Diffusion of Nanoparticles in Semidilute Polymer Solutions: Effect of Different Length Scales

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• 作者：Indermeet Kohli ; Ashis Mukhopadhyay
• 刊名：Macromolecules
• 出版年：2012
• 出版时间：August 14, 2012
• 年：2012
• 卷：45
• 期：15
• 页码：6143-6149
• 全文大小：332K
• 年卷期：v.45,no.15(August 14, 2012)
• ISSN：1520-5835

文摘

We used gold nanoparticles (NPs) to investigate the length-scale-dependent dynamics in semidilute poly(ethylene glycol) (PEG)鈥搘ater solutions. Fluctuation correlation spectroscopy was used to measure the diffusion coefficients (D) of the NPs as a function of their radius (R₀), PEG volume fraction (), and molecular weight (M_w). Our results indicate that the radius of gyration, R_g, of polymer chain is the crossover length scale for the NPs experiencing nanoviscosity or macroviscosity. The reduced diffusivity can be plotted on a single master curve as D₀/D = exp(伪(R₀/尉)^未) for R_g > R₀ and as D₀/D = exp(伪(R_g/尉)^未) for R_g 鈮?R₀, where D₀ is the diffusion coefficient in neat solvent, 尉 is the correlation length, 伪 = 1.63, and 未 = 0.89. In size regime, 尉 < R₀ < a(), where a() is the tube diameter for entangled polymer liquid, we found D ^鈥?.45 and independent of M_w. For R₀ > a(), D ^鈥? was obtained.