Detergents molecules

On reversed phase layers, in contrast, detergents yield dark blue zones on a pale background. Here it is the lipophilic part of the detergent molecule that is aligned with the surface RP chain and the dye is attracted to the anionic part of the molecule. Steroid derivatives can also be detected with aqueous solutions of dyes [91]. 

Having an affinity for water, such as the sulfonate component of a detergent molecule. 

FIGURE 16.43 When a magnet is pulled up from this viscous ferrofluid, the particles of iron(lll) oxide align themselves with the magnetic field. Because strong attractions exist between the particles and the detergent molecules in the oil, the liquid is pulled into the field along with the particles. 

Figure 15.12 Detergent molecules can be used to solubilize carbon nanotubes by adsorption onto the surface through hydrophobic interactions and create half-micelle structures with the hydrophilic head groups facing outward into the aqueous environment.

Suspend the SWNTs in 1 percent (w/w) CDI-activated Tween 20 solution in water using sonication and allow the detergent molecules to bind for 30 minutes at room temperature. 

A model analogous to the Hill model (for enzymatic reactions), which describes a more accurate dependence of the observed rate constants on surfactant concentration, was developed by Piszkiewicz. This model is applicable especially at low surfactant concentration and the data may be treated without reference to CMC. According to this model, a substrate (S) and n number of detergent molecules (D), aggregate to form critical micelle (D S), which may react to yield the product... 

At their critical micelle concentrations, surface active agents (such as sodium dodecyl sulfate, Triton X-100, lysolecithin, and bile salts) self-associate into spherical or rod-shaped structures. Because dilution to below the c.m.c. results in rapid disassembly or dissolution of these detergent micelles, micelles are in dynamic equilibrium with other dissolved detergent molecules in the bulk solution. 

MICELLAR CATALYSIS. Chemical reactions can be accelerated by concentrating reactants on a micelle surface or by creating a favorable interfacial electrostatic environment that increases reactivity. This phenomenon is generally referred to as micellar catalysis. As pointed out by Bunton, the term micellar catalysis is used loosely because enhancement of reactivity may actually result from a change in the equilibrium constant for a reversible reaction. Because catalysis is strictly viewed as an enhancement of rate without change in a reaction s thermodynamic parameters, one must exercise special care to distinguish between kinetic and equilibrium effects. This is particularly warranted when there is evidence of differential interactions of substrate and product with the micelle. Micelles composed of optically active detergent molecules can also display stereochemical action on substrates. ... 

Below CMC, the detergent molecules are present as single monomers. Above CMC, they are present as monomers, Cmono, in equilibrium with micelles, Cmice. The micelle with aggregation number, Nag, is formed from monomers ... 

The process begins with an air bubble inside the liquid phase. At the surface, the bubble detaches and moves up under gravity. The detergent molecule forms a bilayer in the bubble film. The water in between is the same as the bulk solution. This may be depicted as follows a surface layer of detergent is applied, a bubble forms with air and a layer of detergent, and the bubble at the surface forms a double layer of detergent with some water in between TLF varying from 10 pm to 100 pm). 

Outer monolayer of detergent molecule Some amount of water Inner monolayer of detergent molecule Air on outer layer... 

The orientation of the detergent molecule in TLF is such as that the polar group (OO) is pointing toward the water phase, and the apolar alkyl part (CCCCCCCCCC) is pointing toward the air, as... 

The film looks black-gray, and its thickness is around 50 A (5 nm), which is almost the size of the bilayer structure of the detergent (i.e., twice the length [ca. 25 A] of a typical detergent molecule). Actually, it is a remarkable fact that one can see two molecules thin structure. The rainbow colors are observed since the light is reflected by the varying thickness of the TLF of the bubble. 

In a similar approach, the telomerization of butadiene (1) with glycerol (3) was studied [7, 8]. Moreover, no additional solvent was necessary with this substrate. The corresponding monoether can be used as detergent or emulsifier while, after hydrogenation and sulfonation, the diether could be transformed to potential detergent molecule. 

Types of detergents n, non-ionic a, anionic c, cationic z, zwitterionic N, Aggregation number (average munber of detergent molecules per micelle)... 

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