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DC Field | Value | Language |
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dc.contributor.author | Misra, Chandeshwar | - |
dc.contributor.author | Gadige, Paramesh | - |
dc.contributor.author | Bandyopadhyay, Ranjini | - |
dc.date.accessioned | 2022-10-14T05:36:27Z | - |
dc.date.available | 2022-10-14T05:36:27Z | - |
dc.date.issued | 2023-01-15 | - |
dc.identifier.citation | Journal of Colloid and Interface Science - A, 2023, Vol. 630, p223 | en_US |
dc.identifier.issn | 0021-9797 | - |
dc.identifier.uri | http://hdl.handle.net/2289/8000 | - |
dc.description | Restricted Access. | en_US |
dc.description.abstract | Hypothesis: While the mechanical disruption of microscopic structures in complex fluids by large shear flows has been studied extensively, the effects of applied strains on the dielectric properties of macro- molecular aggregates have received far less attention. Simultaneous rheology and dielectric experiments can be employed to study the dynamics of sheared colloidal suspensions over spatiotemporal scales spanning several decades. Experiments: Using a precision impedance analyzer, we study the dielectric behavior of strongly sheared aqueous suspensions of thermoreversible hydrogel poly(N-isopropylacrylamide) (PNIPAM) particles at different temperatures. We also perform stress relaxation experiments to uncover the influence of large deformations on the bulk mechanical moduli of these suspensions. Findings: All the sheared PNIPAM suspensions exhibit distinct dielectric relaxation processes in the low and high frequency regimes. At a temperature below the lower consolute solution temperature (LCST), the complex permittivities of highly dense PNIPAM suspensions decrease with increase in applied oscilla- tory strain amplitudes. Simultaneously, we note a counter-intuitive slowdown of the dielectric relaxation dynamics. Contrary to our rheo-dielectric findings, our bulk rheology experiments, performed under iden- tical conditions, reveal shear-thinning dynamics with increasing strain amplitudes. We propose the shear- induced rupture of fragile clusters of swollen PNIPAM particles to explain our observations. Our work illus- trates that rheo-dielectric studies have enormous potential for providing deep insights into the length scale-dependent dynamical properties of complex systems such as dense suspensions and soft glasses. | en_US |
dc.language.iso | en | en_US |
dc.publisher | Elsevier | en_US |
dc.relation.uri | https://doi.org/10.1016/j.jcis.2022.10.002 | en_US |
dc.rights | 2022 Elsevier | en_US |
dc.subject | Rheo-dielectric | en_US |
dc.subject | Thermoresponsive hydrogels | en_US |
dc.subject | Segmental motion | en_US |
dc.subject | Counterion polarization | en_US |
dc.subject | Interfacial polarization | en_US |
dc.subject | Dense suspensions | en_US |
dc.subject | Rheology | en_US |
dc.subject | Shear-thinning | en_US |
dc.title | Dichotomous behaviors of stress and dielectric relaxations in dense suspensions of swollen thermoreversible hydrogel microparticles | en_US |
dc.type | Article | en_US |
Appears in Collections: | Research Papers (SCM) |
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File | Description | Size | Format | |
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2022_JCIS_Vol.630_p223.pdf Restricted Access | Restricted Access | 3.66 MB | Adobe PDF | View/Open Request a copy |
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