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

Imaging electric charge propagating along microbial nanowires October 20th, 2014

Design of micro and nanoparticles to improve treatments for Alzheimers and Parkinsons: At the Faculty of Pharmacy of the UPV/EHU-University of the Basque Country encapsulation techniques are being developed to deliver correctly and effectively certain drugs October 20th, 2014

Physicists build reversible laser tractor beam October 20th, 2014

Removal of Limitations of Composites at Superheat Temperatures October 20th, 2014

Chip Technology

Crystallizing the DNA nanotechnology dream: Scientists have designed the first large DNA crystals with precisely prescribed depths and complex 3D features, which could create revolutionary nanodevices October 20th, 2014

Imaging electric charge propagating along microbial nanowires October 20th, 2014

Superconducting circuits, simplified: New circuit design could unlock the power of experimental superconducting computer chips October 18th, 2014

3DXNano™ ESD Carbon Nanotube 3D Printing Filament - optimized for demanding 3D printing applications in the semi-con and electronics industry October 16th, 2014

Sensors

Imaging electric charge propagating along microbial nanowires October 20th, 2014

Graphenea opens US branch October 16th, 2014

IRLYNX and CEA-Leti to Streamline New CMOS-based Infrared Sensing Modules Dedicated to Human-activities Characterization October 15th, 2014

Nanodevices for clinical diagnostic with potential for the international market: The development is based on optical principles and provides precision and allows saving vital time for the patient October 15th, 2014

Discoveries

Imaging electric charge propagating along microbial nanowires October 20th, 2014

Design of micro and nanoparticles to improve treatments for Alzheimers and Parkinsons: At the Faculty of Pharmacy of the UPV/EHU-University of the Basque Country encapsulation techniques are being developed to deliver correctly and effectively certain drugs October 20th, 2014

Physicists build reversible laser tractor beam October 20th, 2014

Removal of Limitations of Composites at Superheat Temperatures October 20th, 2014

Materials/Metamaterials

Removal of Limitations of Composites at Superheat Temperatures October 20th, 2014

Nanotechnology Improves Quality of Anti-Corrosive Coatings October 17th, 2014

Graphenea opens US branch October 16th, 2014

3DXNano™ ESD Carbon Nanotube 3D Printing Filament - optimized for demanding 3D printing applications in the semi-con and electronics industry October 16th, 2014

Announcements

Imaging electric charge propagating along microbial nanowires October 20th, 2014

Design of micro and nanoparticles to improve treatments for Alzheimers and Parkinsons: At the Faculty of Pharmacy of the UPV/EHU-University of the Basque Country encapsulation techniques are being developed to deliver correctly and effectively certain drugs October 20th, 2014

Physicists build reversible laser tractor beam October 20th, 2014

Removal of Limitations of Composites at Superheat Temperatures October 20th, 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