Polystyrene sphere

Experimental investigations of the model system of dye molecules adsorbed onto surfaces of polystyrene spheres have finuly established the sensitivity and surface specificity of the SHG method even for particles of micrometre size [117]. The surface sensitivity of die SHG process has been exploited for probing molecular transport across the bilayer in liposomes [118], for measurement of electrostatic potentials at the surface of small particles [119] and for imaging... 

Lest one be lulled into a false sense that, assuming that the JKR theory properly describes particle adhesion within its regime, DeMejo et al. [56] also reported that, for soda-lime glass particles with radii less than about 5 p.m, the contact radius varied, not as the predicted but, rather, as Similar results were reported for other systems including polystyrene spheres on polyurethane [58], as shown in Fig. 2, and for glass particles having radii between about 1 and 100 p,m on a highly compliant, plasticized polyurethane substrate [59] as illustrated in Fig. 3. 

An example of a Maugis-Pollock system is polystyrene particles having radii between about 1 and 6 p.m on a polished silicon substrate, as studied by Rimai et al. [64]. As shown in Fig. 4, the contact radius was found to vary as the square root of the particle radius. Similar results were reported for crosslinked polystyrene spheres on Si02/silicon substrates [65] and micrometer-size glass particles on silicon substrates [66]. 

Fig. 4. The contact radius as a function of the square root of the particle radius for polystyrene spheres on a silicon substrate (from ref. [64]).

Pol VG, Grisaru H, Gedanken A (2005) Coating noble metal nanocrystals (Ag, Au, Pd and Pt) on polystyrene spheres via ultrasound irradiation. Langmuir 21 3635-3640... 

Lanthanide-doped inverse photonic crystals have been reported.282 The lattices were prepared by infilling self-assembled polystyrene sphere templates with a mixture of zirconium alkoxide and europium at 450 °C, the polystyrene spheres were burnt out leaving hollow spheres of air, and the infilled material was converted to Zr02 Eu3+. The PL properties of the resulting photonic lattice were reported.282 The possibility of including phosphors into photonic lattices could lead to many... 

Figure 3. Various type of SERS active metallic nanostructures (a) metal-island films (b) metal-coated nanospheres (semi-nanoshells) (c) metal-coated random nanostructures and (d) polymer coatings embedded with metal nanoparticles. Inset An SEM image of silver-coated polystyrene spheres.

Zhang, R. Graf, K. Berger, R., Swelling of cross linked polystyrene spheres in toluene vapor, Appl. Phys. Lett. 2006, 89, 223114... 

Figure 10.4 (Plate 8) Polystyrene spheres prepared by emulsion polymerization methods. Because they may be packed together to form columns or beds, these spheres find applications in separations, ion exchange, and as supports for catalysts. (Photographs by John Olive)...

Fig. 10.15 The methods for capillary filling of nanotubes involves dispersal of the agent in a liquid capable of flowing into the nanotube followed by subsequent evaporation of the solvent to leave particles inside the tube. Nanotubes have been filled with polystyrene spheres and palladium nanocrystals using this method (Reprinted from Kim et al., 2005. With permission from American Chemical Society Reprinted from Tessonnier et al., 2005. With permission from Elsevier) (See Color Plates)...

Figure 8.1. Fluorescence spectra for three individual dye-impregnated polystyrene spheres in a hominally monodispersed hydrosol (from Ref. 1).

Under the conditions of Example 5-23 the rubber phase of the end product shows an interesting micro-morphology. It consists of particles of 1-3 microns diameter into which polystyrene spheres with much lower diameters are dispersed. These included polystyrene spheres act as hard fillers and raise the elastic modulus of polybutadiene. As a consequence, HIPS with this micro-morphology has a higher impact resistance without loosing too much in stiffness and hardness. This special morphology can be visualized with transmission electron microscopy. A relevant TEM-picture obtained from a thin cut after straining with osmium tetroxide is shown in Sect. 2.3.4.14. 

Measured extinction spectra for aqueous suspensions of polystyrene spheres—the light scatterer s old friend—are shown in Fig. 11.19. Water is transparent only between about 0.2 and 1.3 jam, which limits measurements to this interval. These curves were obtained with a Cary 14R spectrophotometer, a commonly available double-beam instrument which automatically adjusts for changing light intensity during a wavelength scan and plots a continuous, high-resolution curve of optical density. To reproduce the fine structure faithfully, the curves were traced exactly as they were plotted by the instru-... 

Kigure 11.19 Measured extinction by aqueous suspensions of polystyrene spheres with three different mean diameters. 

Figure 13.13 Measured matrix elements (left) for polystyrene spheres in water (mean radius 0.40 fim, wavelength 0.3250 fim). Measured matrix elements (right) for water droplets (mean radius 1.5 /xm, wavelength 0.6328 /xm). From Hunt and Huffman (1975).

Fig. 13.15. Polystyrene spheres, diameter 90 pm (a) AFM with ultrasonic excitation (b) corresponding UFM (c) AFM without ultrasonic excitation (d) corresponding UFM, with damaged area indicated by arrow 1 pm x 1 /on, except (d) 2 pm x 2 pm...

The viscosity of uniform, cross-linked polystyrene spheres of two different diameters was measured in benzyl alcohol at 30°C J... 

Figure 4.2—Stationary phases in ion chromatography. Schematic of a polystyrene sphere used as a cation exchanger. The polystyrene matrix is transformed into a resin that can exchange cations (e.g. DOWEX 4) or into an anion exchange resin (e.g. DOWEX - MSA-l, or Permutite" if R = CH,).

For HPLC, polystyrene spheres are available with pore sizes ranging from 5 nm up to hundreds of nanometers. Particles with a 5-p.m diameter yield up to 80 000 plates per meter of column length. Silica (Table 26-4) with controlled pore size provides 10 000-16 000 plates per meter. The silica is coated with a hydrophilic phase that minimizes solute adsorption. A hydroxylated polyether resin with a well-defined pore size can be used over the pH range 2-12, whereas silica phases generally cannot be used above pH 8. Particles with different pore sizes can be mixed to give a wider molecular size separation range. 

Diffraction-like effects in PGSE experiment, which had been discussed for diffusion in both impermeable and connected structure, were experimentally confined for a sample of water-saturated, loosely packed array of monodisperse polystyrene spheres. This success suggests... 

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