Brush Contact
Brush Contact - Related Videos
13:57
Preparation and Friction Force Microscopy Measurements of Immiscible, Opposing Polymer Brushes
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Cited by 4 •
2014
The methodology to perform friction force microscopy experiments for contacting brushes is presented: Two polymer brushes that are grafted from (a) substrates and (b) colloidal probes are slid to show that, by using two contacting immiscible brush systems, friction in sliding contacts is reduced compared to miscible brush systems.
06:56
Particles without a Box: Brush-first Synthesis of Photodegradable PEG Star Polymers under Ambient Conditions
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Cited by 17 •
2013
Poly(ethylene glycol) (PEG) brush-arm star polymers (BASPs) with narrow mass distributions and tunable nanoscopic sizes are synthesized in via ring opening metathesis polymerization (ROMP) of a PEG-norbornene macromonomer followed by transfer of portions of the resulting living brush initiator to vials containing varied amounts of a rigid, photo-cleavable bis-norbornene crosslinker.
01:13
Contact Angle
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2023
When a solid is dipped inside a liquid, the liquid surface becomes curved near the contact. For some solid–liquid interfaces, the liquid is pulled up along the solid, while for others, the liquid surface is convex or depressed near the solid surface. This phenomenon can be explained using the concept of cohesive and adhesive forces. The adhesive force is the molecular force between molecules of different materials, that is, between the molecules of the solid and the liquid. The cohesive force...
08:25
Contact Hypersensitivity as a Murine Model of Allergic Contact Dermatitis
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Cited by 2 •
2022
Contact hypersensitivity (CHS) is a murine experimental model of allergic contact dermatitis (ACD). CHS is based on sensitization with reactive hapten by painting the shaved skin of the chest and abdomen, with a subsequent ear skin challenge with a diluted hapten, causing a swelling reaction that is assessed in various ways.
03:55
Larval Contact Assay: A Procedure to Evaluate Mosquito Larval Mortality following Direct Contact with Test Larvicidal Compound
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2025
In this video, we describe the larval contact assay to evaluate the toxicity of the dopamine receptor antagonist amitriptyline on the third instar stage larvae of mosquitoes, known vectors of several human infectious diseases. Assessing the larval mortality upon incubation with different amitriptyline concentrations over different time intervals helps determine its lethal concentration 50.
FAQs
Contact pressure determines how firmly the conductive brush meets the rotating surface, while surface condition affects the number and quality of microscopic current-carrying points. Too little effective contact can increase electrical resistance, and changes at the sliding interface can alter friction and wear. These variables therefore influence efficiency, maintenance needs, and service life.
Sliding creates friction at the brush interface, and that friction contributes to gradual material wear. At the same time, microscopic contact points produce electrical resistance, which can contribute to heat generation as current passes through the connection. The combined effects can reduce efficiency and shorten component lifespan, making the contact surface and brush material important performance factors.
Current density describes how much current passes through a given area of the contact interface. Higher concentration of current at microscopic points can increase local electrical stress and heat generation, while the resulting thermal and mechanical effects may accelerate wear. Evaluating current density helps explain changes in efficiency, reliability, and operating life.
Design evaluation should include brush material, contact pressure, surface condition, expected current density, friction, wear, and heat generation. Carbon or carbon-based composites are identified as common brush materials, but their performance depends on the complete sliding interface rather than material choice alone. Considering these variables together helps balance current transfer, efficiency, maintenance, and lifespan.
In brushed motors and generators, the contact maintains electrical continuity while one component rotates relative to another. Current transfer allows the electromechanical system to operate despite continuous sliding at the interface. Performance depends on controlling resistance, friction, wear, pressure, and heat, because these factors affect efficiency and the maintenance requirements of the machine.
Condition becomes important whenever a rotating measurement system must maintain current transfer over continued sliding operation. Changes in contact pressure, surface condition, resistance, or wear can influence the quality and reliability of the electrical connection. Monitoring these factors helps assess whether the system can continue operating efficiently and whether maintenance may be needed.