Monodisperse particles preparation

Schmitt V, Leal-Calderon F, Bibette J (2003) Preparation of Monodisperse Particles and Emulsions by Controlled Shear. 227 195-215... 

Schluter AD (2005) A Covalent Chemistry Approach to Giant Macromolecules with Cylindrical Shape and an Engineerable Interior and Surface. 245 151-191 Schmitt V, Leal-Calderon F, Bibette J (2003) Preparation of Monodisperse Particles and Emulsions by Controlled Shear. 227 195-215... 

For the characterization of Langmuir films, Fulda and coworkers [75-77] used anionic and cationic core-shell particles prepared by emulsifier-free emulsion polymerization. These particles have several advantages over those used in early publications First, the particles do not contain any stabihzer or emulsifier, which is eventually desorbed upon spreading and disturbs the formation of a particle monolayer at the air-water interface. Second, the preparation is a one-step process leading directly to monodisperse particles 0.2-0.5 jim in diameter. Third, the nature of the shell can be easily varied by using different hydrophilic comonomers. In Table 1, the particles and their characteristic properties are hsted. Most of the studies were carried out using anionic particles with polystyrene as core material and polyacrylic acid in the shell. 

Interestingly, it was found that gold particles were not produced with monodisperse amorphous Si02 particles prepared by the method of Stober et al. [26]. Flence, silica... 

The preparation of ZnSe materials is an area of interest and study. The coordinating ability of the solvent used in the solvothermal synthesis of zinc selenide was demonstrated to play an important role in the nucleation and growth of nanocrystalline ZnSe.604 Thermolysis of bis [methyl( -hexyl)di-seleno]carbamato]zinc gave highly monodispersed particles characterized by electronic spectroscopy, photoluminescence, X-ray diffraction, and electron microscopy.605... 

Many synthetic methods for the preparation of nanodispersed material have been reported, several routes applying conventional colloidal chemistry, with others involving the kinetically controlled precipitation of nanocrystallites using organometallic compounds.3 6-343 Controlled precipitation reactions yield dilute suspensions of quasi-monodispersed particles. This synthetic method sometimes involves the use of seeds of very small particles for the subsequent growth of larger ones.359 360... 

Figure 3.6 Silica spheres with monodisperse particle size are expensive analytical gels of top performance. Silica spheres with determined particle size ranges are ideally suited for preparative chromatography. (Photo courtesy of SiliCycle.)...

Kreuter and Speiser [77] developed a dispersion polymerization producing adjuvant nanospheres of polymethylmethacrylate) (PMMA). The monomer is dissolved in phosphate buffered saline and initiated by gamma radiation in the presence and absence of influenza virions. These systems showed enhanced adjuvant effect over aluminum hydroxide and prolonged antibody response. PMMA particles could be distinguished by TEM studies and the particle size was reported elsewhere to be 130 nm by photon correlation spectroscopy [75], The particle size could be reduced, producing monodisperse particles by inclusion of protective colloids, such as proteins or casein [40], Poly(methylmethacrylate) nanoparticles are also prepared... 

Fig. 1.3.16 Monodisperse leaflet-like CuO particles prepared by phase transformation from 0.20 mol dm-3 CufOHfe precursor. (From Ref. 28.)...

Therefore, the most efficient preparation of monodispersed particles can be achieved by regulating the feed rate of reactants (= — dC/dt) as proportional to tm in the case of diffusion-controlled growth and to t1 in the case of reaction-controlled growth, as illustrated in Fig. 4.1.10. 

Essentially the same process can be used for the preparation of monodispersed particles of internally mixed composition. To do so, solutions containing two or more different metal salts are aged at elevated temperatures in the presence of urea. 

For each noble metal it appears that reaction parameters such as the nature of the precursor, temperature, and time have to be optimized. Recently a study of the electrochemical reduction of noble metals species in EG was undertaken by Bonnet et al. (28). Belter control of the experimental conditions leading to the preparation of monodisperse particles in the nanometer, submicrometer, and micrometer size range for various noble metals is expected from knowledge of the electrochemical fundamentals of the polyol process. 

Fig. 11.2.1 Two sieps to prepare monodisperse particles in dispersion polymerization (A) before and (B) after stable particles are made up.

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