New study challenges centuries-old Amontons' laws of friction

November 29, 2013
New study challenges centuries-old Amontons’ laws of friction

( —The frictional characteristics of nanotextured surfaces cannot be fully described by the framework of Amontons' laws of friction, according to new research from the University of Bristol, published in ACS Nano.

Nanostructured surfaces are increasingly used in modern miniaturised devices, where nanosized surface features with well-defined geometry and dimensions are incorporated for tailored functionality and properties. It is thus crucially important to understand frictional properties of such nanostructured surfaces.

In order to assess data obtained on nanostructured surfaces, scientists have hitherto resorted to the laws of friction described by French physicist Guillaume Amontons in 1699 – particularly the concept of friction coefficient (that is, the ratio between friction and applied load) devised for interpreting the phenomenological macroscopic frictional behaviour of rubbing surfaces.

From violin playing to earthquakes, stick-slip frictional behaviours are widespread in macroscopic phenomena. Using a nanosized AFM (atomic force microscope) tip to scan across a nanodomed , the Bristol researchers revealed sustained stick-slip frictional instabilities under all the velocity and load regimes studied. A linear dependence between the amplitude sf of these frictional oscillations and the applied load was found, leading to the definition of the slope as the stick-slip amplitude coefficient (SSAC).

The scientists thus propose that the frictional characteristics of nanotextured surfaces cannot be fully described by the framework of Amontons' laws of friction, and that additional parameters (for examples sf and SSAC) are required when their friction, lubrication and wear properties are important considerations in related nanodevices.

Explore further: New nano-measurements add spark to centuries-old theory of friction

More information: 'Sustained Frictional Instabilities on Nanodomed Surfaces: Stick–Slip Amplitude Coefficient' by Benoit Quignon, Georgia A. Pilkington, Esben Thormann, Per M. Claesson, Michael N. R. Ashfold, Davide Mattia, Hannah Leese, Sean A. Davis and Wuge H. Briscoe in ACS Nano:

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 ...

Graphite lubricates fault zones

May 7, 2013

Graphite is known to be a low-friction material, and rocks rich in graphite are often found in fault zones. Oohashi et al. conducted laboratory studies to determine how much graphite is needed to reduce the frictional strength ...

Physicists discover a new kind of friction in the nanoworld

May 15, 2013

Whether in vehicle transmissions, hip replacements, or tiny sensors for triggering airbags: The respective components must slide against each other with minimum friction to prevent loss of energy and material wear. Investigating ...

Controlling friction by tuning van der Waals forces

July 19, 2013

For a car to accelerate there has to be friction between the tire and the surface of the road. The amount of friction generated depends on numerous factors, including the minute intermolecular forces acting between the two ...

Recommended for you

Physicists develop new technique to fathom 'smart' materials

November 26, 2015

Physicists from the FOM Foundation and Leiden University have found a way to better understand the properties of manmade 'smart' materials. Their method reveals how stacked layers in such a material work together to bring ...

Mathematicians identify limits to heat flow at the nanoscale

November 24, 2015

How much heat can two bodies exchange without touching? For over a century, scientists have been able to answer this question for virtually any pair of objects in the macroscopic world, from the rate at which a campfire can ...

New sensor sends electronic signal when estrogen is detected

November 24, 2015

Estrogen is a tiny molecule, but it can have big effects on humans and other animals. Estrogen is one of the main hormones that regulates the female reproductive system - it can be monitored to track human fertility and is ...


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.