Evolution mechanism micelles

Examples. 2D SAXS/WAXS experiments on highly anisotropic polymer materials during melting and crystallization can be used to visualize and understand the evolution of nanostructure [56,57], Transformations of biopolymers in solution, e.g., virus crystallization can be studied in situ [58], It is possible to study solidification mechanisms of spider silk [59], or the self-assembly of micelles on a time-scale of milliseconds [60],... 

What is missing in this scheme are two elements which are essential for a molecular Darwinist approach to the origin of life, namely evolution of the replicators and their competition to produce the survival of the best fit. We have shown here that in principle it is possible to implement these mechanisms with vesicles. It is now needed to show that this is indeed the case. This is one fruitful direction for the work in the field of supramolecular surfactant aggregates, so as to give a dynamic aspect to the chemistry of micelles and vesicles. 

As explained before, when surfactant, water, and monomer(s) are mixed, the colloidal system obtained consists of monomer-swollen micelles (if the surfactant concentration exceeds its CMC) and monomer droplets dispersed in an aqueous phase that contains dissolved molecules of surfactant and a small amount of the sparingly water-soluble monomer(s). When free radicals are generated in the aqueous phase by action of an initiator system, then the emulsion polymerization takes place. Its evolution is such that the colloidal entities initially present tend to disappear and new colloidal entities (polymer latex particles) are bom by a process called nucleation. For convenience, we first focus on the particle nucleation mechanisms, a very important aspect of emulsion polymerization. 

When a water-soluble initiator is added to a microemul-sion, polymer particles are nucleated mainly by the micellar mechanism. The role of the monomer-swollen micelles in microemulsion polymerization is not only to act as nucle-ation loci and surfactant reservoir but also as monomer reservoir. The fast nucleation rate leads to the initial increment of Rp. As the monomer is polymerized, its concentration in micelles diminishes and eventually monomer concentration within polymer particles decreases as well [205]. As a consequence, the nucleation and polymerization rates tend to decrease, explaining in this way the maximum in the Rp evolution curve experimentally observed. The final latex consists of surfactant-stabilized polymer particles that typically contain only polymer and empty micelles formed by excess surfactant. 

In Fig. 16, experimental results of the time-dependent intensity after mixing proteated and deuterated PS-PB micelles in DMF under KZAC conditions [101] are shown. As can be seen the intensity decreases with time, directly showing that the micelles mix and kinetic processes are active. By analyzing the evolution of the scattered intensity and appropriate modeling, the mechanism and pathways can be determined from these experiments. In the following section, the technicalities will be described in more detail. 

Figure 11.12 shows the proposed scheme for the stractural evolution during the synthesis, based in a liquid-crystal templating (LCT) mechanism. Initially, the aqueous acid solution is solubihzed in the cyhndrical reverse micelles forming the reverse hexagonal phase. Nonhydrolyzed TEOS molecules and PDMS chains are mutually soluble and therefore constitute the hydrophobic continuous medium. The hydrolysis is probably driven by interfacial diffusion of the water towards the... 

In the last years large attention was devoted to the synthesis and characterization of SBA-16 material focusing the interest on the formation mechanisms of copolymer micelles which drive the organization of the final siliceous mesostructure. In this framework, the physico-chemical properties at the interface between silica and triblock E0106P070E0106 co-polymer in a SBA-16 material were investigated. In particular, the combination of IR spectroscopy with SS NMR allowed to obtain complementary information on how the surfactant co-polymer interacts with the SBA-16 surface silanols in the presence or absence of physisorbed water and to follow the evolution of the structural organization of the co-polymer, which depends on the hydration degree of the SBA-16 sample. 

In this paper, the results of a Monte Carlo method for the simulation of the stochastic time evolution of the micellization process are presented. The computational algorithm [1] used represents an optimization of a general procedure introduced by Gillespie some years ago [2]. It was applied to the case of surfactant reversible association according to the general mechanism reported in Fig. 1 that allows associations and dissociations among -mers of whatever aggregation number. 

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