Polymer interphase structure near nanoscale inclusions: Comparison between random walk theory and experiment

We propose a theory for the structure of the interphase in polymeric nanocomposites based on the freely-jointed chain near an impermeable spherical inclusion. The theory considers only the entropic exclusion between a polymer and the inclusion. The radius of gyration of the polymer chain and its dis...

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Bibliographic Details
Published inPolymer (Guilford) Vol. 51; no. 18; pp. 4259 - 4266
Main Authors Meth, Jeffrey S., Lustig, Steven Raymond
Format Journal Article
LanguageEnglish
Published Kidlington Elsevier Ltd 19.08.2010
Elsevier
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Summary:We propose a theory for the structure of the interphase in polymeric nanocomposites based on the freely-jointed chain near an impermeable spherical inclusion. The theory considers only the entropic exclusion between a polymer and the inclusion. The radius of gyration of the polymer chain and its distortion from spherical symmetry are perturbed strongly when the chain end is closer than 3Rg0 from the surface of the sphere, where Rg0 is the unperturbed radius of gyration. Also, the maximum expansion of the chain is bounded by (4/3)½, equal to a 15% increase. The shape of the polymer chain is elongated tangentially to the surface when the chain end originates in the interphase, but elongates radially due to entropic repulsion when the chain end is very close to the surface of the sphere. All the distortions of the polymer conformation from ideality, and hence the spatial extent of the interphase, occur within the depletion region associated with colloids. The model is used to explain recent experimental results showing that polymer chain dimensions increase in the presence of nanoparticles. The model quantitatively reproduces the observations at low filler loadings using no adjustable parameters, suggesting that entropic arguments can describe the majority of the effect there. [Display omitted]
Bibliography:ObjectType-Article-2
SourceType-Scholarly Journals-1
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content type line 23
ISSN:0032-3861
1873-2291
DOI:10.1016/j.polymer.2010.06.043