material is absorbing some energy, and that means that over time, the material will fade," says Manoharan.
The sun's energy pummels the molecules in conventional pigments. Eventually, the molecules simply deteriorate and no longer absorb the colors they used to, leading to sun bleaching. Manoharan's group is currently testing their innovation to see if it can create an effectively ageless color.

Electronic display technology—for example, e-readers—might also benefit from this advance. The microcapsules could be used in displays that create pixels with colored particles rather than LEDs, liquid crystals, or black-and-white "electronic ink."

"We think it could be possible to create a full-color display that won't fade over time," says Manoharan. "The dream is that you could have a piece of flexible plastic that you can put graphics on in full color and read in bright sunlight."

The Harvard Office of Technology Development has filed a provisional patent and is working with Manoharan's lab to pursue the commercialization of the color capsule technology.

Manoharan's and Park's coauthors were Sofia Magkiriadou, a Ph.D. student in physics at the Harvard Graduate School of Arts and Sciences; Shin-Hyun Kim and Tae Min Choi at the Korea Advanced Institute of Science and Technology; and Young-Seok Kim at Korea Electronics Technology Institute.

This research was supported by an International Collaboration grant from the Ministry of Trade, Industry & Energy of Korea, and by the Harvard Materials Research Science and Engineering Center through the U.S. National Science Foundation (NSF). The work was performed in part at the NSF-supported Center for Nanoscale Systems at Harvard University.

####

For more information, please click here

Contacts:
Paul Karoff

617-496-0450

Copyright © Harvard University

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related Links

The findings have been published in the journal Angewandte Chemie:

Related News Press

News and information

Nanotube fiber antennas as capable as copper: Rice University researchers show their flexible fibers work well but weigh much less October 23rd, 2017

Arrowhead Presents Promising Preclinical Data on Development of ARO-AAT for Treatment of Alpha-1 Liver Disease at Liver Meeting(R) 2017 October 23rd, 2017

A step closer to understanding quantum mechanics: Swansea University’s physicists develop a new quantum simulation protocol October 22nd, 2017

Creation of coherent states in molecules by incoherent electrons October 21st, 2017

Display technology/LEDs/SS Lighting/OLEDs

The secret to improving liquid crystal's mechanical performance: Better lubricating properties of lamellar liquid crystals could stem from changing the mobility of their structural dislocations by adding nanoparticles October 13th, 2017

Missing atoms in a forgotten crystal bring luminescence October 10th, 2017

The power of perovskite: OIST researchers improve perovskite-based technology in the entire energy cycle, from solar cells harnessing power to LED diodes to light the screens of future electronic devices and other lighting applications August 18th, 2017

Nanocrystalline LEDs: Red, green, yellow, blue ... August 7th, 2017

Govt.-Legislation/Regulation/Funding/Policy

Nanotube fiber antennas as capable as copper: Rice University researchers show their flexible fibers work well but weigh much less October 23rd, 2017

Leti Coordinating Project to Develop Innovative Drivetrains for 3rd-generation Electric Vehicles: CEA Tech’s Contribution Includes Liten’s Knowhow in Magnetic Materials and Simulation And Leti’s Expertise in Wide-bandgap Semiconductors October 20th, 2017

Bringing the atomic world into full color: Researchers turn atomic force microscope measurements into color images October 19th, 2017

Long nanotubes make strong fibers: Rice University researchers advance characterization, purification of nanotube wires and films October 17th, 2017

Discoveries

Nanotube fiber antennas as capable as copper: Rice University researchers show their flexible fibers work well but weigh much less October 23rd, 2017

A step closer to understanding quantum mechanics: Swansea University’s physicists develop a new quantum simulation protocol October 22nd, 2017

Creation of coherent states in molecules by incoherent electrons October 21st, 2017

Strange but true: turning a material upside down can sometimes make it softer October 20th, 2017

Materials/Metamaterials

Strange but true: turning a material upside down can sometimes make it softer October 20th, 2017

MIPT scientists revisit optical constants of ultrathin gold films October 20th, 2017

Long nanotubes make strong fibers: Rice University researchers advance characterization, purification of nanotube wires and films October 17th, 2017

The secret to improving liquid crystal's mechanical performance: Better lubricating properties of lamellar liquid crystals could stem from changing the mobility of their structural dislocations by adding nanoparticles October 13th, 2017

Announcements

Nanotube fiber antennas as capable as copper: Rice University researchers show their flexible fibers work well but weigh much less October 23rd, 2017

Arrowhead Presents Promising Preclinical Data on Development of ARO-AAT for Treatment of Alpha-1 Liver Disease at Liver Meeting(R) 2017 October 23rd, 2017

A step closer to understanding quantum mechanics: Swansea University’s physicists develop a new quantum simulation protocol October 22nd, 2017

Creation of coherent states in molecules by incoherent electrons October 21st, 2017

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals/White papers

Nanotube fiber antennas as capable as copper: Rice University researchers show their flexible fibers work well but weigh much less October 23rd, 2017

A step closer to understanding quantum mechanics: Swansea University’s physicists develop a new quantum simulation protocol October 22nd, 2017

Creation of coherent states in molecules by incoherent electrons October 21st, 2017

Strange but true: turning a material upside down can sometimes make it softer October 20th, 2017

Home

Rice lab expands palette for color-changing glass: Nanophotonics team creates low-voltage, multicolor, electrochromic glass March 8th, 2017

Chemists Cook up New Nanomaterial and Imaging Method: Nanomaterials can store all kinds of things, including energy, drugs and other cargo January 19th, 2017

Industrial Nanotech, Inc. Announces Plans to Spin Off New Product Line to Major Paint Compan November 9th, 2016

New flexible material can make any window 'smart' August 23rd, 2016

Industrial

Novel 'converter' heralds breakthrough in ultra-fast data processing at nanoscale: Invention bagged four patents and could potentially make microprocessor chips work 1,000 times faster October 20th, 2017

Injecting electrons jolts 2-D structure into new atomic pattern: Berkeley Lab study is first to show potential of energy-efficient next-gen electronic memory October 13th, 2017

A flexible new platform for high-performance electronics September 29th, 2017

GLOBALFOUNDRIES Announces Availability of Embedded MRAM on Leading 22FDX® FD-SOI Platform: Advanced embedded non-volatile memory solution delivers ‘connected intelligence’ by expanding SoC capabilities on the 22nm process node September 20th, 2017

Research partnerships

Nanotube fiber antennas as capable as copper: Rice University researchers show their flexible fibers work well but weigh much less October 23rd, 2017

Novel 'converter' heralds breakthrough in ultra-fast data processing at nanoscale: Invention bagged four patents and could potentially make microprocessor chips work 1,000 times faster October 20th, 2017

Strange but true: turning a material upside down can sometimes make it softer October 20th, 2017

Leti Coordinating Project to Develop Innovative Drivetrains for 3rd-generation Electric Vehicles: CEA Tech’s Contribution Includes Liten’s Knowhow in Magnetic Materials and Simulation And Leti’s Expertise in Wide-bandgap Semiconductors October 20th, 2017

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project