Saha Debasish, Joshi Yogesh M, Bandyopadhyay Ranjini
Soft Condensed Matter Group, Raman Research Institute, C. V. Raman Avenue, Sadashivanagar, Bangalore 560 080, India.
Soft Matter. 2014 May 14;10(18):3292-300. doi: 10.1039/c4sm00187g. Epub 2014 Mar 18.
The primary and secondary relaxation timescales of aging colloidal suspensions of Laponite are estimated from intensity autocorrelation functions obtained in dynamic light scattering (DLS) experiments. The dynamical slowing down of these relaxation processes are compared with observations in fragile supercooled liquids by establishing a one-to-one mapping between the waiting time since filtration of a Laponite suspension and the inverse of the temperature of a supercooled liquid that is rapidly quenched towards its glass transition temperature. New timescales associated with primary and secondary relaxation processes, such as the characteristic timescale associated with the slowdown of the secondary relaxation process and the glass transition time, are extracted to describe the phenomenon of dynamical arrest in Laponite suspensions. In results that are strongly reminiscent of those extracted from supercooled liquids approaching their glass transitions, it is demonstrated that a strong coupling exists between the primary and secondary relaxation processes of aging Laponite suspensions in the cage-forming regime. Furthermore, the experimental data presented here clearly demonstrate the self-similar nature of the aging dynamics of Laponite suspensions within a range of sample concentrations.
通过动态光散射（DLS）实验中获得的强度自相关函数，估算了锂皂石老化胶体悬浮液的初级和次级弛豫时间尺度。通过在锂皂石悬浮液过滤后的等待时间与朝着玻璃化转变温度快速淬火的过冷液体的温度倒数之间建立一一映射，将这些弛豫过程的动力学减慢与脆性过冷液体中的观测结果进行了比较。提取了与初级和次级弛豫过程相关的新时间尺度，例如与次级弛豫过程减慢相关的特征时间尺度和玻璃化转变时间，以描述锂皂石悬浮液中的动力学停滞现象。结果与从接近玻璃化转变的过冷液体中提取的结果非常相似，表明在笼形区域中，老化锂皂石悬浮液的初级和次级弛豫过程之间存在强耦合。此外，这里给出的实验数据清楚地证明了在一定样品浓度范围内锂皂石悬浮液老化动力学的自相似性质。
