Nanotechnology Now

Our NanoNews Digest Sponsors
Heifer International



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

Virginia Tech physicists propose path to faster, more flexible robots: Virginia Tech physicists revealed a microscopic phenomenon that could greatly improve the performance of soft devices, such as agile flexible robots or microscopic capsules for drug delivery May 17th, 2024

Gene therapy relieves back pain, repairs damaged disc in mice: Study suggests nanocarriers loaded with DNA could replace opioids May 17th, 2024

Shedding light on perovskite hydrides using a new deposition technique: Researchers develop a methodology to grow single-crystal perovskite hydrides, enabling accurate hydride conductivity measurements May 17th, 2024

Oscillating paramagnetic Meissner effect and Berezinskii-Kosterlitz-Thouless transition in cuprate superconductor May 17th, 2024

Chip Technology

Diamond glitter: A play of colors with artificial DNA crystals May 17th, 2024

Oscillating paramagnetic Meissner effect and Berezinskii-Kosterlitz-Thouless transition in cuprate superconductor May 17th, 2024

Discovery points path to flash-like memory for storing qubits: Rice find could hasten development of nonvolatile quantum memory April 5th, 2024

Utilizing palladium for addressing contact issues of buried oxide thin film transistors April 5th, 2024

Sensors

Innovative sensing platform unlocks ultrahigh sensitivity in conventional sensors: Lan Yang and her team have developed new plug-and-play hardware to dramatically enhance the sensitivity of optical sensors April 5th, 2024

$900,000 awarded to optimize graphene energy harvesting devices: The WoodNext Foundation's commitment to U of A physicist Paul Thibado will be used to develop sensor systems compatible with six different power sources January 12th, 2024

A color-based sensor to emulate skin's sensitivity: In a step toward more autonomous soft robots and wearable technologies, EPFL researchers have created a device that uses color to simultaneously sense multiple mechanical and temperature stimuli December 8th, 2023

New tools will help study quantum chemistry aboard the International Space Station: Rochester Professor Nicholas Bigelow helped develop experiments conducted at NASA’s Cold Atom Lab to probe the fundamental nature of the world around us November 17th, 2023

Discoveries

Virginia Tech physicists propose path to faster, more flexible robots: Virginia Tech physicists revealed a microscopic phenomenon that could greatly improve the performance of soft devices, such as agile flexible robots or microscopic capsules for drug delivery May 17th, 2024

Diamond glitter: A play of colors with artificial DNA crystals May 17th, 2024

Finding quantum order in chaos May 17th, 2024

Advances in priming B cell immunity against HIV pave the way to future HIV vaccines, shows quartet of new studies May 17th, 2024

Materials/Metamaterials/Magnetoresistance

How surface roughness influences the adhesion of soft materials: Research team discovers universal mechanism that leads to adhesion hysteresis in soft materials March 8th, 2024

Nanoscale CL thermometry with lanthanide-doped heavy-metal oxide in TEM March 8th, 2024

Focused ion beam technology: A single tool for a wide range of applications January 12th, 2024

Catalytic combo converts CO2 to solid carbon nanofibers: Tandem electrocatalytic-thermocatalytic conversion could help offset emissions of potent greenhouse gas by locking carbon away in a useful material January 12th, 2024

Announcements

Virginia Tech physicists propose path to faster, more flexible robots: Virginia Tech physicists revealed a microscopic phenomenon that could greatly improve the performance of soft devices, such as agile flexible robots or microscopic capsules for drug delivery May 17th, 2024

Diamond glitter: A play of colors with artificial DNA crystals May 17th, 2024

Finding quantum order in chaos May 17th, 2024

Oscillating paramagnetic Meissner effect and Berezinskii-Kosterlitz-Thouless transition in cuprate superconductor May 17th, 2024

NanoNews-Digest
The latest news from around the world, FREE




  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project