AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands.
Phys Chem Chem Phys. 2020 Apr 29;22(16):8667-8671. doi: 10.1039/d0cp00215a.
We study the relation between the macroscopic viscoelastic properties of aqueous hyaluronan polymer solutions and the molecular-scale dynamics of water using rheology measurements, differential dynamic microscopy, and polarization-resolved infrared pump-probe spectroscopy. We observe that the addition of hyaluronan to water leads to a slowing down of the reorientation of a fraction of the water molecules. Near pH 2.4, the viscosity of the hyaluronan solution reaches a maximum, while the number of slowed down water molecules reaches a minimum. This implies that the water molecules become on average more mobile when the solution becomes more viscous. This observation indicates that the increase in viscosity involves the expulsion of hydration water from the surfaces of the hyaluronan polymers, and a bundling of the hyaluronan polymer chains.
我们使用流变学测量、差示动态显微镜和偏振分辨红外泵浦探测光谱研究了水合透明质酸聚合物溶液的宏观粘弹性性质与水分子的分子尺度动力学之间的关系。我们观察到，透明质酸的加入会导致一部分水分子的重取向速度减慢。在 pH 值为 2.4 附近，透明质酸溶液的黏度达到最大值，而被减缓的水分子数量达到最小值。这意味着当溶液变得更粘稠时，水分子的平均移动性增强。这一观察结果表明，黏度的增加涉及到从透明质酸聚合物表面驱逐水合水，以及透明质酸聚合物链的聚集。
