Related Experiment Video
Updated: Aug 19, 2026

Preparation and Friction Force Microscopy Measurements of Immiscible, Opposing Polymer Brushes
Published on: December 24, 2014
Simple microscopic theory of Amontons's laws for static friction
M H Müser1, L Wenning, M O Robbins
1Institut fur Physik. WA 331, Johannes Gutenberg Universitat, 55099 Mainz, Germany.
Abstract:
A microscopic theory for the ubiquitous phenomenon of static friction is presented. Interactions between two surfaces are modeled by an energy penalty that increases exponentially with the degree of surface overlap. The resulting static friction is proportional to load, in accordance with Amontons's laws. However, the friction coefficient between bare surfaces vanishes as the area of individual contacts grows, except in the rare case of commensurate surfaces. An area independent friction coefficient is obtained for any surface geometry when an adsorbed layer of mobile atoms is introduced between the surfaces. The predictions from our simple analytic model are confirmed by detailed molecular dynamics simulations.
More Related Videos
Related Concept Videos
First Law: Particles in One-dimensional Equilibrium
Static and Kinetic Frictional Force
However, if two systems are in contact and are stationary relative to one...
Static Friction
For example, consider a scenario where a truck is connected to a car by a rope, ready to tow it along a road. When no external force is applied by the truck, the car remains stationary and is said to be in static equilibrium. In this case, the forces acting on the car, such as gravity and the...
Kinetic Friction
Characteristics of Dry Friction
Before the wheelbarrow starts moving, the static frictional force acts tangentially to the contact surface, opposing the force that is about to induce the motion. This frictional force prevents the...
Types of Friction Problems
The first type of dry friction problem involves situations where there is no apparent impending motion.

