Monodisperse polystyrene latex particles

The adsorption of fully and partially hydrolyzed (88%) polyvinyl alcohol (PVA) on 190-1lOOnm monodisperse polystyrene latex particles was investigated. The effect of molecular weight was investigated for 190 nm-size particles using the serum replacement adsorption and desorption methods. The adsorption density at the adsorption-isotherm plateau followed the relationships for the fully hydrolyzed... 

FIG. 1.8 Electron micrograph of cross-linked monodisperse polystyrene latex particles. The latex is a commercial product (d = 0.500 jun) sold as a calibration standard. (Photograph courtesy of R. S. Daniel and L. X. Oakford, California State Polytechnic University, Pomona, CA.)... 

DI water, monodispersed polystyrene latex particle and yeast suspension... 

Monodispersed polystyrene latex particles 1.049 pm in diameter (std dev = 0.0587 pm) were captured utilizing a radial flow parallel-plate mobility analyzer (Tardos et. al. 1984). The mobility of the particles was determined from measurements of the collection efficiency of the analyzer by sampling particle number density for the inlet and exit flows (Figure 3-10). The principle was fundamentally that of electrostatic precipitation. The particles were charged by a corona discharge. The particles capture efficiency in the mobility... 

TEM micrograph of monodisperse polystyrene latex particles produced by emulsion polymerisation... 

Polymers for Advanced Technologies 12, No.8, Aug. 2001, p.494-9 MONODISPERSED POLYSTYRENE LATEX PARTICLES FUNCTIONALIZED BY THE MACROMONOMER TECHNIQUE. II. APPLICATION IN IMMUNODIAGNOSIS Gibanel S Heroguez V Gnanou Y Aramendia E ... 

No. 7, 7th April 1998, p.2087-97 MONODISPERSE POLYSTYRENE LATEX PARTICLES FUNCTIONALISED BY THE MACROMONOMER TECHNIQUE... 

Fig. 1.16 Microscopic image of a mixture of monodisperse polystyrene latex particles 25 min (top) and 55 min (bottom) after adding 185 mg/L sodium polyacrylate polymers. Picture reprinted from A. Kose and S. Hachisu,...

Bucsi, A., Forcada, J., Gibanel, S., Heroguez, V., FontaniUe, M., and Gnanou, Y. 1998. Monodisperse polystyrene latex particles functionalized by the macromonomer technique. Macromolecules 31 2087-97. 

The range of applicability of the above theoretical approaches and numerical results can be estimated by comparing them with experimental results obtained, mostly, by direct optical microscope observation and for monodisperse polystyrene latex particles [8-10, 13, 14, 19, 21, 22, 34—36]. Several sets of experimental data have also been gathered using the AFM for latex [17, 20], colloid gold [62] or dendrimer suspensions [26]. One can also apply electron microscopy to determine particle... 

Ali, S. A. Sengupta, M. J., Preparation and characterization of monodisperse polystyrene latexes of varying particle sizes without the use of surfactants, Polym. Mater. Sci. Eng. 1991, 8, 243 250... 

A similar technique has been applied to the generation of monodisperse suspensions in water. This type of method was first used in medical field and then widely used to spray monodisperse solid particles such as polystyrene latex particles. Aerosols of solutes have also been produced by atomizing solutions of salt, sugar or methylene blue dye dissolved in water. In practical operations, a low concentration of solid particles in a solvent is recommended in order to avoid possible agglomeration of suspensions in the solvent. 

Calibration of these single-particle counters is usually carried out using monodisperse polystyrene latex or polyvinyl latex spheres, which are available in sizes from 0.1 to 3 /im and have a refractive index of 1.6 alternatively, aerosols with lower refractive indices may be generated from liquids such as dioctyl phthalate (m = 1.49). Whitby and Willeke (1979) discuss the... 

High molecular weight monodisperse polystyrene latexes have been prepared by this method [158]. A number of factors were found to influence the size and dispersity of the particles. The size decreased with increasing surfactant concentration and decreasing internal phase volume, and a more monodisperse latex... 

Earlier work (3) has shown that cleaned monodisperse polystyrene latexes stabilized with surface sulfate (and perhaps a few hydroxyl) groups an be used as model colloids. For example, the distribution of H ions in the electric double layer as determined by conductometric titration has been correlated with the particle diameter determined by ultracentrifugation (3). The conductometric titration gives two measures of the concentration of H+ ions the initial conductance of the latex and the amount of base required for neutralization. The number of H+ ions determined by conductance is always smaller than the number determined by titration. This difference is attributed to the distribution of the H+ ions in the electric double layer those closest to the particle surface contribute least to the overall conductance. This distribution is expressed as the apparent degree of dissociation a, which is defined as the ratio H+ ions... 

Narrow particle fractions approaching a monodisperse distribution are particularly easy to treat and characterize when the above equations are applied to experimental data. Figure 2 shows an example of the elution profile (fractogram) obtained by running a mixture of four samples of "monodisperse" polystyrene latex beads. It is clear from the figure that a rather precise value of retention volume Vr can be identified with each bead size. With Vr known, it is easy to obtain R and X from Equation 5 and thence particle diameter d from Equation 4. This operation, as noted, yields diameters accurate to approximately 1-3%. 

Particle sizes can be controlled precisely in some cases (albeit usually involving trial and error). For example, monodisperse polystyrene latexes suitable as calibration standards can be prepared conveniently by emulsion polymerization. 

Monodisper.se, spherical polystyrene latex particles in aqueous su.spension are available commercially in sizes ranging from 0.088 to about 2 m. Relative standard deviations in panicle size are usually less than 0% and sometimes less than 1%. The suspensions are manufactured industrially by emulsion polymerization. Monodisperse polyvinylioluene particles of somewhat larger diameter, up to 3.5 im. are also available. The properties of these systems are reviewed by Mercer (1973). 

Likewise, the polymer latex data of Figure 3.34 have a much higher slope (mass transfer coefficient) than would be expected from the latex particle dif-fusivity. Monodisperse polystyrene latexes have both suspension viscosities and... 

A double shielded Faraday cage was also used by Tardos et. al., (1984) for sampling the continuous flow of monodispersed aerosol of 1.049 pm polystyrene latex particles (std dev = 0.0587 pm). The total particles were captured on a filter over time t at currents of 10"13A. The double shielding was required for these small current. 

Figure 1.3 Electron micrographs of colloidal materials in which three, two, and one dimensions lie in the colloid range (bars indicate 1/am) (a) spherical particles of monodisperse polystyrene latex, (b) packed spherical particles of polystyrene latex, (c) fibres of chrysotile asbestos, (d) thin plates of kaolinite.

Comparison of theory with experiment. It will be shown in Section 13.3.2.1 that the flat plate potentials can be used to calculate the osmotic disjoining pressures in concentrated monodisperse sterically stabilized dispersions. Evans and Napper (1977) have compared the theoretical predictions using the above equations with those measured by Homola and Robertson (1976) for polystyrene latex particles stabilized by poly(oxyethylene) of molecular weight ca 2 000 in aqueous dispersion media. The elastic repulsion in the interpenetrational-plus-compressional domain was estimated from the following expression for the constant segment density model... 

Calibration curves are obtained by measuring the residence time of known-size standards (such as the monodisperse polystyrene latexes manufactured by Dow) at a given eluent ionic strength. Typically, 6-10 particle sizes in the submicron range are needed to produce an accurate curve. In addition, comparison of chromatogram peak areas for samples run through the column and bypass lines allow determination of the upper size limit for 100% recovery... 

The size distributions of colloidal suspensions of nanoparticles 74 nm to 14 nm in diameter are analyzed on-line. The sols are first diluted in water seeded with enough TFA to attain electrical conductivities in the range of 0.01 S/m. The solution is then finely dispersed into an atmosphere of CO2 via a Taylor cone-jet. The resisting electrospray of ultrafine droplets dries, transferring the solution particles virtually uncontaminated into the gas. There they are sized by means of a differential mobility analyzer and an inertial impactor of unusually high resolution. The technique is first tested successfully with previously calibrated monodisperse polystyrene latex (PSL) spheres 74 to 21 nm in diameter. It is then used to size a solution of colloidal silica with particle diameters nominally between 10 and 14 nm. 

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