Polystyrene nanoparticles Phase separation

Chromatographic approaches have been also used to separate nanoparticles from samples coupled to different detectors, such as ICP-MS, MS, DLS. The best known technique for size separation is size exclusion chromatography (SEC). A size exclusion column is packed with porous beads, as the stationary phase, which retain particles, depending on their size and shape. This method has been applied to the size characterization of quantum dots, single-walled carbon nanotubes, and polystyrene nanoparticles [168, 169]. Another approach is hydro-dynamic chromatography (HDC), which separates particles based on their hydro-dynamic radius. HDC has been connected to the most common UV-Vis detector for the size characterization of nanoparticles, colloidal suspensions, and biomolecules [170-172]. 

Addition of nanoparticles results in less coalescence of particles during the melt processing, causing improved compatibilization. For example, exfoliated clay compatibilization, snch as in a polycarbonate/polymethylmethacrylate (PC/ PMMA) system, polyphenylene oxide/polyamide (PPO/PA), polyamide/ethyl-ene propylene diene elastomer (PA/EPDM) rnbber, polystyrene/polymethyl-methacrylate (PS/PMMA), and polyvinyl fluoride/polyamide-6 (PVF/PA) blends, is affected by lowering the interfacial tension between the two phases that are phase separated. 

Yu et al. (2007) developed a phase separation technique to move the CdS nanoparticles reversibly in the perpendicular direction. The CdS nanoparticles were chemically bonded to polystyrene-b-(poly(methyl methacrylate)-co-poly(-methacrylic acid) (CdS)) (PS-b-(PMMA-co-PMAA(CdS))) brushes and could be vertically lowered into the brush by exposure to toluene, whereas they were lifted out of the brush by exposure to acetone (or ethanol). Hence, authors show the possible extension of movement by manipulating the thickness of two blocks of the polymer brushes. 

Figure 7.3 Transient morphologies of phase-separating polymer blends with and without nanoparticles, (a) Optical micrograph of a phase-separating deuterated polystyrene (dPS)/polybutadiene (PB) 70 30 critical mixture after coarsening for 1510 min at 25 °C [40] (b) snapshot of a Langevin dynamic simulation ofa critical (50 50) AB-mixture, with...

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