Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


Light-sensitive particles change chemistry at the flick of a switch


A light-sensitive, self-assembled monolayer that provides unique control over particle interactions has been developed by scientists at the University of Illinois at Urbana-Champaign. Particles coated with the monolayer change their surface charge and chemistry upon exposure to ultraviolet light.

"Tailoring interactions between particles allows us to design colloidal fluids, gels and crystals for use as ceramic, photonic and pharmaceutical materials," said Jeffrey Moore, a William H. and Janet Lycan Professor of Chemistry and a researcher at the Frederick Seitz Materials Research Laboratory and at the Beckman Institute for Advanced Science and Technology. "We are assembling a toolkit of molecules that can be incorporated as monolayers on particles to achieve desired effects."

Light-induced modification of colloidal interactions provides an ’extra handle’ for tailoring system behavior, said Jennifer Lewis, the Thurnauer Professor of Materials Science and Engineering and interim director of the Frederick Seitz Materials Research Laboratory.

"The monolayer is designed so that light triggers the cleavage of a specific chemical bond, thereby exposing an underlying functional group of interest," said Lewis, who also is a professor of chemical and biomolecular engineering and a researcher at the Beckman Institute.

Moore and Lewis first demonstrated the technique in a paper published in the Sept. 30, 2005, issue of the Journal of the American Chemical Society. In that work, the surface charge and, thus, the electrostatic interactions between photosensitive silica microspheres, were modified by exposure to ultraviolet light.

In recent work, the researchers documented the gel-to-fluid transition in binary mixtures that initially were oppositely charged. "Exposure to ultraviolet light rendered all of the particles negative and converted the system into a colloidal fluid that settled to form a dense sediment," said Moore, who will present the team’s findings at the national meeting of the American Chemical Society, to be held in Atlanta, March 26-30.

"These light-responsive systems will enable novel assembly routes for creating colloidal structures in a variety of materials," Lewis said. "We are currently investigating the ability to locally photo-pattern such assemblies in three dimensions without requiring multiple processing steps."

Light-sensitive colloidal particles could also be used to "tune" the elastic properties, viscous response and microstructure of gel-based inks used in the direct-write assembly of complex, three-dimensional structures formed by robotic deposition.

The Moore group is developing multiple wavelength-specific triggers that would allow different wavelengths of light to induce changes sequentially.

James E. Kloeppel | EurekAlert!
Further information:

More articles from Physics and Astronomy:

nachricht Light-driven atomic rotations excite magnetic waves
24.10.2016 | Max-Planck-Institut für Struktur und Dynamik der Materie

nachricht Move over, lasers: Scientists can now create holograms from neutrons, too
21.10.2016 | National Institute of Standards and Technology (NIST)

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Light-driven atomic rotations excite magnetic waves

Terahertz excitation of selected crystal vibrations leads to an effective magnetic field that drives coherent spin motion

Controlling functional properties by light is one of the grand goals in modern condensed matter physics and materials science. A new study now demonstrates how...

Im Focus: New 3-D wiring technique brings scalable quantum computers closer to reality

Researchers from the Institute for Quantum Computing (IQC) at the University of Waterloo led the development of a new extensible wiring technique capable of controlling superconducting quantum bits, representing a significant step towards to the realization of a scalable quantum computer.

"The quantum socket is a wiring method that uses three-dimensional wires based on spring-loaded pins to address individual qubits," said Jeremy Béjanin, a PhD...

Im Focus: Scientists develop a semiconductor nanocomposite material that moves in response to light

In a paper in Scientific Reports, a research team at Worcester Polytechnic Institute describes a novel light-activated phenomenon that could become the basis for applications as diverse as microscopic robotic grippers and more efficient solar cells.

A research team at Worcester Polytechnic Institute (WPI) has developed a revolutionary, light-activated semiconductor nanocomposite material that can be used...

Im Focus: Diamonds aren't forever: Sandia, Harvard team create first quantum computer bridge

By forcefully embedding two silicon atoms in a diamond matrix, Sandia researchers have demonstrated for the first time on a single chip all the components needed to create a quantum bridge to link quantum computers together.

"People have already built small quantum computers," says Sandia researcher Ryan Camacho. "Maybe the first useful one won't be a single giant quantum computer...

Im Focus: New Products - Highlights of COMPAMED 2016

COMPAMED has become the leading international marketplace for suppliers of medical manufacturing. The trade fair, which takes place every November and is co-located to MEDICA in Dusseldorf, has been steadily growing over the past years and shows that medical technology remains a rapidly growing market.

In 2016, the joint pavilion by the IVAM Microtechnology Network, the Product Market “High-tech for Medical Devices”, will be located in Hall 8a again and will...

All Focus news of the innovation-report >>>



Event News

#IC2S2: When Social Science meets Computer Science - GESIS will host the IC2S2 conference 2017

14.10.2016 | Event News

Agricultural Trade Developments and Potentials in Central Asia and the South Caucasus

14.10.2016 | Event News

World Health Summit – Day Three: A Call to Action

12.10.2016 | Event News

Latest News

The nanostructured cloak of invisibility

25.10.2016 | Life Sciences

Oasis of life in the ice-covered central Arctic

24.10.2016 | Earth Sciences

‘Farming’ bacteria to boost growth in the oceans

24.10.2016 | Life Sciences

More VideoLinks >>>