Szymański Jedrzej, Patkowski Adam, Wilk Agnieszka, Garstecki Piotr, Holyst Robert
Institute of Physical Chemistry PAS, Department III, Kasprzaka 44/52, 01-224 Warsaw, Poland.
J Phys Chem B. 2006 Dec 28;110(51):25593-7. doi: 10.1021/jp0666784.
Although water is the chief component of living cells, food, and personal care products, the supramolecular components make their viscosity larger than that of water by several orders of magnitude. Using fluorescence correlation spectroscopy (FCS), photon correlation spectroscopy (PCS), NMR, and rheology data, we show how the viscosity changes from the value for water at the molecular scale to the large macroviscosity. We determined the viscosity experienced by nanoprobes (of sizes from 0.28 to 190 nm) in aqueous micellar solution of hexaethylene-glycol-monododecyl-ether (in a range of concentration from 0.1% w/w to 35% w/w) and identified a clear crossover at the length scale of 17 +/- 2 nm (slightly larger than persistence length of micelles) at which viscosity acquires its macroscopic value. The sharp dependence of the viscosity coefficients on the size of the probe in the nanoregime has important consequences for diffusion-limited reactions in crowded environments (e.g., living cells).
尽管水是活细胞、食物和个人护理产品的主要成分，但超分子成分使其粘度比水大几个数量级。利用荧光相关光谱法（FCS）、光子相关光谱法（PCS）、核磁共振（NMR）和流变学数据，我们展示了粘度是如何从分子尺度上的水的粘度值变化到较大的宏观粘度的。我们测定了纳米探针（尺寸从0.28到190纳米）在六甘醇单十二烷基醚的胶束水溶液（浓度范围从0.1% w/w到35% w/w）中所经历的粘度，并确定在17±2纳米的长度尺度（略大于胶束的持久长度）处有一个明显的转变，在该长度尺度下粘度达到其宏观值。在纳米范围内粘度系数对探针尺寸的强烈依赖性对于拥挤环境（如活细胞）中的扩散受限反应具有重要影响。
