Capillary Viscometer for Fully Automated Measurement of the Concentration and Shear Dependence of the Viscosity of Macromolecular Solutions

Abstract

The construction and operation of a novel viscometer/rheometer are described. The instrument is designed to measure the viscosity of a macromolecular solution while automatically varying both solute concentration and shear rate. Viscosity is calculated directly from Poiseuille's Law, given the measured difference in pressure between two ends of a capillary tube through which the solution is flowing at a known rate. The instrument requires as little as 0.75 ml of a solution to provide a full profile of viscosity as a function of concentration and shear rate, and can measure viscosities as high as 500 cP and as low as 1 cP, at shear rates between 10 and 2 × 103 s-1. The results of control experiments are presented to document the accuracy and precision of measurement at both low and high concentration of synthetic polymers and proteins.

Quantitative characterization of the concentration‐dependent interaction between molecules of Dextran 70 in aqueous solution: Measurement and analysis in the context of thermodynamic and compressible sphere models

“…The simplest interpretation of this observation is that the free energy of transfer of all three species is dominated by volume exclusion. The more extended or expanded a Dextran 70~75 000 23.5 6.5 [27] Ficoll 70~60 000~10~5 [21] BSA~65 000 3.6 3.5 [28][29][30] macromolecular species, the more volume it excludes to other macromolecules of the same species in solution, and the greater the repulsive free energy of interaction. [17] The interpretation of our results in the context of a compressible sphere model was motivated by the calculation of Chan and Dunston [19] indicating that within the semi-dilute range of concentrations, the gradual compression of individual polymer chains with increasing concentration is thermodynamically favored over the interpenetration of polymer chains.…”

The molecular basis of high viscosity of monoclonal antibodies (mAbs) at high concentration

“…An instrument that measures viscosity of protein solutions automatically by varying solute concentration and shear rate has been described (Grupi & Minton, 2012). By measuring the pressure difference between the two ends of the capillary filled with a protein solution flowing at a known rate, enables determination of the viscosity using the Hagen-Poiseuille equation.…”

Viscosity measurement based on the tapping-induced free vibration of sessile droplets using MEMS-based piezoresistive cantilevers

“…In these applications, a viscometer must be able to operate using a small sample volume because either only a limited volume of the target liquid is available or the target liquid is expensive. Viscosity can be calculated from the pressure drop and flow rate in a single fluid flow [19][20][21][22][23][24] or from the widths of co-flowing laminar streams 25,26 . Commercially available viscometers are based on various sensing principles, including the cone and plate, falling ball, rotating ball, vibrational and capillary sensing principles 16 .…”