@article{tanner_amin_kloxin_zanten_2011, title={Microviscoelasticity of soft repulsive sphere dispersions: Tracer particle microrheology of triblock copolymer micellar liquids and soft crystals}, volume={134}, ISSN={["1089-7690"]}, DOI={10.1063/1.3578183}, abstractNote={Tracer particle microrheology using diffusing wave spectroscopy-based microrheology is demonstrated to be a useful method to study the dynamics of aqueous Pluronic™ F108 solutions, which are viewed as solutions of repulsive soft spheres. The measured zero-shear microviscosity of noncrystallizing micellar dispersions indicates micelle corona dehydration upon increasing temperature. Colloidal sphere thermal motion is shown to be exquisitely sensitive to the onset of crystallization in these micellar dispersions. High temperature dynamics are dominated by an apparent soft repulsive micelle–micelle interaction potential indicating the important role played by lubrication forces and ultimately micelle corona interpenetration and compression at sufficiently high concentrations. The measured microscopic viscoelastic storage and loss moduli are qualitatively similar to those experimentally observed in mechanical measurements on colloidal dispersions and crystals, and calculated from mode coupling theory of colloidal suspensions. The observation of subdiffusive colloidal sphere thermal motion at short time-scales is strong evidence that the observed microscopic viscoelastic properties reflect the dynamics of individual micelles rather than a dispersion of micellar crystallites.}, number={17}, journal={JOURNAL OF CHEMICAL PHYSICS}, author={Tanner, Shaun A. and Amin, Samiul and Kloxin, Christopher J. and Zanten, John H.}, year={2011}, month={May} }
 @article{zanten_amin_abdala_2004, title={Brownian motion of colloidal spheres in aqueous PEO solutions}, volume={37}, ISSN={["1520-5835"]}, DOI={10.1021/ma035250p}, abstractNote={The Brownian motion of colloidal spheres in aqueous poly(ethylene oxide) (PEO) solutions ranging in concentration from 0.2 to 15 wt % is measured with diffusing wave spectroscopy over more than 6 decades of time. The measured colloidal sphere mean-squared displacements are shown to satisfy the generalized Stokes−Einstein relation that relates the particle mean-squared displacement to the polymer solution shear modulus as the microrheological creep compliance calculated from the colloidal sphere Brownian motion was found to agree with that measured by mechanical rheometry. The microrheological zero shear viscosity concentration dependence for the entangled solution regime, η ∼ c4.7, is in agreement with that reported by others from mechanical rheometry measurements on polymer−good solvent solutions and is stronger than the tube model prediction, η ∼ c3.9. Essentially the entire deviation between the predicted and measured entangled solution regime zero shear viscosity concentration dependence is accounted ...}, number={10}, journal={MACROMOLECULES}, author={Zanten, JH and Amin, S and Abdala, AA}, year={2004}, month={May}, pages={3874–3880} }
 @article{amin_kermis_zanten_dees_zanten_2001, title={Concentration fluctuations in CTAB/NaSal solutions}, volume={17}, ISSN={["0743-7463"]}, DOI={10.1021/la010844b}, abstractNote={This report details a dynamic light scattering investigation of CTAB/NaSal solution concentration fluctuations over a wide range of CTAB concentration and NaSal:CTAB mole ratio. Two distinct relaxation times are observed for CTAB concentrations greater than or equal to 0.02 M. The hydrodynamic correlation length, ξH, associated with the fast relaxation mode is observed to depend on both the CTAB concentration and NaSal:CTAB mole ratio. In particular, the CTAB concentration scaling of ξH is shown to vary in a nonmonotonic manner with the NaSal:CTAB mole ratio. The scaling exponent is found to range from −0.25 to −0.67, where its minimum value is found for NaSal:CTAB mole ratios near 1.5−2.0. The amplitude of the slow relaxation mode is strongly correlated with the hydrodynamic correlation length for NaSal:CTAB mole ratios less than or equal to 2 thereby suggesting polymer/polyelectrolyte solution behavior at these conditions. The overall picture that emerges is that of a system where the competition among ...}, number={26}, journal={LANGMUIR}, author={Amin, S and Kermis, TW and Zanten, RM and Dees, SJ and Zanten, JH}, year={2001}, month={Dec}, pages={8055–8061} }