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Particle dynamics and relaxation in bimodal suspensions during drying using multispeckle diffusing wave spectroscopy
Author(s) -
Oh Gwi Jeong,
Hwang Ji Won,
Bong Ki Wan,
Jung Hyun Wook,
Lee Seong Jae
Publication year - 2017
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.15437
Subject(s) - suspension (topology) , relaxation (psychology) , brownian motion , drop (telecommunication) , particle (ecology) , diffusion , autocorrelation , chemical physics , dynamics (music) , particle size , materials science , chemistry , thermodynamics , physics , geology , mathematics , psychology , social psychology , telecommunications , oceanography , statistics , quantum mechanics , computer science , pure mathematics , acoustics , homotopy
The motion of polystyrene particles in a bimodal suspension drop during drying was characterized via multispeckle diffusing wave spectroscopy. The fast and slow dynamics of bimodal particles, which were expressed in terms of autocorrelation function data from two kinds of cameras, were well connected in short and long lag time regimes. Characteristic time of β‐relaxation, representing the rapid movement of bimodal particles, became lower in the short lag time region as the portion of small particles increased, reflecting their fast Brownian motion. The difference in the relaxation features between bimodal suspension with large and small particles and unimodal suspension with only large particles became more evident as the size ratio between particles was high. Drying temperature could encourage the particle movement at the early stages of drying, leading to lower relaxation time, and inversely retard the relaxation behavior when drying time further elapsed, due to the structural rearrangement of particles. © 2016 American Institute of Chemical Engineers AIChE J , 63: 1114–1121, 2017