title: Tracer microrheology study of a hydrophobically modified comblike associative polymer.
abstract: The viscoelastic properties of associative polymers are important not only for their use as rheology modifiers but also to understand their complex structure in aqueous media. In this study, the dynamics of comblike hydrophobically modified alkali swellable associative (HASE) polymers are probed using diffusing wave spectroscopy (DWS) based tracer microrheology. DWS-based tracer microrheology accurately probes the dynamics of HASE polymers, and the extracted microrheological moduli versus frequency profile obtained from this technique closely matches that obtained from rotational rheometry measurements. Quantitatively, however, the moduli extracted from DWS-based tracer microrheology measurements are slightly higher than those obtained using rotational rheometry. The creep compliance, elastic modulus, and relaxation time concentration scaling behavior exhibits a power-law dependence. The length scale associated with the elastic to glassy behavior change is obtained from the time-dependent diffusion coefficient. The Zimm-Rouse type scaling is recovered at high frequencies but shows a concentration effect switching from Zimm to more Rouse-like behavior at higher concentrations.
authors.affiliation: †Qatar Environmental and Energy Research Institute (QEERI), Qatar Foundation, Doha, Qatar.
authors.forename: Ahmed A
authors.initials: AA
authors.lastname: Abdala
authors.affiliation: ‡Malvern Instruments, Columbia, Maryland 21046, United States.
authors.forename: Samiul
authors.initials: S
authors.lastname: Amin
authors.affiliation: §Biomanufacturing Training and Education Center, North Carolina State University, Raleigh, North Carolina 27695-7928, United States.
authors.forename: John H
authors.initials: JH
authors.lastname: van Zanten
authors.affiliation: ∥Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, United States.
authors.forename: Saad A
authors.initials: SA
authors.lastname: Khan
mesh_terms: D057927:Hydrophobic and Hydrophilic Interactions; D011108:Polymers / Q000737:chemistry*; D012212:Rheology
chemical_list: D011108:Polymers