Optical Probe Diffusion in Polymer Solutions

摘要: The experimental literature on the motion of mesoscopic probe particles through polymer solutions is systematically reviewed. primary focus study diffusive small particles. Comparison made with measurements solution viscosities. A coherent description was obtained, namely that diffusion coefficient generally depends concentration as D_p = D_0 exp(-alpha c^nu). One finds alpha molecular weights ~ M^0.8, and \nu appears to have large-M small-M values a crossover linking them. does not simply track viscosity; instead, eta typically increases markedly increasing weight. In some systems, e.g., hydroxypropylcellulose:water, observed spectra are bi- or tri-modal. Extended analysis full phenomenology implies hydroxypropylcellulose characterized by single, concentration-independent, length scale approximately size coil. very few one sees re-entrant low-concentration-plateau behaviors uncertain interpretation; from their rarity, these reasonably interpreted corresponding specific chemical effects. True microrheological studies examining under influence known external force also examined. Viscosity true in many cases substantially smaller than viscosity measured macroscopic instrument.