Polystyrene-based particles

This paper summarizes our recent studies related to production of nondegradable and biodegradable polymeric particles and their use in diverse biomedical applications. Nondegradable monosize polystyrene based particles were prepared in micron-size range by a phase inversion polymerization. Surfaces of these particles were then coated with styrene-acrylate copolymer layers in order to include different functional groups. These particles were radiolabelled with and succesfully used in... 

Affinity chromatography, polystyrene-based particles, 227 Albumin adsorption, nondegradable polystyrene-based particles, 227-229 Amperometric biosensors drawbacks, 110-111 reagendess enzyme electrode development, 111-112,113/ Amperometric enzyme electrodes for glucose determination, sandwich-type. See Sandwich-type amperometric enzyme electrodes for glucose determination... 

FA in ACN (B) nano-LC (Cl8 silica particle UV or MS with polystyrene-based monolith outlet frit),... 

Besides DNA adsorption driven by a positive potential (electrostatic adsorption) DNA was also wet-adsorbed at an open circuit on a home-made polystyrene-based carbon ink [110]. This ink was prepared by a 2 3 mixture of polystyrene and graphite particles in mesitylene, and then printed on a polyester film. DNA was wef-adsorbed over the ink at 37 °C overnight. The nature of the electrode surface (graphite particles embedded in a polystyrene... 

Cross-linked polystyrene porous particles (with 21 mol% DVB) have been prepared by the concentrated emulsion polymerization method, using either toluene or decane as the porogen and an aqueous solution of SDS as the continuous phase. Since toluene is a good solvent for polystyrene while decane is a nonsolvent , the morphologies obtained in the two cases were different. The particles based on toluene (with a volume fraction of dispersed phase of 78%) have very small pores which could not be detected in the SEM pictures. The pore size distribution, which has sizes between 20 and 50 A and was determined with an adsorption analyzer, almost coincides with that in a previous study [49] in which porous polystyrene beads have been prepared by suspension polymerization. In contrast, the porous particles based on decane have pore sizes as large as 0.1-0.3 pm, which could be detected in the SEM pictures [44a], and also larger surface areas (47 m2 g ) than those based on toluene (25 m2 g ). The main difference between the concentrated emulsion polymerization and the suspension polymerization consists of the much smaller volume fraction of continuous phase used in the former procedure. The gel-like emulsion that constitutes the precursor in the former case contains polyhedral cells separated by thin films of continuous phase. The polymerization of the cells does not... 

Later, Hosoya et al. 1931 prepared monodisperse polymer-based CSPs from chiral methacrylamides by co-polymerization onto the surface of polymeric particles. These are synthesized by a staged templated suspension polymerization using a two-step swelling method starting from polystyrene seed particles of 1 pm size used as shape templates, onto which methyl methacrylate and later the chiral methacrylamide is co-polymerized. 

Equipment and technique for HDC of silica sols are essentially the same as for SEC. The difference is that the packed bed of the separating column is composed of nonporous, rather than porous, particles. Typically, these particles are polystyrene-based beads, but glass or dense silica beads also are effective. Alternatively, a long, narrow capillary can be used as the separating medium [30]. 

Figure 46 (a) Micrograph of polystyrene-based magnetic monodisperse particles the particle diameter is 2.8 imi. (b) The particles are subjected to an external magnetic field. (From Ref. 86.)... 

The EOD coefficient ( drag) is defined as the ratio of the flux of water through the membrane to the flux of protons in the absence of a concentration gradient of water [224]. EOD increases with current density and often exceeds the ability of the membrane to redistribute water by back diffusion. A hydrodynamic model for electroosmosis has been developed [225] which treats ions as spherical particles moving in a continuous viscous medium. The model describes the variation of the EOD within polystyrene-based model membranes quite well. Several methods have been utilized to measure EOD coefficients including streaming potential measurements [226,227], the use of concentration cells [224,228], water flux measurements [191], DMFC experiments [229,230], and NMR spectroscopy [231]. Plots of n rag values for selected membranes are shown in Fig. 30. 

Figure 12.27. Comparison of (O) theoretically predicted diffusion curve based on Higuchi-Higuchi equation (12.40) with ( ) experimental results for oxygen permeation through poly(vinyl acetate) containing 0.28 volume fraction of polystyrene latex particles. (Peterson, 1968.)...

For the analysis of organic-soluble and water-soluble synthetic polymers, silica-based packing materials have not become as widely used as was originally envisioned (8). Major improvements in the properties of polymer-based supports have contributed to their increased use in GPC. Columns packed with polystyrene divinylbenzene particles are now as efficient as those filled with silica particles of the same size. Because polymer-based packings can be synthesized with very small (<60 A) and very large (>4000 A) pores, they provide better selectivity than silica columns for the separation of monomers, as well as for very high molecular weight (5-20 million dalton) polymers. 

Brijmohan, S. M. Shaw, M. T., Proton Exchange Membranes Based on Sulfo-nated Crosslinked Polystyrene Micro Particles Dispersed in Poly(dimethylsiloxane). Polymer 2006,47, 2856-2864. 

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