Affiliations: Hal B. Wallis Research Facility, Eisenhower Medical Center, Rancho Mirage, California 92270, USA
Note: [*] Visiting Scientist, Honorary Member of The Institute of Physical and Chemical Research, Wako, Saitama, 351-01 Japan, and Advisor of the Institute for Super-Materials, ULVAC, Tsukuba, 300-26 Japan
Note: [**] Visiting Scientist
Note: [***] To whom reprint requests should be addressed at: Fachhochschule München, Lothstr. 34, D-8000 München 2, F.R. Germany
Abstract: The steady flow viscosity at shear rates 0 to 120 sec−1 and dynamic viscoelasticity at frequencies 0.02 to 0.8 Hz were determined for aqueous suspensions of uniform polystyrene microspheres of 1.0 μm diameter. Rheological properties of the microsphere suspensions were Newtonian for particle concentrations up to 32%. By introducing dextran and calcium chloride into the particle suspensions, non-Newtonian behavior was produced similar to that observed for human blood. The cooperative effects of dextran and calcium ions promoted aggregation of particles at a concentration as low as 12%. Thus, a suspension of uniform sized spherical polystyrene particles in aqueous solution of dextran may be made to mimic blood by controlling the surface charge on the polystyrene spheres using addition of calcium ions to the medium.
