Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

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

28.03.2006


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:
http://www.uiuc.edu

More articles from Physics and Astronomy:

nachricht Significantly more productivity in USP lasers
06.12.2016 | Fraunhofer-Institut für Lasertechnik ILT

nachricht Shape matters when light meets atom
05.12.2016 | Centre for Quantum Technologies at the National University of Singapore

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: Significantly more productivity in USP lasers

In recent years, lasers with ultrashort pulses (USP) down to the femtosecond range have become established on an industrial scale. They could advance some applications with the much-lauded “cold ablation” – if that meant they would then achieve more throughput. A new generation of process engineering that will address this issue in particular will be discussed at the “4th UKP Workshop – Ultrafast Laser Technology” in April 2017.

Even back in the 1990s, scientists were comparing materials processing with nanosecond, picosecond and femtosesecond pulses. The result was surprising:...

Im Focus: Shape matters when light meets atom

Mapping the interaction of a single atom with a single photon may inform design of quantum devices

Have you ever wondered how you see the world? Vision is about photons of light, which are packets of energy, interacting with the atoms or molecules in what...

Im Focus: Novel silicon etching technique crafts 3-D gradient refractive index micro-optics

A multi-institutional research collaboration has created a novel approach for fabricating three-dimensional micro-optics through the shape-defined formation of porous silicon (PSi), with broad impacts in integrated optoelectronics, imaging, and photovoltaics.

Working with colleagues at Stanford and The Dow Chemical Company, researchers at the University of Illinois at Urbana-Champaign fabricated 3-D birefringent...

Im Focus: Quantum Particles Form Droplets

In experiments with magnetic atoms conducted at extremely low temperatures, scientists have demonstrated a unique phase of matter: The atoms form a new type of quantum liquid or quantum droplet state. These so called quantum droplets may preserve their form in absence of external confinement because of quantum effects. The joint team of experimental physicists from Innsbruck and theoretical physicists from Hannover report on their findings in the journal Physical Review X.

“Our Quantum droplets are in the gas phase but they still drop like a rock,” explains experimental physicist Francesca Ferlaino when talking about the...

Im Focus: MADMAX: Max Planck Institute for Physics takes up axion research

The Max Planck Institute for Physics (MPP) is opening up a new research field. A workshop from November 21 - 22, 2016 will mark the start of activities for an innovative axion experiment. Axions are still only purely hypothetical particles. Their detection could solve two fundamental problems in particle physics: What dark matter consists of and why it has not yet been possible to directly observe a CP violation for the strong interaction.

The “MADMAX” project is the MPP’s commitment to axion research. Axions are so far only a theoretical prediction and are difficult to detect: on the one hand,...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ICTM Conference 2017: Production technology for turbomachine manufacturing of the future

16.11.2016 | Event News

Innovation Day Laser Technology – Laser Additive Manufacturing

01.11.2016 | Event News

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

14.10.2016 | Event News

 
Latest News

NTU scientists build new ultrasound device using 3-D printing technology

07.12.2016 | Health and Medicine

The balancing act: An enzyme that links endocytosis to membrane recycling

07.12.2016 | Life Sciences

How to turn white fat brown

07.12.2016 | Health and Medicine

VideoLinks
B2B-VideoLinks
More VideoLinks >>>