Polystyrene PS particles

Electrophoresis measurements provide a qualitative indication of the assembly of polymer multilayers on colloids [49,50], The -potential as a function of polyelectrolyte layer number for negatively charged polystyrene (PS) particles coated with poly(diallyldimethylam-monium chloride) (PDADMAC) and poly(styrenesulfonate) (PSS) are displayed in Figure... 

Dawkins and Taylor109 dispersed poly(methyl methacrylate) (PMMA) or polystyrene (PS) particles in n-alkanes stabilized by AB block copolymers of styrene and dimethyl-siloxane. In these cases, styrene blocks act as anchors and dimethylsiloxane blocks give a surface layer. The thickness 6 of the dimethylsiloxane layer was determined by viscosity measurements as a function of the molecular weight of dimethylsiloxane blocks. 

It was previously reported that the homopolymer surfactant PFOA successfully stabilized poly(methyl methacrylate) (PMMA) dispersion polymerizations (DeSimone et al., 1994 Hsiao et ah, 1995), but was not successful for styrene dispersion polymerizations (Canelas et al., 1996). In these styrene polymerizations, the C02 pressure used was 204 bar. However, later studies showed that both PFOA and poly(l,l-dihydroper-fluorooctyl methacrylate) (PFOMA) could stabilize polystyrene (PS) particles (Shiho and DeSimone, 1999) when a higher pressure was used. These polymerizations were conducted at 370 bar, 65 °C, and the particle size could be varied from 3 to 10 pm by varying the concentration of stabilizer. These homopolymer surfactants are less expensive and easier to synthesize than block copolymer surfactants and provide access to a large range of particle sizes. 

Figure 5. Volume fraction of polystyrene (PS) particles in zinc against the concentration of various surfactants at j = 0.5 kA til 2, 4 PS = 0.02 54 76 (a) Cetylpyrridinium chloride (A) Sodium dodecylsulphate (o) and Nonylphenol(etho ylate>28(pFopoxylate)i3 ( ) (b) ...

Same laser for Raman and one optical tweezers 647.1 nm Polystyrene (PS) particles 200 nm-10 pm PS Raman peak at 1,000 cm Sensitivity and spatial selectivity as a function of particle size were investigated... 

Figure 6.17 Schematic representation of a spherical polyelectrolyte brush in which linear chains of poly(acrylic acid) (PAA) are chemically grafted onto the surface of a colloidal polystyrene (PS) particle. L denotes thickness of the PAA brush. (After Guo and Ballauff, 2000.)...

Gan et al. compared the growth of poly(methyl methacrylate) (PMMA) and polystyrene (PS) particles in ternary cationic microemulsions [128]. Different growth patterns were observed, which was attributed to differences in the redistribution of the components during the reaction. The strong interactions between the polar MMA monomer and the... 

Several synthetic methods for preparing PEDOT nanoparticles have been reported including seed polymerization, emulsion polymerization and dispersion polymerization. There have been several reports related to PEDOT-coated particles and PEDOT hollow particles [43, 44], Dispersion polymerization has been applied for PEDOT-coated Polystyrene (PS) particle fabrication. lOOnm PS nanoparticles were used as the core material [44]. Poly aniline (PANi) nanofibers have been synthesized using interfacial polymerization without templates or functional dopants [45,46]. Scanning electron microscopy (SEM) images of PANi nanofibers are shown in Figure 14.3. 

Preparation of PS Particles. We produced monosize polystyrene (PS) particles by following a "phase inversion polymerization" technique which was described in detail elsewhere (23-27). In order to obtain PS particles with different size ranges, we studied a wide variety of solvent systems with different polarities (e.g., ethanol/waler, isopropanol/ water, and ethanol/2-methoxyethanol). We also changed concentrations of the stabilizer (i.e., polyacrylic acid, PAA), the initiator (i.e., 2,2 -azobisisobutyro-nitrile), and the monomer to control the size and die monodispersity of these particles. 

Kralj et al. (2006) studied the separation of polystyrene (PS) particles of diameters 2-6 pm in a dilute aqueous sucrose solution (having a density such that gravitational forces were zero since Pp = pf). At the low particle Reynolds numbers employed (<0.01), the drag force will be described by Stokes law. At steady state, the drag force will balance the dielectrophoretic force (equations (6.2.47)) ... 

Figure 9.2 Scanning electron micrographs (SEM) of various particles, (a) Polystyrene latex (( ) 50 OOOx magnification) and AgCI ((2) 15 OOOx magnification) particles are seen. Both size distribution and aggregation (maybe due to crosslinking) of polystyrene (PS) particles can be distinguished. Notice that the PS dispersion is monodisperse. Shaw (1992). Reproduced with permission from Elsevier, (b) Two different types of particles that represent extreme variations from spherical particles are seen (( ) shows tobacco virus particles and (2) shows clay particles). The clay (sodium kaolin-Ite) particles have a mean diameter of 0.2 pm. Hiementz and Rajagopalan (1997). Reproduced with permission from Taylor Francis...

We would like to stabilize polystyrene (PS) particles by using either the NPE15 surfactant or the classical SDS (sodium dodecyl sulfate) anionic surfactant. Which surfactant would you use and why (Use the HLB-CPP plot of Problem 7.6.)... 

Figure 5.19 Polystyrene (PS) particles of 0.64 im radius dried from aqueous suspension on a solid surface and imaged by scanning electron microscopy. Due to immersion forces the particles tend to aggregate ratherthan being isolated as in solution. Bare PS particles are...

Figure 6 shows polystyrene (PS) particles of an average diameter of 11.9 xm retained on a freshly excised piece of sheep trachea and on a surfactant film of dipalmitoylphosphatidylcholine (DPPC) in a modified Langmuir-Wilhelmy balance. The surface tension in both cases is approximately 30 mN/m, measured by a drop-spreading technique on the trachea and by a Wilhelmy plate in the surface balance. The aqueous substrate for the film in the balance was 0.9% NaCl with 55% sucrose. The density of the substrate was 1.26 g/mL, considerably higher than that of the particle (1.05 g/cm ). Most of the particles retained on the tracheal surface appear to be submerged in the substrate, and only a small segment of the spheres is exposed to air above the three-phase line. This is equivalent to the situation in the surface balance. 

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