Nanoparticles micelles

The effect of increasing only the radius of curvature of the oil drop on the displacement of the contact fine while keeping the interfacial tension constant at 20 dyn/cm, is illustrated in Figs. 9 and 11. Figure 11 shows that for a radius of a curvature of 100 xm, there is virtually no movement of the contact fine from the base case due to the presence of nanoparticles/micelles even at volume fraction 0.25. However, when the radius of curvature is increased to 500 xm (recall Fig. 9), thereby decreasing the capillary pressure, the presence of nanoparticles at the same concentration moves the contact fine by 1 xm. 

We have considered the case of a fluid wedge that can deform under the action of the disjoining pressure. Our simulations show that the extent of deformation of the meniscus (or fluid interface) increases with increase in the volume fraction of nanoparticles/micelles, when a decrease in the diameter of micelles and with a decrease in the capillary pressure resisting the deformation is smaller. The resulting deformation of the meniscus causes the contact line to move so that it displaces the fluid that does not contain the micelles (oil) in favor of the fluid that contains it (aqueous surfactant solution). 

Polymeric poly(lactic acid), poly(glycolic acid), poly(alkylcyanoacrylate), poly(3-hydroxybutanoic acid), Poly(organophosphazene), poly(ethylene glycol), poly(caprolactone), poly(ethylene oxide), poly(amidoamine), poly(L-glutamic acid), polypropylene inline) Vesicles, nanospheres, nanoparticles, micelles, dendrimers... 

Most of the time, metal/dielectric nanocomposites are studied in the form of solutions or thin solid films on a substrate Colloids, doped and annealed glasses, sol-gels, surfactant-stabilized nanoparticles, micelles, two- or three-dimension self-assembled nanocomposites, self-organized mesoporous oxides filled with metals, electrochemically-loaded template membranes, metal-ion implanted crystals, nanocomposite films elaborated by laser ablation, cluster-beam deposition, radio-frequency sputtering, or nanolithography. 

One of the emerging strategies to overcome the drawbacks of dendrimers and dendritic nanomaterials is their hybridization with other types of nanoparticles, which is most commonly used in targeted cancer drug delivery. The tumor characteristic of enhanced permeability and retention (EPR) effect allows polymeric nanoparticles, micelles, and liposomes of relatively large size (typically 50-200 nm in diameter) to be selectively accumulated in tumor sites.[32] This size-based accumulation in tumor sites, called passive targeting, cannot be easily exploited by dendrimers due to their small size (<10 nm). In contrast, active... 

Lipshutz reported the first gold-catalyzed dehydrative cyclization of diols and triols in aqueous medium to the corresponding heterocycles 6 in good to excellent yield at room temperature. The reactions occur in nanoparticle micelles (TPGS-750-M) where the hydrophobic effect drives the dehydration reaction. The addition of salts was also shown to decrease reaction times (140L724). 

Works in which nanoparticles (micelles, liposomes, bubbles, nanocapsules), introduced into the bloodstream, are the means of delivering drugs to the tumor, and ultrasound is a factor stimulating drug release [1-3] and enhancing the therapeutic effect [4, 5], can be attributed to the field of ultrasonic nanomedicine. 

Keywords— Nanoparticles, micelles, drug delivery systems, multidrug resistance, doxorubicin. 

A large variety of drug delivery systems are described in the literature, such as liposomes (Torchilin, 2006), micro and nanoparticles (Kumar, 2000), polymeric micelles (Torchilin, 2006), nanocrystals (Muller et al., 2011), among others. Microparticles are usually classified as microcapsules or microspheres (Figure 8). Microspheres are matrix spherical microparticles where the drug may be located on the surface or dissolved into the matrix. Microcapsules are characterized as spherical particles more than Ipm containing a core substance (aqueous or lipid), normally lipid, and are used to deliver poor soluble molecules... 

In 2000, the first example of ELP diblock copolymers for reversible stimulus-responsive self-assembly of nanoparticles was reported and their potential use in controlled delivery and release was suggested [87]. Later, these type of diblock copolypeptides were also covalently crossUnked through disulfide bond formation after self-assembly into micellar nanoparticles. In addition, the encapsulation of l-anilinonaphthalene-8-sulfonic acid, a hydrophobic fluorescent dye that fluoresces in hydrophobic enviromnent, was used to investigate the capacity of the micelle for hydrophobic drugs [88]. Fujita et al. replaced the hydrophilic ELP block by a polyaspartic acid chain (D ). They created a set of block copolymers with varying... 

Generation of nanoparticles under Langmuir monolayers and within LB films arose from earlier efforts to form nanoparticles within reverse micelles, microemulsions, and vesicles [89]. Semiconductor nanoparticles formed in surfactant media have been explored as photocatalytic systems [90]. One motivation for placing nanoparticles within the organic matrix of a LB film is to construct a superlattice of nanoparticles such that the optical properties of the nanoparticles associated with quantum confinement are preserved. If mono-layers of capped nanoparticles are transferred, a nanoparticle superlattice can be con-... 

As a result of their size and of specific interactions, hydrophilic macromolecules or solid nanoparticles cause strong changes in micellar size and dynamics, and their structural and dynamic properties are strongly affected. In these cases, the distribution among reversed micelles can be only described by ad hoc models [13,123]. 

Moreover, stable liquid systems made up of nanoparticles coated with a surfactant monolayer and dispersed in an apolar medium could be employed to catalyze reactions involving both apolar substrates (solubilized in the bulk solvent) and polar and amphiphilic substrates (preferentially encapsulated within the reversed micelles or located at the surfactant palisade layer) or could be used as antiwear additives for lubricants. For example, monodisperse nickel boride catalysts were prepared in water/CTAB/hexanol microemulsions and used directly as the catalysts of styrene hydrogenation [215]. 

In addition, it is of interest to note that investigations of the microscopic processes leading to nucleation, growth, oriented growth by the surfactant monolayer, and growth inhibition of nanoparticles in reversed micelles and of confinement and adsorption effects on such phenomena represent an intriguing and quite unexplored research field [218]. 

Taking into account that the state of nanoparticles is thermodynamically unstable against an unlimited growth, the physicochemical processes allowing reversed micelles to lead to stable dispersions and to a size control of nanoparticles are ... 

It must be pointed out that formation and stabihzation of nanoparticles in reversed micelles are the result of a delicate equilibrium among many factors. In addition, lacking a general theory enabling the selection a priori of the optimal conditions for the synthesis of nanoparticles of a given material with the wanted properties, stable nanoparticles containing w/o microemulsions can be achieved only in some system-specific and experimentally selected conditions. 

Another method is based on the evaporation of a w/o microemulsion carrying a water-soluble solubilizate inside the micellar core [221,222], The contemporaneous evaporation of the volatile components (water and organic solvent) leads to an increase in the concentration of micelles and of the solubilizate in the micellar core. Above a threshold value of the solubilizate concentration, it starts to crystallize in confined space. Nanoparticle coalescence could be hindered by surfactant adsorption and nanoparticle dispersion within the surfactant matrix. 

Nanoparticles of Mn and Pr-doped ZnS and CdS-ZnS were synthesized by wrt chemical method and inverse micelle method. Physical and fluorescent properties wra cbaractmzed by X-ray diffraction (XRD) and photoluminescence (PL). ZnS nanopatlicles aniKaled optically in air shows higher PL intensity than in vacuum. PL intensity of Mn and Pr-doped ZnS nanoparticles was enhanced by the photo-oxidation and the diffusion of luminescent ion. The prepared CdS nanoparticles show cubic or hexagonal phase, depending on synthesis conditions. Core-shell nanoparticles rahanced PL intensity by passivation. The interfacial state between CdS core and shell material was unchan d by different surface treatment. 

CdS and CdS-ZnS core-shell nanoparticles were synthesized by inverse micelle method. Crystallinity of CdS nanoparticles was hexagonal structure under the same molar ratio of CM and S precursor. However it was changed easily to cubic structure under the condition of sonication or higher concentration of Cd than S precursor. The interfacial state betwran CdS core and shell material was unchanged by different surface treatment. 

The most intensive development of the nanoparticle area concerns the synthesis of metal particles for applications in physics or in micro/nano-electronics generally. Besides the use of physical techniques such as atom evaporation, synthetic techniques based on salt reduction or compound precipitation (oxides, sulfides, selenides, etc.) have been developed, and associated, in general, to a kinetic control of the reaction using high temperatures, slow addition of reactants, or use of micelles as nanoreactors [15-20]. Organometallic compounds have also previously been used as material precursors in high temperature decomposition processes, for example in chemical vapor deposition [21]. Metal carbonyls have been widely used as precursors of metals either in the gas phase (OMCVD for the deposition of films or nanoparticles) or in solution for the synthesis after thermal treatment [22], UV irradiation or sonolysis [23,24] of fine powders or metal nanoparticles. 

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