Cationic Surfactants
Cationic Surfactants - Related Videos
09:34
Extraction and Characterization of Surfactants from Atmospheric Aerosols
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Cited by 26 •
2017
Methods are presented for the targeted extraction of surfactants present in atmospheric aerosols and the determination of their absolute concentrations and surface tension curves in water, including their Critical Micelle Concentration (CMC).
10:28
Experimental Measurement of Settling Velocity of Spherical Particles in Unconfined and Confined Surfactant-based Shear Thinning Viscoelastic Fluids
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Cited by 15 •
2014
This paper demonstrates the experimental procedure to measure terminal settling velocities of spherical particles in surfactant-based shear thinning viscoelastic fluids. Fluids over a wide range of rheological properties are prepared and settling velocities are measured for a range of particle sizes in unbounded fluids and fluids between parallel walls.
10:23
Synthesis of Cationized Magnetoferritin for Ultra-fast Magnetization of Cells
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Cited by 1 •
2016
A protocol for the synthesis and cationization of cobalt-doped magnetoferritin is presented, as well as a method to rapidly magnetize stem cells with cationized magnetoferritin.
07:20
Lavage-induced Surfactant Depletion in Pigs As a Model of the Acute Respiratory Distress Syndrome (ARDS)
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Cited by 21 •
2016
Repeated pulmonary lavages in anesthetized pigs induce lung injury resembling major aspects of human acute respiratory distress syndrome (ARDS). For this purpose the lungs are repeatedly lavaged with 0.9% saline at 37 °C. The goal of the protocol is a reproducible mitigation of gas exchange and hemodynamics for research in ARDS.
01:19
Assessing Bacterial Biofilm Formation Using a Cationic Dye-Based Assay
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2026
Begin with a bacterial suspension in nutrient media.Add the suspension to a multi-well plate and incubate.The nutrients in the media facilitate bacterial growth and attachment.The adhered bacteria secrete extracellular polymeric substances consisting of polysaccharides, proteins, and DNA to form a layer of biofilm.Wash multiple times with buffer to remove unbound bacteria.Invert the plate to ensure the removal of residual liquid from the well and allow the biofilm to dry.Treat with a fixative...
FAQs
The critical micelle concentration (CMC) marks a change in how cationic surfactants organize in water. Below this concentration, individual molecules can associate through their hydrocarbon tails while their charged heads remain oriented toward the solvent. Above it, additional molecules preferentially contribute to micelles. This threshold helps relate concentration to self-assembly and interfacial behavior.
Electrostatic attraction between the positively charged head groups and negatively charged surfaces drives strong adsorption. Once the head groups associate with a surface, the hydrophobic tails remain part of the organized interfacial layer. This charge-dependent interaction is important for understanding how these compounds modify solid-liquid interfaces and contribute to colloidal behavior.
The charged head group interacts with the surrounding solvent and determines how the molecule responds to nearby charged interfaces. Its positive charge also influences association with negatively charged surfaces, while the nonpolar tail favors interactions with other tails. The combination allows one molecule to participate in both solvent-facing and interface-associated arrangements.
Cationic surfactants can accumulate at interfaces and modify interactions between dispersed materials and the surrounding liquid. Their amphiphilic structure allows hydrophobic regions to associate with nonpolar components while charged heads interact with the solvent. These interfacial effects support their use in emulsions and dispersions, where controlling organization and colloidal stability is important.
Strong adsorption onto negatively charged surfaces helps explain the use of cationic surfactants in fabric softeners. Their positively charged head groups can associate with negatively charged material surfaces, while the hydrophobic portions remain organized away from the surface. This application illustrates how charge-dependent molecular interactions translate into a practical surface-treatment function.
In chemistry, these compounds provide a system for examining self-assembly, interfacial phenomena, colloidal stability, and charge-dependent molecular interactions. Researchers can connect molecular organization, micelle formation above the critical micelle concentration, and adsorption onto negatively charged surfaces with broader behavior at liquid, solid, and gas interfaces. They are also relevant to antimicrobial formulations.