Authors
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Cao, X.-Z. ; Merlitz, H. ; Wu, C.-X. ; Sommer, J.-U.
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Title
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Polymer-induced inverse-temperature crystallization of nanoparticles on a substrate
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Date
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09.12.2013
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Number
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39202
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Abstract
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Using molecular dynamics simulations, we study the properties of liquid state polymernanoparticle composites confined between two parallel substrates, with an attractive polymersubstrate interaction. Polymers are in the semidilute regime at concentrations far above the overlap point, and nanoparticles are in good solvent and without enthalpic attraction to the substrates. An increase of temperature then triggers the crystallization of nanoparticles on one of the two substrate surfacesa surprising phenomenon, which is explained in terms of scaling theory, such as through competing effects of adsorptionand correlation blobs. Moreover, we show that the first, closely packed layer of nanoparticles on the substrate increases the depletion attraction of additional nanoparticles from the bulk, thereby enhancing and stabilizing the formation of a crystalline phase on the substrate. Within the time frame accessible to our numerical simulations, the crystallization of nanoparticles was irreversible; that is, their crystalline phase, once created, remained undamaged after a decrease of the temperature. Our study leads to a class of thermoreactive nanomaterials, in which the transition between a homogeneous state with dissolved nanoparticles and a surface-crystallized state is triggered by a temperature jump.
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Publisher
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ACS Nano
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Wikidata
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Citation
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ACS Nano 7 (2013) 9920-9926
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DOI
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https://doi.org/10.1021/nn4037738
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Tags
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polymer nanoparticle crystallization depletion adsorption correlation
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