Institute for Systems Rheology, Guangzhou University, No. 230 West Outer Ring Road, Higher Education Mega-Center, Panyu District, Guangzhou 510006, China.
Neutron Science Platform, Songshan Lake Materials Laboratory, Dongguan 523808, China.
Int J Mol Sci. 2023 Feb 18;24(4):4107. doi: 10.3390/ijms24044107.
Concentration scaling on linear viscoelastic properties of cellular suspensions has been studied by rheometric characterisation of suspensions and human blood in a wide range of volume fraction under small amplitude oscillatory shear experiments. The rheometric characterisation results are analysed by the time-concentration superposition (TCS) principle and show a power law scaling of characteristic relaxation time, plateau modulus and the zero-shear viscosity over the concentration ranges studied. The results show that the concentration effect of suspensions on their elasticity is much stronger than that of human blood due to its strong cellular interactions and a high aspect ratio. For human blood, no obvious phase transition could be observed over the range of hematocrits studied here and with respect to a high-frequency dynamic regime, only one concentration scaling exponent could be identified. For suspensions with respect to a low-frequency dynamic regime, three concentration scaling exponents in the volume fraction Region I (0.36≤ϕ/ϕref≤0.46), Region II (0.59≤ϕ/ϕref≤2.89) and Region III (3.11≤ϕ/ϕref≤3.44) are identified. The image observation shows that the network formation of suspensions occurs as the volume fraction is increased from Region I to Region II; the sol-gel transition takes place from Region II to Region III. In combination with analysis of other nanoscale suspensions and liquid crystalline polymer solutions reported in the literature, it is revealed that such a power law concentration scaling exponent depends on colloidal or molecular interactions mediated with solvent and is sensitive to the equilibrium phase behaviour of complex fluids. The TCS principle is an unambiguous tool to give a quantitative estimation.
通过在小振幅振荡剪切实验中对悬浮液和人血在较宽体积分数范围内的流变特性进行研究，研究了线性粘弹性性质的浓度缩放。流变特性的结果通过时-浓度叠加（TCS）原理进行分析，结果表明，在所研究的浓度范围内，特征松弛时间、平台模量和零剪切粘度呈幂律缩放。结果表明，由于细胞间相互作用较强且高纵横比，悬浮液对其弹性的浓度效应比人血强得多。对于人血，在研究的血细胞比容范围内没有观察到明显的相转变，并且对于高频动态范围，只能识别一个浓度缩放指数。对于悬浮液，在低频动态范围内，在体积分数区域 I（0.36≤ϕ/ϕref≤0.46）、区域 II（0.59≤ϕ/ϕref≤2.89）和区域 III（3.11≤ϕ/ϕref≤3.44）中识别到三个浓度缩放指数。图像观察表明，随着体积分数从区域 I 增加到区域 II，悬浮液的网络形成；从区域 II 到区域 III 发生溶胶-凝胶转变。结合文献中报道的其他纳米悬浮液和液晶聚合物溶液的分析，表明这种幂律浓度缩放指数取决于溶剂介导的胶体或分子相互作用，并且对复杂流体的平衡相行为敏感。TCS 原理是定量估计的明确工具。
