Monodisperse polystyrene colloids

Goodwin and coworkers have made a rather extensive study of the experimental variables involved in the synthesis of emulsifier-free, monodisperse polystyrene colloids stabilized solely by end-groups derived from persulfate initiator [14]. They obtained particle sizes in the range of 100 to 1000 nm diameter by varying initiator... 

Chad E. Reese, Carol D. Guerrero, Jesse M. Weissman, Kangtaek Lee, and Sanford A. Asher Synthesis of highly charged, monodisperse polystyrene colloidal particles for the fabrication cf photonic crystals, J. Colloid Interface Sci., 232 (2000) 76-80... 

Goodwin, J. W. Ottewill, R. H. Pelton, R., Studies on the preparation and characterization of monodisperse polystyrene lattices V The preparation of cationic latices, Colloid Polymer Sci. 1979,257,61 69... 

Stratton,R. A. The dependence of non-newtonian viscosity on molecular weight for monodisperse polystyrene. J. Colloid Sci. 22,517-530 (1966). 

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... 

Thus the monodisperse polystyrene latex stabilized with strong-acid surface groups can be hydrolyzed to form a latex stabilized with the same number of nonionic hydroxyl groups, which in turn can be oxidized to form a latex stabilized with the same number of weak-acid carboxyl groups, thus offering model colloids with identical characteristics except for the type of chemically bound surface groups ---- strong-acid, weak-acid, non-... 

The foregoing methods developed for the preparation and characterization of monodisperse polystyrene latexes to be used as model colloids can also be applied to the characterization of industrial latexes. The recipes used for the preparation of these industrial latexes are complex, and most contain a small amount of a functional monomer, e.g., acrylic acid, 2-sulfoethyl methacrylate, or N-methylolacrylamide. These functional monomers are often predominantly water-soluble, so that their use may have several results (i) the monomer may polymerize in the aqueous phase to form a water-soluble polymer that remains in the serum ... 

Monodisperse spherical colloids and most of the applications derived from these materials are still in an early stage of technical development. Many issues still need to be addressed before these materials can reach their potential in industrial applications. For example, the diversity of materials must be greatly expanded to include every major class of functional materials. At the moment, only silica and a few organic polymers (e.g., polystyrene and polymethylmethacrylate) can be prepared as truly monodispersed spherical colloids. These materials, unfortunately, do not exhibit any particularly interesting optical, nonlinear optical or electro-optical functionality. In this regard, it is necessary to develop new methods to either dope currently existing spherical colloids with functional components or to directly deal with the synthesis of other functional materials. Second, formation of complex crystal structures other than closely packed lattices has been met with limited success. As a major limitation to the self-assembly procedures described in this chapter, all of them seem to lack the ability to form 3D lattices with arbitrary structures. Recent demonstrations based on optical trapping method may provide a potential solution to this problem, albeit this approach seems to be too slow to be useful in practice.181-184 Third, the density of defects in the crystalline lattices of spherical colloids must be well-characterized and kept below... 

Three-dimensionally ordered macroporous ceramic with high LR ion conductivity was prepared by colloidal crystal templating method using monodispersed polystyrene beads [12]. Monodispersed polystyrene beads with 3 pm diameter were dispersed in water and then filtrated by using a membrane filter under a small pressure difference. After this treatment, polystyrene beads were accumulated on the membrane filter with closed pack structure, as shown in Fig. 4.2. Then, the membrane consisting of accumulated polystyrene beads was removed from the membrane filter and put on a glass substrate. After drying at room temperature, the... 

After an aqueous dispersion of monodispersed spherical colloids was injected into the cell, a positive pressure was applied through the glass tube to force the solvent (water) to flow through the channels. The beads were accumulated at the bottom of the cell, and crystallized into a three-dimensional opaline lattice under continuous sonication. So far, we have successfully applied this approach to assemble monodispersed colloids (both polystyrene beads and silica spheres) into ccp lattices over areas of several square centimeters. This method is relatively fast opaline lattices of a few square centimeters in area could be routinely obtained within several days. This method is also remarkable for its flexibility it could be directly employed to crystallize spherical colloids of various materials with diameters between 200 nm and 10 pm into three-dimensional opaline lattices. In addition, this procedure could be easily modified to crystalhze spherical colloids with diameters as small as 50 nm. ... 

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.

M. Senna, J. Lee, Preparation of monodispersed polystyrene microspheies uniformly coated by magnetite via heterogeneous polymerization. Colloid Polym. Sci. 273, 76-82 (1995)... 

J. Lee, M. Senna, Preparation of monodispersed polystyrene microspheres uniformly coated by magnetite via heterogeneous polymerization. Colloid Polym. Sci. 1995,273, 76-82 (c) F. Camso, A.S. Susha, M. Giersig, H. Moh-wald. Magnetic core-shell particles preparation of magnetite multilayers on polymer latex microspheres, Adv. Mater. 1999, 11,950-953. 

A thermochromic hydrogel based on Bragg reflection has been reported (16). The described system consists of crystalline colloidal arrays of monodisperse polystyrene spheres embedded in a poly(iV-isopropyl acrylamide) (PNIPAM) hydrogel, which was prepared by first dispersing highly charged and monodisperse... 

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. 

Goodwin, J.W., Hearn, J., Ho, C.C., and Ottewill, R.H. (1974) Studies on preparation and characterization of monodisperse polystyrene lattices 3. Preparation without added surface-active agents. Colloid Polym. Sci., 252 (6), 464- 71. 

R.A. Stratton (/. Colloid Interface Sci. 22, 517 (1966)) provides r versus y data for five essentially monodisperse polystyrenes of different molecular weight. Do these data better fit the Carreau or modified Cross equations Stratton obtains rj values by extrapolating plots of rj versus t to t = 0. Do these equations give substantially different values Stratton s values at 183 °C are as follows ... 

In strongly interacting systems, such as suspensions of deionized charged colloids, mode coupling effects may well be important. Mode coupling plausibly leads one to expect long-time power-law decays of )- For monodisperse polystyrene spheres in water, this expectation has been verified(38). 

Goodwin JW, Hearn J, Ho CC, OttewUl RH (1974) Studies on the preparation tmd characterisation of monodisperse polystyrene laticee. Colloid Polym Sci 252(6) 464... 

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