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Size dependence of microprobe dynamics during gelation of a discotic colloidal clay

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dc.contributor Massachusetts Institute of Technology. Department of Chemical Engineering
dc.contributor Massachusetts Institute of Technology. Department of Mechanical Engineering
dc.contributor Massachusetts Institute of Technology. Hatsopoulos Microfluids Laboratory
dc.contributor McKinley, Gareth H.
dc.contributor Doyle, Patrick S.
dc.contributor Rich, Jason P.
dc.creator Rich, Jason P.
dc.creator McKinley, Gareth H
dc.creator Doyle, Patrick S
dc.date 2013-08-02T17:39:00Z
dc.date 2013-08-02T17:39:00Z
dc.date 2011-03
dc.date 2010-12
dc.date.accessioned 2023-03-01T18:12:00Z
dc.date.available 2023-03-01T18:12:00Z
dc.identifier 01486055
dc.identifier 1520-8516
dc.identifier http://hdl.handle.net/1721.1/79768
dc.identifier Rich, Jason P., Gareth H. McKinley, and Patrick S. Doyle. Size Dependence of Microprobe Dynamics During Gelation of a Discotic Colloidal Clay. Journal of Rheology 55, no. 2 (2011): 273. © 2011 The Society of Rheology
dc.identifier https://orcid.org/0000-0001-8323-2779
dc.identifier.uri http://localhost:8080/xmlui/handle/CUHPOERS/279126
dc.description Soft materials, such as gels and colloidal glasses, often exhibit different rheological properties at bulk and microscopic scales as a result of their complex microstructure. This phenomenon has recently been demonstrated for a gel-forming aqueous dispersion of Laponite® clay [ Oppong et al. Phys. Rev. E 78, 021405 (2008) ]. For this material, microrheology reveals a significantly weaker gel and a longer gelation time than bulk measurements. By performing multiple particle tracking microrheology experiments with different probe sizes, we show that length-scale–dependent rheology is a general feature of Laponite® gels. Small changes in probe size are accompanied by order of magnitude differences in the observed rheological properties and gelation time. The probe dynamics also exhibit size-dependent spatial heterogeneities that help to elucidate a microstructural length scale in the system. Through analytical theory and Brownian dynamics simulations, we find that the correlations described by previous authors between successive displacements of individual probes are more directly a result of material elasticity than of microstructural confinement. The apparent gelation times of dispersions with different Laponite® concentrations exhibit a self-similar dependence on probe size, suggesting a superposition of Laponite® concentration and probe size. From these observations, we propose an accordant description of the microstructural evolution of the gel.
dc.description American Chemical Society (Petroleum Research Fund (ACS-PRF Grant No. 49956-ND9))
dc.description United States. Dept. of Defense (National Defense Science and Engineering Graduate Fellowship)
dc.format application/pdf
dc.language en_US
dc.publisher Society of Rheology
dc.relation http://dx.doi.org/10.1122/1.3532979
dc.relation Journal of Rheology
dc.rights Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use.
dc.source MIT Web Domain
dc.title Size dependence of microprobe dynamics during gelation of a discotic colloidal clay
dc.type Article
dc.type http://purl.org/eprint/type/JournalArticle


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