TY - JOUR
T1 - Temperature-Induced Aggregation in Portlandite Suspensions
AU - Bhagavathi Kandy, Sharu
AU - Mehdipour, Iman
AU - Neithalath, Narayanan
AU - Bauchy, Mathieu
AU - Garboczi, Edward
AU - Srivastava, Samanvaya
AU - Gaedt, Torben
AU - Sant, Gaurav
N1 - Funding Information:
The authors acknowledge the financial support for this research from the National Science Foundation (DMREF: 1922167), Department of Energy: Office of Fossil Energy via the National Energy Technology Laboratory (DE-FE0031718), and TRANSCEND: a joint UCLA-NIST Consortium that is funded by its industry and agency partners. This research was conducted in the Laboratory for the Chemistry of Construction Materials (LC) and the Electron Microscopy Core Facility at UCLA. As such, the authors gratefully acknowledge the support provided by these laboratories that has made operations possible. The contents of this paper reflect the views and opinions of the authors, who are responsible for the accuracy of the data sets presented herein, and do not reflect the views and/or policies of the funding agencies nor do the contents constitute a specification, standard, or regulation. 2 a
Publisher Copyright:
Copyright © 2020 American Chemical Society.
PY - 2020/9/15
Y1 - 2020/9/15
N2 - Temperature is well known to affect the aggregation behavior of colloidal suspensions. This paper elucidates the temperature dependence of the rheology of portlandite (calcium hydroxide: Ca(OH)2) suspensions that feature a high ionic strength and a pH close to the particle's isoelectric point. In contrast to the viscosity of the suspending medium (saturated solution of Ca(OH)2 in water), the viscosity of Ca(OH)2 suspensions is found to increase with elevating temperature. This behavior is shown to arise from the temperature-induced aggregation of polydisperse Ca(OH)2 particulates because of the diminution of electrostatic repulsive forces with increasing temperature. The temperature dependence of the suspension viscosity is further shown to diminish with increasing particle volume fraction as a result of volumetric crowding and the formation of denser fractal structures in the suspension. Significantly, the temperature-dependent rheological response of suspensions is shown to be strongly affected by the suspending medium's properties, including ionic strength and ion valence, which affect aggregation kinetics. These outcomes provide new insights into aggregation processes that affect the temperature-dependent rheology of portlandite-based and similar suspensions that feature strong charge screening behavior.
AB - Temperature is well known to affect the aggregation behavior of colloidal suspensions. This paper elucidates the temperature dependence of the rheology of portlandite (calcium hydroxide: Ca(OH)2) suspensions that feature a high ionic strength and a pH close to the particle's isoelectric point. In contrast to the viscosity of the suspending medium (saturated solution of Ca(OH)2 in water), the viscosity of Ca(OH)2 suspensions is found to increase with elevating temperature. This behavior is shown to arise from the temperature-induced aggregation of polydisperse Ca(OH)2 particulates because of the diminution of electrostatic repulsive forces with increasing temperature. The temperature dependence of the suspension viscosity is further shown to diminish with increasing particle volume fraction as a result of volumetric crowding and the formation of denser fractal structures in the suspension. Significantly, the temperature-dependent rheological response of suspensions is shown to be strongly affected by the suspending medium's properties, including ionic strength and ion valence, which affect aggregation kinetics. These outcomes provide new insights into aggregation processes that affect the temperature-dependent rheology of portlandite-based and similar suspensions that feature strong charge screening behavior.
UR - http://www.scopus.com/inward/record.url?scp=85091125556&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85091125556&partnerID=8YFLogxK
U2 - 10.1021/acs.langmuir.0c01798
DO - 10.1021/acs.langmuir.0c01798
M3 - Article
C2 - 32799535
AN - SCOPUS:85091125556
SN - 0743-7463
VL - 36
SP - 10811
EP - 10821
JO - Langmuir
JF - Langmuir
IS - 36
ER -