The Effects of Single- and Twin-Tailed Ionic Surfactants on the Hydroxydehalogenation of Charged Substrates

1991 ◽  
Vol 44 (10) ◽  
pp. 1505
Author(s):  
A Cipiciani ◽  
S Primieri
Keyword(s):  
Colloidal Particles ◽  
Ionic Surfactants ◽  
Cetyltrimethylammonium Chloride ◽  
Micellar Aggregates ◽  
Rate Effects ◽  
Dimethylammonium Chloride

Reactions of OH- with 4-chloro-3,5-dinitrobenzoic and 2-chloro-3,5-dinitrobenzoic acids have been examined in solutions of cetyltrimethylammonium chloride, bromide and hydroxide, bis ( dodecyl ) dimethylammonium chloride, and bis(tetradecyl) dimethylammonium chloride. Rate effects were analysed quantitatively in terms of the distribution of reactants between water and the colloidal particles. It has been found that twin-tailed ionic surfactants better distinguish between favourable and unfavourable orientations of substrate molecules within micellar aggregates than do single-tailed ionic surfactants.

Nitroso Group Transfer Reactions between N-Methyl-N-Nitroso-P-Toluene Sulfonamide and N-Alkylamines in CTACL Micellar Aggregates

2006 ◽  
Vol 31 (3) ◽  
pp. 129-138 ◽  
Author(s):  
L. García-Río ◽  
J.C. Mejuto ◽  
M. Pérez-Lorenzo ◽  
P. Rodríguez-Dafonte
Keyword(s):  
Binding Constant ◽  
Transfer Reactions ◽  
Micellar Media ◽  
Cetyltrimethylammonium Chloride ◽  
Nitroso Group ◽  
Micellar Phase ◽  
Group Transfer ◽  
Pseudophase Model ◽  
Micellar Aggregates ◽  
Intrinsic Reactivity

The influence of micellar media upon the transnitrosation reaction between N-methyl-N-nitroso-p-toluensulfonamide (MNTS) and three linear alkylamines (n-octylamine (OA), N-methyl-n-octylamine (MOA) and N,N-dimethyl-n-octylamine (DMOA)) in micelles of Cetyltrimethylammonium Chloride (CTACl) has been studied. The rate constants were obtained and the pseudophase model allowed us to obtain the intrinsic reactivity constants in the aqueous pseudophase and in the micellar pseudophase (ki2 and kw2) and the binding constant of the amines to the micellar phase (Ka).

scholarly journals Light-induced manipulation of passive and active microparticles

2021 ◽  
Vol 44 (4) ◽  
Author(s):  
Pooja Arya ◽  
Maren Umlandt ◽  
Joachim Jelken ◽  
David Feldmann ◽  
Nino Lomadze ◽  
...  
Keyword(s):  
Steady State ◽  
Colloidal Particles ◽  
Solid Wall ◽  
Ionic Surfactants ◽  
Concentration Gradients ◽  
Profile Shape ◽  
Osmotic Flow ◽  
Flow Generation ◽  
Controlled Flow ◽  
Shape And Size

Abstract We consider sedimented at a solid wall particles that are immersed in water containing small additives of photosensitive ionic surfactants. It is shown that illumination with an appropriate wavelength, a beam intensity profile, shape and size could lead to a variety of dynamic, both unsteady and steady state, configurations of particles. These dynamic, well-controlled and switchable particle patterns at the wall are due to an emerging diffusio-osmotic flow that takes its origin in the adjacent to the wall electrostatic diffuse layer, where the concentration gradients of surfactant are induced by light. The conventional nonporous particles are passive and can move only with already generated flow. However, porous colloids actively participate themselves in the flow generation mechanism at the wall, which also sets their interactions that can be very long ranged. This light-induced diffusio-osmosis opens novel avenues to manipulate colloidal particles and assemble them to various patterns. We show in particular how to create and split optically the confined regions of particles of tunable size and shape, where well-controlled flow-induced forces on the colloids could result in their crystalline packing, formation of dilute lattices of well-separated particles, and other states. Graphic Abstract

Diffusiophoresis in ionic surfactants: effect of micelle formation

Soft Matter ◽  
2019 ◽  
Vol 15 (2) ◽  
pp. 278-288 ◽  
Author(s):  
Patrick B. Warren ◽  
Sangwoo Shin ◽  
Howard A. Stone
Keyword(s):  
Self Assembly ◽  
Surfactant Concentration ◽  
Colloidal Particles ◽  
Micelle Formation ◽  
Ionic Surfactants ◽  
Ionic Surfactant ◽  
Association Model ◽  
Concentration Gradients ◽  
Chemical Association

We explore the consequences of micelle formation for diffusiophoresis of charged colloidal particles in ionic surfactant concentration gradients, using a quasi-chemical association model for surfactant self assembly.

Cryo-TEM of CTAB micelles and microemulsions

1988 ◽  
Vol 46 ◽  
pp. 112-113
Author(s):  
Phillip K. Vinson
Keyword(s):  
Mean Curvature ◽  
Surfactant Concentration ◽  
Phase Region ◽  
Water Soluble ◽  
Ionic Surfactants ◽  
Electrostatic Repulsion ◽  
Micellar Aggregates ◽  
Head Groups ◽  
Cylindrical Micelles ◽  
Spherical Micelles

Single-tailed surfactant molecules in aqueous solutions can associate into several different microstructural forms within a one-phase region of the phase diagram (Fig. 1). The molecules associate into globular aggregates called spherical micelles above a surfactant concentration called the critical micelle concentration, or cmc. At higher surfactant concentrations some surfactants will associate into rod-like micelles called cylindrical micelles. In systems containing ionic surfactants the transition from spherical to cylindrical micelles can be brought about at lower surfactant concentrations by adding an electrolyte. The electrolyte screens the electrostatic repulsion between surfactant head groups and allows formation of the lower mean curvature cylindrical microstructures. Micellar aggregates are equilibrium microstructures in which the nonpolar (often hydrocarbon or fluorocarbon) moieties of the surfactant molecules are shielded from the aqueous medium by the water-soluble moieties of the surfactant molecules. The solubilization of oil into the nonpolar micelle interior produces an aqueous solution of oil swollen micelles, i.e., a microemulsion.

Ultrastructure of Lymphatic Capillaries in the Transport of Colloidal Particles

1967 ◽  
Vol 25 ◽  
pp. 186-187
Author(s):  
L. V. Leak ◽  
J. F. Burke
Keyword(s):  
Connective Tissue ◽  
Colloidal Particles ◽  
Ultrastructural Level ◽  
Vital Role ◽  
Time Intervals ◽  
Thorium Dioxide ◽  
Lymphatic Capillary ◽  
Tissue Area ◽  
Rapid Removal ◽  
Tissue Fluids

The vital role played by the lymphatic capillaries in the transfer of tissue fluids and particulate materials from the connective tissue area can be demonstrated by the rapid removal of injected vital dyes into the tissue areas. In order to ascertain the mechanisms involved in the transfer of substances from the connective tissue area at the ultrastructural level, we have injected colloidal particles of varying sizes which range from 80 A up to 900-mμ. These colloidal particles (colloidal ferritin 80-100A, thorium dioxide 100-200 A, biological carbon 200-300 and latex spheres 900-mμ) are injected directly into the interstitial spaces of the connective tissue with glass micro-needles mounted in a modified Chambers micromanipulator. The progress of the particles from the interstitial space into the lymphatic capillary lumen is followed by observing tissues from animals (skin of the guinea pig ear) that were injected at various time intervals ranging from 5 minutes up to 6 months.

Deposited emulsion particles in the pores of aluminum oxide film

1978 ◽  
Vol 36 (1) ◽  
pp. 450-451
Author(s):  
Michio Ashida ◽  
Yasukiyo Ueda
Keyword(s):  
Oxide Film ◽  
Acid Solution ◽  
Barrier Layer ◽  
Colloidal Particles ◽  
Oxalic Acid Solution ◽  
Anodic Oxide ◽  
Anodic Oxide Film ◽  
Carbon Replica ◽  
Sectioning Method ◽  
Thin Sectioning

An anodic oxide film is formed on aluminum in an acidic elecrolyte during anodizing. The structure of the oxide film was observed directly by carbon replica method(l) and ultra-thin sectioning method(2). The oxide film consists of barrier layer and porous layer constructed with fine hexagonal cellular structure. The diameter of micro pores and the thickness of barrier layer depend on the applying voltage and electrolyte. Because the dimension of the pore corresponds to that of colloidal particles, many metals deposit in the pores. When the oxide film is treated as anode in emulsion of polyelectrolyte, the emulsion particles migrate onto the film and deposit on it. We investigated the behavior of the emulsion particles during electrodeposition.Aluminum foils (99.3%) were anodized in either 0.25M oxalic acid solution at 30°C or 3M sulfuric acid solution at 20°C. After washing with distilled water, the oxide films used as anode were coated with emulsion particles by applying voltage of 200V and then they were cured at 190°C for 30 minutes.

The reinforcing and rate effects of intracranial dopamine administration.

1986 ◽  
Author(s):  
Steven I. Dworkin ◽  
Nick E. Goeders ◽  
James E. Smith
Keyword(s):  
Rate Effects
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