Neutron scattering provides window into surface interactions

Jan 17, 2012

To better understand the fundamental behavior of molecules at surfaces, researchers at the U.S. Department of Energy's Oak Ridge National Laboratory are combining the powers of neutron scattering with chemical analysis.

Scientists have a fundamental interest in how molecules behave at solid surfaces because surface interactions influence chemistry, such as in materials for catalysis, drug delivery and . Understanding these interactions allows researchers to tailor materials for a specific desirable outcome.

Michelle Kidder and A.C. Buchanan, physical organic chemists, and Ken Herwig, neutron scattering scientist, used neutron scattering to study the physical motion of a chemically attached organic molecule inside a silica nanopore, MCM41.

"There is a connection between a molecule's or motion to its surroundings." Herwig said. "In particular, restricting the ability of a molecule to freely move by confining it to a small volume dramatically affects both the range and character of its movement. We are trying to gain insight into the connection between the changes in molecular motion and the changes in chemistry that occur when molecules are attached to a ."

Herwig used neutron scattering to gain a unique perspective into because neutrons are sensitive to the , which are present in many molecules that researchers are interested in. Additionally, simultaneously tells researchers how rapid the motion is and what type of motion they are observing on the atomic and nanoscale.

If scientists understand how pore size affects surface interactions, they can modify pore size to change a chemical product outcome.

To study surface interactions, Kidder synthesized both the and MCM41 of different pore sizes, then chemically attached the molecules to the silica pore surface, which forms an organic-inorganic hybrid material. This hybrid material is used in studies to understand chemical decomposition pathways, where surface interactions were presumed to play a role.

"We are interested in understanding the thermo decomposition of molecules similar to those found in biomass resources," Kidder said. "What we have seen is that there are many local environmental factors that influence chemical reactivity and products, and one of those large influences occurs when a molecule is confined to a pore wall, where even the pore size has a large impact on reactivity."

Explore further: First in-situ images of void collapse in explosives

More information: These findings were published in a paper, "The Dynamics of 1, 3 diphenylpropane Tethered to the Interior Pore Surfaces of MCM-41," which appeared in J Physical Chemistry C.

Related Stories

Nanotube 'glow sticks' transform surface science tool kit

Jan 11, 2012

(PhysOrg.com) -- Many physical and chemical processes necessary for biology and chemistry occur at the interface of water and solid surfaces. Researchers at Los Alamos National Laboratory publishing in Nature ...

Moving polymers through pores

Jul 14, 2010

The movement of long chain polymers through nanopores is a key part of many biological processes, including the transport of RNA, DNA, and proteins. New research reported in The Journal of Chemical Physics, which ...

Organic Molecules Stay on Top

Nov 19, 2007

The van der Waals force, a weak attractive force, is solely responsible for binding certain organic molecules to metallic surfaces. In a model for organic devices, it is this force alone that binds an organic film to a metallic ...

Recommended for you

First in-situ images of void collapse in explosives

5 hours ago

While creating the first-ever images of explosives using an x-ray free electron laser in California, Los Alamos researchers and collaborators demonstrated a crucial diagnostic for studying how voids affect ...

New approach to form non-equilibrium structures

Jul 24, 2014

Although most natural and synthetic processes prefer to settle into equilibrium—a state of unchanging balance without potential or energy—it is within the realm of non-equilibrium conditions where new possibilities lie. ...

Nike krypton laser achieves spot in Guinness World Records

Jul 24, 2014

A set of experiments conducted on the Nike krypton fluoride (KrF) laser at the U.S. Naval Research Laboratory (NRL) nearly five years ago has, at long last, earned the coveted Guinness World Records title for achieving "Highest ...

User comments : 0