Sidebottom D L
Department of Physics, Creighton University, Omaha, Nebraska 68178, USA.
Phys Rev E Stat Nonlin Soft Matter Phys. 2007 Jul;76(1 Pt 1):011505. doi: 10.1103/PhysRevE.76.011505. Epub 2007 Jul 10.
We report static and dynamic light-scattering measurements of aqueous glucose solutions near their glass transition. Photon correlation spectroscopy reveals two relaxation processes present in the supercooled liquid: a nonexponential and nonhydrodynamic, alpha -relaxation occurring at short times and an exponential and hydrodynamic relaxation occurring at longer times. The slow relaxation is seen only in the polarized scattering geometry and is in many ways identical to the "ultraslow" mode recently observed by others in specially annealed molecular glass-forming liquids and attributed to the formation of long-range density correlations or "dynamic clusters." Static light scattering confirms the existence of excess scattering in our glucose solutions that is consistent with clusters in a size range between 30 and 60nm . The size of the clusters varies with the water content and the clustering appears to be associated with the percolation of a hydrogen-bonded glucose network.
我们报告了接近玻璃化转变温度的葡萄糖水溶液的静态和动态光散射测量结果。光子相关光谱揭示了过冷液体中存在的两个弛豫过程：短时间内发生的非指数且非流体动力学的α弛豫，以及长时间发生的指数且流体动力学弛豫。慢弛豫仅在偏振散射几何结构中可见，并且在许多方面与其他人最近在经过特殊退火的分子玻璃形成液体中观察到的“超慢”模式相同，该模式归因于长程密度相关性或“动态簇”的形成。静态光散射证实了我们的葡萄糖溶液中存在过量散射，这与尺寸范围在30至60纳米之间的簇一致。簇的大小随含水量而变化，并且聚类似乎与氢键连接的葡萄糖网络的渗滤有关。
