Particle micelle

The emulsion polymerization system consists of three phases an aqueous phase (containing initiator, emulsifier, and some monomer), emulsified monomer droplets, the monomer-swollen micelles, and monomer-swollen particles. Water is the most important ingredient of the emulsion polymerization system. It is inert and acts as the locus of initiation (the formation of primary and oligomeric radicals) and the medium of transfer of monomer and emulsifier from monomer droplets or the monomer-swollen particle micelles to particles. An aqueous phase maintains a low viscosity and provides an efficient heat transfer. 

Depletion Interaction. When the distance between two plates is smaller than the diameter l of the small particles (micelles), which, in the present case, are uncharged, the depletion force /deP acting between two plates is given by7 20 21... 

As the oligomeric radical grows it becomes strongly hydrophohtc. In this state, it may precipitate to form a pritnaiy particle or deposit on an existing particle, micelle, or monomer drop. Estimates of the degree of polymerization necessary to cause precipitation have been given as 54 for vinyl acetate (Priest. 1952), 65 for methyl methacrylate (Fitch and Tsai, 1971), and 30 for styrene (Peppard, 1974). 

Keywords Colloidal dispersions Colloidal glasses Dynamics Grafted particles Hairy particles Micelles Nanoparticle-polymer hybrids Phase diagrams Polymers Rheology Soft colloids- Softness Stars... 

Recently, novel micellar systems based on block copolymers have been developed for drug solubilization and delivery (Houlton, 2003). One example of such a system is poly-ethylene glycol-poly-aspartic acid block copolymer, which spontaneously forms into colloidal particles (micelles) in aqueous solution. In this type of micelle, the drug molecule will experience an environment characterized by the physicochemical properties of the polymer (see Section 16.2.2.3). 

Radical propagation. The free radicals formed in the aqueous phase are hydrophilic and usually charged. Thus, they are very likely to react with monomer that is dissolved in the aqueous phase before entering particles, micelles, or droplets. 

In contrast, the free radicals should be produced in the aqueous phase in the case of partially soluble monomers. These free radicals, or oligoradicals, can diffuse into and out of the micelle or latex particles. Micelle-penetrating free radicals can either escape to the aqueous phase, react by propagation with... 

As a powerful methodology to assemble various components into soft supramolecular organizations, the LbL assembly method shows continuous progresses in the fields of drug delivery under the supramolecular concept (Fig. 2.2.5). The LbL method has excellent versatility for the assembly of various kinds of substances [13]. This method covers a wide range of available materials including proteins, nucleic acids, saccharides, virus particles micelles, vesicles, LB films, and other lipid membranes as well as conventional polyelectrolytes, conductive polymers, inorganic nanomaterials, nanocarbons, and dye... 

Solubilisates are colloidal solutions of a liquid in another liquid that is not miscible with it (see Sect. 18.3.3). The fat-soluble vitamins A, D and E are to be administered as solubilisates to patients with impaired fat absorption, such as patients with cystic fibrosis, to get the vitamins absorbed. Fat-soluble liquid active substances can be solubilised using surfactants, whereby colloidal particles, micelles, are formed. Relatively high concentrations of surfactants are necessary because they have to exceed the critical micelle concentration. Polysorbate 80 (see also Sect. 23.6.4) is... 

Periodic behavior is shown in Figure 11.3. Schork and Ray propose the following explanation. At 300 min, conversion increases rapidly because new polymer particles are formed and old ones grow. Additional surfactant adsorbs on the increased surface area of the particles. Micelles dissociate to contribute surfactant. 

This chapter is focused on spherical particles (micelles and vesicles) but should highlight that there has been increased recent interest in the preparation of cylindrical particles. This is due to recent realization of their advantages in comparison to spherical micellar morphologies with preferable properties being elicited in their application as templates for spherical micelles and nanowires as... 

In the case of liquid films that contain charged colloid particles (micelles), the oscillatory period. Ah, is considerably greater than the particle diameter [437,438], In this case, the theoretical prediction of Ah demands the use of density functional theory calculations and/or Monte Carlo simulations [456,512], However, the theory, simulations, and experiments showed that a simple inverse-cubic-root relation. Ah = exists between Ah and the bulk number concentration of micelles (particles), c , [437,438,498,512-514],... 

In the present study, electron spin resonance (ESR) spectra of a fatty-acid spin probe (16-doxylstearic acid, see Figure 19.1) incorporated into an oleic acid-oleate system were measured in order to get insight into the pH-dependent aggregation properties of sodium oleate and oleic acid. Furthermore, the dilution-induced transformation of submicrometer-sized particles (micelles and/or vesicles) into giant oleic acid-oleate vesicles was investigated by electrophoretic light scattering measurements. 

Emulsion polymerizations have also been performed in supercritical CO2. Here the monomer is CO2 insoluble (or only slightly soluble) but the initiator is CO2 soluble. Most of the monomer is dispersed as droplets in the CO2 that are stabilized by surfactant molecules adsorbed to the surface. Micelles are also present in emulsion polymerizations. The initiator is soluble in the CO2 phase but not in the monomer droplet, and thus the micelles act as the meeting place for the monomer and initiator. The systems contains three types of particles micelles where polymerization is not occurring, micelles where polymerization is occurring (called the polymer particle), and monomer droplets (Fig. 12). 

The introduction of a second colloidal component, whether it is a particle, micelle, or dissolved polymer, can induce depletion-induced attraction forces. - These forces can lead to the manipulation of the percolation network structure. The role of colloidal structures that can contribute to the final conducting percolation network has previously been modeled. - It was shown in these works that... 

The final system we consider in this tutorial is that of a spherical charged polyelectrolyte which serves as a model for a colloidal particle, micelle, or globular protein. The primary characteristic that differs between modeling a micelle and a protein at this level of representation is the much greater surface charge density associated with a micelle. A secondary, but still important, consideration, is the pK, values of the protein ionization sites, which might require use of boundary condition BC3 instead of BC2 as assumed below. °... 

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