Effective rheology mapping for characterizing polymer solutions utilizing ultrasonic spinning rheometry

Abstract

We propose a practical map representation termed rheology mapping for comprehensively evaluating the dependence of viscoelasticity on applied shear deformation and shear timescale represented by oscillation frequency, utilizing ultrasonic spinning rheometry (USR), which has excellent applicability to a wide variety of polymer solutions. The rheology mapping was applied to two typical kinds of polymer solutions. One is carboxymethyl cellulose (CMC) aqueous solution, a well-known viscous and shear thinning fluid. The other is polyacrylamide (PAM) aqueous solution generally considered as a viscoelastic fluid while its viscoelasticity is difficult to be evaluated by a standard torque-type rheometer. The rheology mapping for the solutions showed notable rheological properties. The viscoelasticity of both the CMC and PAM solutions vary widely from elastic to viscous, depending on the applied shear rate, strain, and oscillation frequency. The mapping also revealed the clear dependence of the viscosity of the solutions: the CMC solutions on the shear rate and the PAM solutions on the shear strain. These results provide quantitative support of findings in other reports associating these macroscopic properties with the microscopic dynamics of polymer coils.

A method for evaluating time‐resolved rheological functionalities of fluid foods

“…Validation of the present USR has been conducted in studies (Ohie et al, 2022; Yoshida, Tasaka, & Murai, 2019a) with a standard torque‐type rheometer (MCR 102, Anton Paar, Austria) with a plate–plate geometry. Using carboxymethyl cellulose aqueous solution, which is a representative shear‐thinning fluid (Benchabane & Bekkour, 2008), Yoshida, Tasaka, and Murai (2019a) compared flow curves evaluated by USR and the torque‐type rheometer.…”

“…In the theory of USR, the oscillatory flow generated by the cylindrical wall is measured by UVP, and the viscosity at each radial position is evaluated by analyzing the velocity information. The thickness of the fluid layer moving on the cylindrical wall is about δ v = ( ν /2π f o ) 1/2 , where ν is the kinematic viscosity (Ohie et al, 2022; Tasaka et al 2021). Spatial resolution of UVP in the direction of measurement line is 0.74 mm.…”

“…, where ν is the kinematic viscosity (Ohie et al, 2022;. Spatial resolution of UVP in the direction of measurement line is 0.74 mm.…”

“…Measurements of the fluid motion itself can be obtained and the rheological properties for each radial position locally in a vessel have been evaluated. The efficacy of USR has been verified by comparing with a standard torque‐type rheometer (Ohie, Yoshida, Tasaka, & Murai, 2022; Yoshida, Tasaka, & Murai, 2019a). USR has been used to investigate milli‐bubble/solid particle suspensions (Sakurai et al, 2013; Tasaka et al, 2015; Yoshida, Tasaka, & Murai, 2019b), an oil–water mixture (Ohie, Yoshida, Park, Tasaka, & Murai, 2020), porridge (Tasaka et al 2021), and gel–sol coexistent fluids (Yoshida, Tasaka, & Fischer, 2019; Yoshida, Tasaka, & Murai, 2017; Yoshida, Tasaka, Tanaka, Park, & Murai, 2018).…”

“…Measurements of the fluid motion itself can be obtained and the rheological properties for each radial position locally in a vessel have been evaluated. The efficacy of USR has been verified by comparing with a standard torque-type rheometer (Ohie, Yoshida, Tasaka, & Murai, 2022;Yoshida, Tasaka, & Murai, 2019a).…”