Scaling Behavior of Dendritic Nanoparticle Mobility in Semidilute Polymer Solutions

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• 作者：Daan W. de Kort ; Wolf H. Rombouts ; Freek J. M. Hoeben ; Henk M. Janssen ; Henk Van As ; John P. M. van Duynhoven
• 刊名：Macromolecules
• 出版年：2015
• 出版时间：October 27, 2015
• 年：2015
• 卷：48
• 期：20
• 页码：7585-7591
• 全文大小：440K
• ISSN：1520-5835

文摘

In our studies on particle mobility in polymer solutions, we have investigated and determined self-diffusion coefficients of nanoparticles in semidilute solutions of poly(ethylene glycol) (PEG, M_w = 6, 20, 35, and 100 kDa). Specially designed PEGylated dendrimers with well-defined sizes (d_h = 3.4鈥?1.0 nm) and with internal ¹⁹F moieties allow for background-free ¹⁹F NMR diffusion measurements. This way, we were able to assess the self-diffusion coefficients as a function of particle diameter and length scales (correlation length, tube diameter, polymer radius of gyration) with high resolution. Scaling arguments allowed us to visualize a clear crossover between particles probing a lower apparent viscosity to near macroviscosity when the nanoparticle size is comparable to the PEG polymer coil size. The same arguments are shown to correctly predict particle diffusion coefficients as a function of polymer concentration when the particles are smaller than the polymer coils.