Micelle like structure

Some surfactants aggregate at the solid-liquid interface to form micelle-like structures, which are popularly known as hemimicelles or in general solloids (surface colloids) [23-26]. There is evidence in favor of the formation of these two-dimensional surfactant aggregates of ionic surfactants at the alumina-water surface and that of nonionic surfactants at the silica-water interface [23-26]. 

The dependence of Kss on sorbed SDS levels appears to be qualitatively consistent with proposed surfactant structures at mineral surfaces (Fuerstenau and Wakamatsu, 1975 Holsen et al., 1991 Chandar et al., 1987). For example, the configuration of adsorbed SDS in Region I is expected to be different from that in Regions II and III, where micelle-like structures are thought to exist at these relatively higher sorption densities. Apparently, these differences in sorbed surfactant structure that result from regional sorption mechanisms and sorption densities lead to regional differences in Kss values. 

Long, extremely well-organized nanorods are formed in aqueous solution of the amphiphilic ZnPc-Cgo salt 24 (Fig. 18a) [84], TEM images showed that the nanotubules are composed of many other nanorod-like substructures (Fig. 18b). These 1-D, Pc-based micelle-like structures display remarkable photophysical properties as a result of their nanometric organization, namely, an impressive stabilization of the charge separated state (ZnPc+-C6o ) lifetime. 

At relatively high concentrations (>20%), poloxa-mers form thermoreversible gels however, they gel on heating rather than cooling The amphiphilic nature supports the gelling mechanism of poloxamers, where micelle-like junction zones form at or above room temperature. The junction zones consist of large populations of micelle-like structures, which apparently form a viscous, liquid crystalline phase. Poloxamers can also form gels in dilute hydroalcoholic solutions. 

Hydrophobically modified polymers can associate in aqueous media to form micelle-like structures above their critical association concentrations (CACs). The nanosized self-aggregates were prepared using modified natural polysaccharides such as pullulan, curdlan, and glycol chitosan. The modified polysaccharides provide excellent biocompatibility, biodegradability, low immunogenicity, and biological activities. 

Rykke M, Smistadt G, Ralla G, Karlsen J Micelle-like structures in human saliva. Colloids Surf B Biointerfaces 1995 4 33 40. 

The two-stage growth process of the pellicle is of importance to the structure and function of the pellicle. The first step has been explained by an initial adsorption of discrete proteins to the enamel surface, whereas the second step is the adsorption of salivary protein aggregates in the form of micelle-like structures that move more slowly towards the interfaces, and hence give a stepwise increase in the pellicle thickness [47]. The latter structures are believed to account for the globular surface morphology of acquired salivary pellicle. 

Since surfactant molecules can aggregate into micelle-like structures on a solid surface, the enthalpies of micellization in the bulk phase are also listed in this table. They will... 

Figure 18 Aggregates of amphipathic dendrons in 0.1% NaCl, each of these micelle-like structures being about 50 nm in diameter. Source From Ref. 100.

Thus, the results of MD simulations provide ultimate support for the core-corona [the core comprises domains (a) and (b), as revealed in MD simulations] model of the structural organization of IPECs based on the star-shaped PEs, which was suggested on the basis of experimental findings [80], Together, experimental results and MD simulations provide evidence for a compartmentalized micelle-like structure that results from a pronounced nonuniform distribution of chains of the linear PE within the volume occupied by a molecule of the star-shaped PE. 

Synthetic glycopolymers of various architectures have been prepared in recent years using the fast development of controlled polymerization techniques and the very efficient coupling reactions in polymer analogous approaches. Both, linear and globular polymer structures that have been obtained by synthesizing dendritic, starlike, or micelle-like structures or nanogels have received much attention. 

The saturation of the hydrodynamic radius beyond the extra DBSA concentration of 1 g/dL implies that there is an optimum radius of the micelle-like structure of PPy-DBSA, over which the structure becomes energetically unstable. The radius of the PPy-DBSA micelle-like structure increased with increased PPy-DBSA conductivity (Figure 8.23) [68]. PPy-DBSA is expected to have different conductivities depending on by the PPy chain length. As the chain length increases, the core volume of the PPy-DBSA micelle-like structure increases, thereby increasing the total volume of the micelle-like structure. 

If the PPy-DBSA micelle-like structure were constructed by the aggregation of the multiple PPy-DBSA molecules, the obtained autocorrelation functions should be fitted by Gaussian decays as the a regate of PANi does [72,73]. Therefore, it is expected that the micelle-like structure of PPy-DBSA is composed of a single chain of PPy-DBSA surrounded by many extra DBSA molecules. 

The micelle-like structure of PPy-DBSA exists only in weakly polar solvents with extra DBSA in which the polymer-solvent interactions are relatively weak. The hydrodynamic volume of PPy-DBSA in polar solvents was too small to obtain an autocorrelation function on the available relaxation time scale. This failure was not improved by the addition of extra DBSA to the polar solvents because the molecular interaction between PPy-DBSA and the extra DBSA was limited by the polar solvents. On the other hand, this failure implies that PPy-DBSA exists as an isolated chain in polar solvents. 

The UV-Vis-NIR spectra of a PPy-DBSA solution in chloroform changed little with increasing concentration of the extra DBSA (Figure 8.27), indicating that the increase of extra DBSA concentration had no influence upon the electronic structure of PPy-DBSA since extra DBSA restricts the position of PPy-DBSA at the core of the micelle-like structure [68]. Moreover, due to additional doping with extra DBSA at the core of the micelle-like structure, the PPy-DBSA chain requires more extended conformation, which is favorable for intrachain charge transport. 

Earlier the interrelation between the influence of MR concentration on nonspecific activity of lysoz5mie and the destabilizing effect of MR on its native conformation were established. It is shown, that activity and thermostability of lysozyme depend on the concentration of MR and the incubation time of their mixed solutions [2]. The MR ability to self-orga-nization in a solution with micelle like structure formation was established via methods of mixing microcalorimetry and dynamic light scattering [3]. 

Small-angle neutron and x-ray scatterings were combined with electrochemical measurements for PA-enriched polyisoprene copolymers in order to understand the differences in oxidation-reduction properties and charge storage in the copolymer as compared with the behavior of separate homopolymers [121]. Microphase separation to micelle-like structures with the polyacetylene component surrounded by a nonoxidizable polyisoprene occurs in a solution, in electrodeposited films, and in solvent-cast films and affects the electrochemistry and the netics of charge storage. Electrodeposition of the copolymers is a possible route of copolymer separation from the mixed homopolymer. 

STM image of bare Au(100)-(1 x 1) at -0.5 V. The fourfold square lattice of the Au(lOO) surface is clearly identified from the images, with periodicities close to the inter-atomic distance of the corresponding surface. The adsorption of BMI+ cations successively forms disordered and then ordered micelle-like structures at potentials negative of -0.7 V [42], The potential region where the adsorption of anions and cations are observed are just at the two sides of the potential of capacitance maxima in a differential capacitance curve for the system, providing an experimental basis to validate theoretical prediction that potential of zero charge (PZC) is located close to the maxima [45]. 

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