Researchers tune friction in ionic solids at the nanoscale

January 27, 2015
ORNL researchers tune friction in ionic solids at the nanoscale
Researchers used electricity and water to control friction levels on ionic surfaces at the nanoscale. As water forms around the nanoscale electrode, it allows for further penetration into the sample surface, thereby increasing or decreasing friction. Credit: ORNL

Friction impacts motion, hence the need to control friction forces. Currently, this is accomplished by mechanistic means or lubrication, but experiments conducted by researchers at the Department of Energy's Oak Ridge National Laboratory have uncovered a way of controlling friction on ionic surfaces at the nanoscale using electrical stimulation and ambient water vapor.

The research, which demonstrates a new physical effect, was undertaken at the Center for Nanophase Materials Sciences, a DOE Office of Science User Facility at ORNL, and is published in the journal Scientific Reports.

"Our finding can have a significant technological impact on applications for both macroscopic and ," said lead author Evgheni Strelcov. "Decreasing or increasing at will and thus controlling mechanical energy losses and wear of a microelectromechanical system's parts has enormous implications for applied energy research and opens a new vista for fundamental science studies."

By inducing a strong electric field using an atomic force microscope, the researchers were able to both increase and decrease friction between a moving nanoscale electrode and an ionic surface. They argue that the primary effect responsible for this behavior is condensation of moisture from the surrounding air into liquid that can then reduce friction.

Simultaneously, further strengthening the results in the nanoscale electrode penetrating the surface and an increase of friction. This penetration is a new and unexpected effect, and the overall approach differs from other methods of friction control that often require adding a lubricant to the system instead of drawing on resources readily available in the immediate environment.

Additionally, unlike other electrochemical friction control practices, the new technique does not require an electrical current, which is associated with energy losses.

"Absence of current is highly beneficial from a power-saving perspective as it eliminates Joule heating and other parasitic power-consuming effects," says Bobby Sumpter, who led the group developing associated theoretical models.

This work builds on extensive efforts at CNMS exploring the electrical manipulation of mechanical, electrochemical and ferroelectric properties of materials.

"We adopted this biased view on the nanoscale almost a decade ago," said contributing author Sergei Kalinin. "Now we can proceed from observation to control of even such sublime phenomena as , and it is indeed very surprising and promising that we can both increase and decrease it."

Explore further: Finnish researchers find explanation for sliding friction

More information: The paper can be accessed at: www.nature.com/srep/2015/150127/srep08049/full/srep08049.html

Related Stories

Finnish researchers find explanation for sliding friction

May 29, 2012

Friction is a key phenomenon in applied physics, whose origin has been studied for centuries. Until now, it has been understood that mechanical wear-resistance and fluid lubrication affect friction, but the fundamental origin ...

Recommended for you

Nanoscale view of energy storage

January 16, 2017

In a lab 18 feet below the Engineering Quad of Stanford University, researchers in the Dionne lab camped out with one of the most advanced microscopes in the world to capture an unimaginably small reaction.

Scientists create first 2-D electride

January 11, 2017

(Phys.org)—Researchers have brought electrides into the nanoregime by synthesizing the first 2D electride material. Electrides are ionic compounds, which are made of negative and positive ions. But in electrides, the negative ...

Semiconductor eyed for next-generation 'power electronics'

January 10, 2017

Researchers have demonstrated the high-performance potential of an experimental transistor made of a semiconductor called beta gallium oxide, which could bring new ultra-efficient switches for applications such as the power ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.