Structure and rheology of nanoparticle–polymer suspensions

Handle URI:
http://hdl.handle.net/10754/599763
Title:
Structure and rheology of nanoparticle–polymer suspensions
Authors:
Srivastava, Samanvaya; Shin, Jung Hwan; Archer, Lynden A.
Abstract:
Structure and rheology of oligomer-tethered nanoparticles suspended in low molecular weight polymeric host are investigated at various particle sizes and loadings. Strong curvature effects introduced by the small size of the nanoparticle cores are found to be important for understanding both the phase stability and rheology of the materials. Small angle X-ray scattering (SAXS) and transmission electron microscopy measurements indicate that PEG-SiO 2/PEG suspensions are more stable against phase separation and aggregation than expected from theory for interacting brushes. SAXS and rheology measurements also reveal that at high particle loadings, the stabilizing oligomer brush is significantly compressed and produces jamming in the suspensions. The jamming transition is accompanied by what appears to be a unique evolution in the transient suspension rheology, along with large increments in the zero-shear, Newtonian viscosity. The linear and nonlinear flow responses of the jammed suspensions are discussed in the framework of the Soft Glassy Rheology (SGR) model, which is shown to predict many features that are consistent with experimental observations, including a two-step relaxation following flow cessation and a facile method for determining the shear-thinning coefficient from linear viscoelastic measurements. Finally, we show that the small sizes of the particles have a significant effect on inter-particle interactions and rheology, leading to stronger deviations from expectations based on planar brushes and hard-sphere suspension theories. In particular, we find that in the high volume fraction limit, tethered nanoparticles interact in their host polymer through short-range forces, which are more analogous to those between soft particles than between spherical polymer brushes. © 2012 The Royal Society of Chemistry.
Citation:
Srivastava S, Shin JH, Archer LA (2012) Structure and rheology of nanoparticle–polymer suspensions. Soft Matter 8: 4097. Available: http://dx.doi.org/10.1039/c2sm06889c.
Publisher:
Royal Society of Chemistry (RSC)
Journal:
Soft Matter
KAUST Grant Number:
KUS-C1-018-02
Issue Date:
2012
DOI:
10.1039/c2sm06889c
Type:
Article
ISSN:
1744-683X; 1744-6848
Sponsors:
This publication was based on work supported in part by Award No. KUS-C1-018-02, made by King Abdullah University of Science and Technology (KAUST) and by the National Science Foundation, Award No. DMR-1006323. Facilities available through the Cornell Center for Materials Research (CCMR) were used for this study.
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Publications Acknowledging KAUST Support

Full metadata record

DC FieldValue Language
dc.contributor.authorSrivastava, Samanvayaen
dc.contributor.authorShin, Jung Hwanen
dc.contributor.authorArcher, Lynden A.en
dc.date.accessioned2016-02-28T06:09:14Zen
dc.date.available2016-02-28T06:09:14Zen
dc.date.issued2012en
dc.identifier.citationSrivastava S, Shin JH, Archer LA (2012) Structure and rheology of nanoparticle–polymer suspensions. Soft Matter 8: 4097. Available: http://dx.doi.org/10.1039/c2sm06889c.en
dc.identifier.issn1744-683Xen
dc.identifier.issn1744-6848en
dc.identifier.doi10.1039/c2sm06889cen
dc.identifier.urihttp://hdl.handle.net/10754/599763en
dc.description.abstractStructure and rheology of oligomer-tethered nanoparticles suspended in low molecular weight polymeric host are investigated at various particle sizes and loadings. Strong curvature effects introduced by the small size of the nanoparticle cores are found to be important for understanding both the phase stability and rheology of the materials. Small angle X-ray scattering (SAXS) and transmission electron microscopy measurements indicate that PEG-SiO 2/PEG suspensions are more stable against phase separation and aggregation than expected from theory for interacting brushes. SAXS and rheology measurements also reveal that at high particle loadings, the stabilizing oligomer brush is significantly compressed and produces jamming in the suspensions. The jamming transition is accompanied by what appears to be a unique evolution in the transient suspension rheology, along with large increments in the zero-shear, Newtonian viscosity. The linear and nonlinear flow responses of the jammed suspensions are discussed in the framework of the Soft Glassy Rheology (SGR) model, which is shown to predict many features that are consistent with experimental observations, including a two-step relaxation following flow cessation and a facile method for determining the shear-thinning coefficient from linear viscoelastic measurements. Finally, we show that the small sizes of the particles have a significant effect on inter-particle interactions and rheology, leading to stronger deviations from expectations based on planar brushes and hard-sphere suspension theories. In particular, we find that in the high volume fraction limit, tethered nanoparticles interact in their host polymer through short-range forces, which are more analogous to those between soft particles than between spherical polymer brushes. © 2012 The Royal Society of Chemistry.en
dc.description.sponsorshipThis publication was based on work supported in part by Award No. KUS-C1-018-02, made by King Abdullah University of Science and Technology (KAUST) and by the National Science Foundation, Award No. DMR-1006323. Facilities available through the Cornell Center for Materials Research (CCMR) were used for this study.en
dc.publisherRoyal Society of Chemistry (RSC)en
dc.titleStructure and rheology of nanoparticle–polymer suspensionsen
dc.typeArticleen
dc.identifier.journalSoft Matteren
dc.contributor.institutionCornell University, Ithaca, United Statesen
kaust.grant.numberKUS-C1-018-02en
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