Ultra-High Sensitivity Viscometer Based on a Torsion Pendulum
Xiao-Guang Ma1,5, Lan Chen1**, Hai-Yan Wang2, Jin-Xiu Zhang1,3, Xiao-Min Xiong1,3,4**
1School of Physics, Sun Yat-Sen University, Guangzhou 510275 2School of Information Technology, Guangdong Industry Polytechnic, Guangdong 510300 3State Key Laboratory of Optoelectronic Materials and Technologies, Guangzhou 510275 4Guangdong Provincial Key Laboratory of Photovoltaics Technologies, Guangzhou 510006 5Department of Physics, Hong Kong University of Science and Technology, Hong Kong
Abstract：Based on a conventional torsion pendulum, we develop a forced oscillation viscometer with ultra-high viscosity sensitivity of $2\times10^{-7}$ Pa$\cdot$s working at frequencies near the resonance. The viscosity is achieved by exploiting the phase lag for the angle displacement behind the torque, instead of the resonant curve, i.e., the variation of angle displacement amplitude versus frequency. The general formula for the measurement of the visco-elasticity of complex fluids is also presented. With such precision it is easy to measure tiny change in viscosity result from circumstantial influences. Deionized water and two kinds of NaCl aqueous solutions are chosen to demonstrate the performance of our home-made torsion pendulum-based viscometer.
2018, Vol. 35 
