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Combining Microfluidics and Microrheology to Determine Rheological Properties of Soft Matter during Repeated Phase Transitions
Published on: April 19, 2018
Conformational and rheological properties of a quaternary ammonium salt of curdlan
Wu-Dan Cai1, Wen-Yi Qiu1, Zhi-Chao Ding1
1School of Food & Biological Engineering, Jiangsu University, Zhenjiang 212013, China.
Abstract:
This study investigated the chain conformation, microstructure, and rheological properties of a quaternary ammonium salt of curdlan (Qcurd) in aqueous medium. Results showed that Qcurd exhibited typical polyelectrolyte behavior in pure water, and the normal viscosity character was observed in 0.1 M NaCl aqueous solution. The weight-average molecular weight (Mw), z-average radius of gyration (Rg), hydrodynamic radius (Rh), conformational parameter (α), characteristic constant (a) and structure parameter (ρ) for Qcurd were determined as 8.08 × 104 g/mol, 26.7 nm, 15.0 nm, 0.54, 0.62, and 1.78, respectively, indicating that Qcurd existed as a flexible chain conformation in 0.1 M NaCl solution, verified by atomic force microscopy. Qcurd exhibited more pronounced shear-thinning behavior at higher concentrations. The flow behavior of Qcurd at different concentrations and temperature was well evaluated by power-law model and Arrhenius equation. Dynamic tests revealed that Qcurd showed oscillatory behaviors between a dilute solution and a weak elastic gel.
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