1. Solid Rheology of Glassy Substances: Polymer and Colloidal Systems Gregory B. McKenna Texas Tech University Lubbock, TX USA
Dynamics of colloidal systems have often been compared to those of molecular glasses. Here we use thermosensitive PNIPAAM colloidal suspensions to examine the three signatures of aging in molecular glasses and how they pertain to the colloidal systems.
Using diffusing wave light scattering spectroscopy we can determine the dynamics of the PNIPAAM system upon ‘jumping’ through the glass concentration.
We find that the equivalents to the intrinsic isotherms, asymmetry of approach and memory effects are reproduced in the colloidal glass.
This is the first time that structural recovery in colloidal glasses has been directly probed and compared to the expectations for molecular glasses.
Figure 1. Effect of aging on dynamics of a PNIPAAM colloidal glass after jumps through glass concentration. a) effect of waiting time and b) effect of temperature.
Figure 2. a) asymmetry of approach and b) memory response of PNIPAAM colloidal glass upon jumps through the glass concentration.