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Related Concept Videos

Surface Tension of Fluid01:22

Surface Tension of Fluid

Surface tension is a fundamental property of fluids, occurring at the boundary between a liquid and a gas or between two immiscible liquids. This phenomenon arises from the cohesive forces between molecules at the fluid's surface, creating an effect similar to a stretched elastic membrane. Inside each fluid, molecules are equally attracted in all directions by neighboring molecules, but surface molecules experience a net inward force, resulting in surface tension.
Surface tension varies with...
Surface Tension, Capillary Action, and Viscosity02:57

Surface Tension, Capillary Action, and Viscosity

Surface Tension
The various IMFs between identical molecules of a substance are examples of cohesive forces. The molecules within a liquid are surrounded by other molecules and are attracted equally in all directions by the cohesive forces within the liquid. However, the molecules on the surface of a liquid are attracted only by about one-half as many molecules. Because of the unbalanced molecular attractions on the surface molecules, liquids contract to form a shape that minimizes the number...
Characteristics of Dry Friction01:21

Characteristics of Dry Friction

Dry friction occurs when two solid surfaces slide against each other without any lubrication or fluid present. It causes resistance when pushing objects along a surface, like a gardener pushing a wheelbarrow. The force applied to move the cart causes dry friction between the wheel and the ground.
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Frictional Force01:07

Frictional Force

When a body is in motion, it encounters resistance because the body interacts with its surroundings. This resistance is known as friction, a common yet complex force whose behavior is still not completely understood. Friction opposes relative motion between systems in contact, but also allows us to move. Friction arises in part due to the roughness of surfaces in contact. For one object to move along a surface, it must rise to where the peaks of the surface can skip along the bottom of the...
Dry Friction01:30

Dry Friction

Dry friction occurs between two solid surfaces in contact as they attempt to move relative to one another. In daily life, dry friction is encountered in various forms, such as when walking on the ground, sliding an object across a table, or rubbing hands together. Despite its ubiquity, the underlying mechanisms behind dry friction are not readily visible.
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Surface Tension01:24

Surface Tension

Surface tension is defined as the force per unit length (γ) acting along the surface of a liquid. It arises due to strong intermolecular forces of attraction. A molecule located inside the bulk of the liquid is surrounded by other molecules and experiences equal forces in all directions. However, a molecule at the surface experiences unbalanced forces because there are more neighboring molecules below than above. This creates a net inward force that pulls surface molecules toward the interior,...

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Glass-Based Devices to Generate Drops and Emulsions
08:45

Glass-Based Devices to Generate Drops and Emulsions

Published on: April 5, 2022

Friction-formed liquid droplets.

A J Lockwood1, K Anantheshwara, M S Bobji

  • 1NanoLAB Centre, Department of Materials Science and Engineering, University of Sheffield, Sheffield S1 3JD, UK. a.lockwood@sheffield.ac.uk

Nanotechnology
|February 4, 2011
PubMed
Summary
This summary is machine-generated.

Scientists observed nanoscale liquid droplets forming during solid friction using in situ transmission electron microscopy (TEM). This reveals dynamic solid-liquid interactions and phase separation during wear, impacting nanotribology.

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Area of Science:

  • Materials Science
  • Nanotechnology
  • Tribology

Background:

  • Friction and wear at the nanoscale are critical for material performance.
  • Understanding dynamic processes during wear is essential for developing advanced materials.
  • Previous studies lacked real-time observation of nanoscale wear particle evolution.

Purpose of the Study:

  • To observe and characterize the real-time formation of nanoscale liquid droplets during solid friction.
  • To investigate the phase separation and nanomechanics of wear debris.
  • To explore the role of liquid nanodroplets in nanotribological processes.

Main Methods:

  • Development of a novel in situ transmission electron microscope (TEM) triboprobe.
  • Application of reciprocating wear cycles to a focused-ion-beam (FIB) processed Al alloy against diamond.
  • Real-time dynamical imaging of nanoscale friction and wear events.

Main Results:

  • Observed real-time formation of nanoscale liquid droplets from wear particles.
  • Identified phase separation into liquid gallium nanodroplets and liquid bridges.
  • Demonstrated the significant alteration of friction and wear dynamics by the solid-liquid system.
  • Observed liquid bridges interacting with nanoparticle debris and asymmetric menisci due to surface roughness.

Conclusions:

  • Nanoscale liquid droplet formation and phase separation are key phenomena during solid friction.
  • In situ TEM nanotribology provides unprecedented insights into dynamic solid-liquid nanomechanics.
  • This research opens new avenues for understanding and controlling friction and wear in nanosystems.