Graduate School of Science and Technology, Niigata University, Niigata 950-2181, Japan.
Graduate School of Advanced Science and Technology, JAIST, Nomi 923-1292, Japan.
Biomolecules. 2020 Jan 17;10(1):155. doi: 10.3390/biom10010155.
The rheopectic behavior of sacran aqueous solutions, a natural giant molecular polysaccharide with a molecular weight of 1.6 × 10 g/mol, was investigated. When a low shear was applied to 1.0 wt.% sacran solution, the shear viscosity increased from 7.2 to 34 Pas. The increment in the viscosity was enhanced as the shear rate decreased. The shear viscosity was independent of the time at a shear rate of 0.8 s; simultaneously, thixotropic behavior was observed at shear rates higher than 1.0 s. A crossover was observed at 0.15 wt.% for the concentration dependence of both the viscosity increase and zeta potential, which was the vicinity of the helix transition concentration or gelation concentration. It was clear that the molecular mechanism for the rheopexy was different at lower and higher regions of the crossover concentration.
研究了相对分子质量为 1.6×10^6g/mol 的天然巨型分子多糖——壳聚糖水溶液的触变行为。当对 1.0wt%的壳聚糖溶液施加低剪切时，剪切黏度从 7.2Pa·s 增加到 34Pa·s。随着剪切速率的降低，黏度的增加得到增强。在剪切速率为 0.8s^-1 时，剪切黏度与时间无关；同时，在剪切速率高于 1.0s^-1 时观察到触变性。在浓度依赖性方面，黏度增加和 ζ 电势都存在一个交叉点，其位于螺旋转变浓度或凝胶浓度附近，约为 0.15wt%。很明显，在交叉浓度的较低和较高区域，触变的分子机制是不同的。
