Polystyrene microspheres, monodispersed

Benner et al. suspended in water relatively monodisperse polystyrene microspheres, which contained a fluorescent dye, and they recorded fluorescence spectra. The spheres had a nominal diameter of 9.92 /im (with a 2% standard deviation). Figure 27 presents one of their experimental fluorescence spectra (b) together with elastic scattering spectra computed for a diameter of 9.92 /an (a) and for 9.99 fim (c). The structure of the fluorescence sp>ectrum is not in agreement with the Mie theory computation for a 9.92/xm diameter sphere, but it is quite consistent with the result predicted for a 9.99/xm diameter sphere. 

Polymer microspheres with monodispersed distribution in size are much perferable for phagocytosis assays, because the size dominantly governs phagocytosis of the microspheres by M< ). In addition, the microspheres should be prepared without any surfactants to exclude the influence of the soap molecules adsorbed onto the surface, on phagocytosis of the microspheres. We have synthesized monodispersed polystyrene microspheres by soap-free emulsion polymerization of styrene at 70 °C for 30 hr using potassium persulfate as a initiator [14]. The widely different diameters of the... 

CdS and CdS/polyacrylonitrile (PAN) nanocomposites were prepared by y-irradiation and emulsion polymerization by different groups (Qiao et al. 2000, Choi et al. 2003). In photoluminescence spectroscopy analysis, the maximum peak of CdS/PAN nanocomposites prepared by y-irradiation and emulsion polymerization was at about 485 nm, whereas the maximum peak of CdS nanocomposites was at about 460 nm. CdS-polystyrene nanocomposite microspheres were fabricated by gamma-ray irradiation (Wu et al. 2003). Dispersion polymerization induced by gamma-ray irradiation was exploited to prepare monodispersed polystyrene microspheres and CdS nanoparticles were generated on the polystyrene microsphere surface via subsequent precipitation reaction of Cd + with S released from the decomposition of Na2S203 upon gamma-ray irradiation (Equation 23.3). The TEM images demonstrated that well-dispersed CdS nanoparticles ( 23 nm) were attached to the surface of polystyrene microspheres of 380 nm. 

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. 

YD. Liu, B.J. Park, Y.H. Kim, H.J. Choi, Smart monodisperse polystyrene/ polyaniline core-shell structured hybrid microspheres fabricated by a controlled releasing technique and their electro-responsive characteristics, J. Mater. Chem., 2011, 21,17396. 

Figure 7 Experimental measurement and Lorenz-Mie theory predictions of the average absorption Cabs,i and scattering Csca,i cross-sections between 400 and 700 nm of monodisperse polystyrene latex microspheres with diameters d equal to (A and B) 2.02 pm and (C and D) 4.5 pm, respectively (Kandilian, 2014).

Table I. Diameters of the polystyrene microspheres and Smoluchowski rate constants for the monodisperse suspensions in 1 mol dm KCl...

In the male 200 g Sprague-Dawley rat, 20 ppm formaldehyde exposure for 4 h at rest delayed short-term clearance (0-50 h) of monodisperse polystyrene latex microspheres (about 1.7 un in diameter) labelled with Cr and inhaled for 20 min just prior to pollutant exposure. Exposure to 10 ppm formaldehyde did not produce significant effects however, this same concentration during treadmill exercise (8 m/min) caused a delay in short-term clearance (Phalen et al. 1994). 

Fig. 7 compares the experimentally measured (A and C) absorption Cahs,x and (B and D) scattering Csca,x cross-sections between 400 and 700 nm of monodisperse latex spheres 2.02 and 4.5 pm diameter with Lorenz—Mie theory predictions using the complex index of refraction of latex reported by Ma et al. (2003). Flere also, the good agreement between theoretical and experimental results successfully validated the experimental setup and the data analysis. Similar vaHdation has been performed with the same polydisperse polystyrene latex microspheres and randomly oriented and infinitely long glass fibers considered for validating the scattering phase function measurements, as illustrated in Fig. 6 (Berberoglu and Pilon, 2007).

Together with TEM, SEM investigations have been useful in the description of diblock copolymer polystyrene-/ -poly(acrylic acid) (PS-fc-PAA) particle formation (Figure 8.7), namely from vesicles and lamellae to unclosed and closed porous particles and on until final porous particles. Thus, Yu et al. have highlighted that these self-assembled microspheres have monodispersed nanopores that contribute to their high sorption capacity and sustained release behavior (Yu et al. 2014). 

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