Nanotechnology Now

Our NanoNews Digest Sponsors



Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > A Molecular ‘Salve’ to Sooth Surface Stresses

NIST researchers measured the surface stress of a monolayer film on gold by measuring the changing curvature of a gold-coated glass cantilever as molecules of mercaptobenzoic acid were deposited on the gold. The change in curvature was detected by the shifting reflection of a laser beam impinging onto the back side of the glass.

Credit: NIST
NIST researchers measured the surface stress of a monolayer film on gold by measuring the changing curvature of a gold-coated glass cantilever as molecules of mercaptobenzoic acid were deposited on the gold. The change in curvature was detected by the shifting reflection of a laser beam impinging onto the back side of the glass.
Credit: NIST

Abstract:
Researchers at the National Institute of Standards and Technology (NIST) have shown for the first time that a single layer of molecular "salve" can significantly soothe the stresses affecting clean metal surfaces. The discovery, revealed in a new paper,* may help scientists to understand the factors that influence surface stress, which is important in a broad array of applications from chemical and biological sensors to semiconductor manufacturing and metal plating.

A Molecular ‘Salve’ to Sooth Surface Stresses

GAITHERSBURG, MD | Posted on May 29th, 2008

Because the atoms on a clean metal surface are not bound on all sides, they are much more strongly bonded to each other than to the atoms beneath them. Atoms in a block of metal are like a big family, relaxed when surrounded by kinfolk. But when the metal is cut, the atoms exposed at the surface cling tighter to the siblings at their sides and draw closer together. That creates surface stress and causes the edges to curl and pull in toward the center of the surface.

Materials scientists generally believed that a single layer of molecules coating the surface would reduce the stress, but no tests had ever been performed to determine whether or not that actually happens. NIST researchers devised an elegant, highly sensitive experiment to measure the phenomenon using a 6-cm long, 0.3-cm wide and approximately 100-micron-thick gold-coated glass cantilever and a "salve" of mercaptobenzoic acid, a carbon-based sulfur-containing compound used for manufacturing such products as pharmaceuticals and agricultural chemicals. The "salve" forms a well-organized single layer (monolayer) on gold, and it forms a model system for measuring variations in surface stress. The team repeatedly deposited and removed the monolayer and monitored the curvature of the glass with a laser as the stress increased and decreased. The technique enabled them to record forces of less than 50 micronewtons per meter.

According to Chris Zangmeister, an author of the study, in addition to confirming that the application of a monolayer did reduce surface stresses, the team also discovered that the longer the molecules were allowed to sit the more comfortable they became with their new surroundings. As the monolayer became more comfortable, it became more stable, and the atoms in the metal began to adopt the molecules into the family, which substantially reduced the surface stresses.

The findings provide a deeper understanding of the forces at work at the interface of molecules and surfaces. Most notably the discovery could be used to create a new generation of chemical and biological sensors. Zangmeister says that these sensors would use molecular monolayers deposited on metal surfaces that are manufactured to react in the presence of chemical or biological agents in the environment. The activation of the monolayer would provide a proportional response to the amount of the substance it was designed to detect, which would result in a quantifiable decrease in the tension of the cantilever.

The findings appeared online in Electrochimica Acta in December and will appear as an invited paper in a special print issue of that same publication.

* C.D. Zangmeister, U. Bertocci, C.R. Beauchamp and G.R. Stafford. In situ stress measurements during the electrochemical adsorption/desorption of self-assembled monolayers. Electrochimica Acta. In press. The online version of the paper will be available until it is printed.

####

About NIST
From automated teller machines and atomic clocks to mammograms and semiconductors, innumerable products and services rely in some way on technology, measurement, and standards provided by the National Institute of Standards and Technology.

Founded in 1901, NIST is a non-regulatory federal agency within the U.S. Department of Commerce. NIST's mission is to promote U.S. innovation and industrial competitiveness by advancing measurement science, standards, and technology in ways that enhance economic security and improve our quality of life.

For more information, please click here

Contacts:
Mark Esser

(301) 975-8735

Copyright © NIST

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 News Press

News and information

Switching to spintronics: Berkeley Lab reports on electric field switching of ferromagnetism at room temp December 17th, 2014

ORNL microscopy pencils patterns in polymers at the nanoscale December 17th, 2014

Unraveling the light of fireflies December 17th, 2014

First Home-Made Edible Herbal Nanodrug Presented to Pharmacies across Iran December 17th, 2014

Chip Technology

Switching to spintronics: Berkeley Lab reports on electric field switching of ferromagnetism at room temp December 17th, 2014

Pb islands in a sea of graphene magnetise the material of the future December 16th, 2014

Stanford team combines logic, memory to build a 'high-rise' chip: Today circuit cards are laid out like single-story towns; Futuristic architecture builds layers of logic and memory into skyscraper chips that would be smaller, faster, cheaper -- and taller December 15th, 2014

Stacking two-dimensional materials may lower cost of semiconductor devices December 11th, 2014

Sensors

Promising new method for rapidly screening cancer drugs: UMass Amherst researchers invent fast, accurate new nanoparticle-based sensor system December 15th, 2014

Graphene Applied in Production of Recyclable Electrodes December 13th, 2014

Detecting gases wirelessly and cheaply: New sensor can transmit information on hazardous chemicals or food spoilage to a smartphone December 8th, 2014

Nanosensor to Detect Naproxen Drug Produced in Iran December 6th, 2014

Discoveries

Switching to spintronics: Berkeley Lab reports on electric field switching of ferromagnetism at room temp December 17th, 2014

ORNL microscopy pencils patterns in polymers at the nanoscale December 17th, 2014

Unraveling the light of fireflies December 17th, 2014

Fraud-proof credit card possible because of quantum physics December 16th, 2014

Materials/Metamaterials

ORNL microscopy pencils patterns in polymers at the nanoscale December 17th, 2014

Pb islands in a sea of graphene magnetise the material of the future December 16th, 2014

Graphene Applied in Production of Recyclable Electrodes December 13th, 2014

A golden thread through the labyrinth of nanomaterials December 12th, 2014

Announcements

Switching to spintronics: Berkeley Lab reports on electric field switching of ferromagnetism at room temp December 17th, 2014

ORNL microscopy pencils patterns in polymers at the nanoscale December 17th, 2014

Unraveling the light of fireflies December 17th, 2014

First Home-Made Edible Herbal Nanodrug Presented to Pharmacies across Iran December 17th, 2014

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







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE