Title	Glassy dynamics in colloidal system
Authors	Ren, Simiao
Advisors	Lam, Chi Hang
Degree	Undergraduate
Issue Date	2018
Absctract	The Glassy Dynamic problem has long been an open question facing fierce debate in recent decades. Though many studies have been done and various models have been raised to understand the mystery of the dynamic arrest of glass problem, there is no consensus reached in the academia. With the help of optical microscopic imaging, long time video recording of polydispersive colloid system with different densities is performed. The video images of individual particle resolution provides us valuable data to analyze frame by frame the dynamic of colloidal glass and gain insights on the origin of the sudden drop of glass dynamical rates when approaching the critical packing density, analogous to the glass transition temperature Tg. The analysis is carried out mainly in the MATLAB programming language. The model chosen to cross-validate our results is the Distinguished Particle Lattice Model (DPLM) of glass. We observe predominantly ‘hopping’ motions in the dynamics. By analyzing the particle Mean Square Displacement (MSD) , we are able to show the dominance of the Hopping Events’ contribution in the MSD of the system, which controls the dynamical property of glass system. We also define the subsequent motion of the hopping particles to be returning and escaping. By analyzing long time after the particle hops, we show the dominance of the returning events over escaping event in high density cases. This implies that majority of the hopping event is followed by returning events which, we believe, is sufficient to cause the dynamic arrest.
Subjects	Glass -- Microstructure Colloids
Publisher	Hong Kong Polytechnic University
Rights	All rights reserved.