| 초록 |
Coffee ring structure, which is the final drying pattern of particulate suspension droplets, is the key factor to obtain the particulate film with uniform coated surface in various fields. Since Deegan et al. [abbreviated Nature, 389, 827-829, 1997] firstly reported, many studies have been conducted to address how to control drying to hinder coffee ring in evaporating suspension droplets. In this study, light scattering methods have been mainly adopted to quantitatively distinguish the temporal changes in drying dynamics of particulate suspensions with micron-sized silica and PS spheres. In particular, particle motions around edge and center regimes of suspension droplets were compared separately. From the characteristic mobility of particles in ergodic state based on diffusing wave spectroscopy (DWS), and the fast dynamics due to thermal fluctuations of particles in non-ergodic drying state based on multispeckle diffusing wave spectroscopy (MSDWS), real-time phenomena related to internal flow features could be experimentally clarified through the microrheological analysis. |
