Dynamics of solvent-free grafted nanoparticles

Alexandros Chremos; Athanassios Z. Panagiotopoulos; Donald L. Koch

doi:10.1063/1.3679442

Dynamics of solvent-free grafted nanoparticles

Alexandros Chremos, Athanassios Z. Panagiotopoulos, Donald L. Koch

Research output: Contribution to journal › Article › peer-review

44 Scopus citations

Abstract

The diffusivity and structural relaxation characteristics of oligomer-grafted nanoparticles have been investigated with simulations of a previously proposed coarse-grained model at atmospheric pressure. Solvent-free, polymer-grafted nanoparticles as well as grafted nanoparticles in a melt were compared to a reference system of bare (ungrafted) particles in a melt. Whereas longer chains lead to a larger hydrodynamic radius and lower relative diffusivity for grafted particles in a melt, bulk solvent-free nanoparticles with longer chains have higher relative diffusivities than their short chain counterparts. Solvent-free nanoparticles with short chains undergo a glass transition as indicated by a vanishing diffusivity, diverging structural relaxation time and the formation of body-centered-cubic-like order. Nanoparticles with longer chains exhibit a more gradual increase in the structural relaxation time with decreasing temperature and concomitantly increasing particle volume fraction. The diffusivity of the long chain nanoparticles exhibits a minimum at an intermediate temperature and volume fraction where the polymer brushes of neighboring particles overlap, but must stretch to fill the interparticle space. © 2012 American Institute of Physics.

Original language	English (US)
Pages (from-to)	044902
Journal	The Journal of Chemical Physics
Volume	136
Issue number	4
DOIs	https://doi.org/10.1063/1.3679442
State	Published - Jan 26 2012
Externally published	Yes

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title = "Dynamics of solvent-free grafted nanoparticles",

abstract = "The diffusivity and structural relaxation characteristics of oligomer-grafted nanoparticles have been investigated with simulations of a previously proposed coarse-grained model at atmospheric pressure. Solvent-free, polymer-grafted nanoparticles as well as grafted nanoparticles in a melt were compared to a reference system of bare (ungrafted) particles in a melt. Whereas longer chains lead to a larger hydrodynamic radius and lower relative diffusivity for grafted particles in a melt, bulk solvent-free nanoparticles with longer chains have higher relative diffusivities than their short chain counterparts. Solvent-free nanoparticles with short chains undergo a glass transition as indicated by a vanishing diffusivity, diverging structural relaxation time and the formation of body-centered-cubic-like order. Nanoparticles with longer chains exhibit a more gradual increase in the structural relaxation time with decreasing temperature and concomitantly increasing particle volume fraction. The diffusivity of the long chain nanoparticles exhibits a minimum at an intermediate temperature and volume fraction where the polymer brushes of neighboring particles overlap, but must stretch to fill the interparticle space. {\textcopyright} 2012 American Institute of Physics.",

author = "Alexandros Chremos and Panagiotopoulos, {Athanassios Z.} and Koch, {Donald L.}",

note = "KAUST Repository Item: Exported on 2020-10-01 Acknowledged KAUST grant number(s): KUS-C1-018-02 Acknowledgements: The authors would like to thank Professor Fernando Escobedo and Hsiu-Yu Yu for helpful discussions and Professor Escobedo for suggesting the simulation model used in this work. This publication is based on work supported in part by Award No. KUS-C1-018-02, made by King Abdullah University of Science and Technology (KAUST). Additional support was provided by grant CBET-1033155 from the U.S. National Science Foundation (NSF). This publication acknowledges KAUST support, but has no KAUST affiliated authors.",

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AU - Panagiotopoulos, Athanassios Z.

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N1 - KAUST Repository Item: Exported on 2020-10-01 Acknowledged KAUST grant number(s): KUS-C1-018-02 Acknowledgements: The authors would like to thank Professor Fernando Escobedo and Hsiu-Yu Yu for helpful discussions and Professor Escobedo for suggesting the simulation model used in this work. This publication is based on work supported in part by Award No. KUS-C1-018-02, made by King Abdullah University of Science and Technology (KAUST). Additional support was provided by grant CBET-1033155 from the U.S. National Science Foundation (NSF). This publication acknowledges KAUST support, but has no KAUST affiliated authors.

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N2 - The diffusivity and structural relaxation characteristics of oligomer-grafted nanoparticles have been investigated with simulations of a previously proposed coarse-grained model at atmospheric pressure. Solvent-free, polymer-grafted nanoparticles as well as grafted nanoparticles in a melt were compared to a reference system of bare (ungrafted) particles in a melt. Whereas longer chains lead to a larger hydrodynamic radius and lower relative diffusivity for grafted particles in a melt, bulk solvent-free nanoparticles with longer chains have higher relative diffusivities than their short chain counterparts. Solvent-free nanoparticles with short chains undergo a glass transition as indicated by a vanishing diffusivity, diverging structural relaxation time and the formation of body-centered-cubic-like order. Nanoparticles with longer chains exhibit a more gradual increase in the structural relaxation time with decreasing temperature and concomitantly increasing particle volume fraction. The diffusivity of the long chain nanoparticles exhibits a minimum at an intermediate temperature and volume fraction where the polymer brushes of neighboring particles overlap, but must stretch to fill the interparticle space. © 2012 American Institute of Physics.

AB - The diffusivity and structural relaxation characteristics of oligomer-grafted nanoparticles have been investigated with simulations of a previously proposed coarse-grained model at atmospheric pressure. Solvent-free, polymer-grafted nanoparticles as well as grafted nanoparticles in a melt were compared to a reference system of bare (ungrafted) particles in a melt. Whereas longer chains lead to a larger hydrodynamic radius and lower relative diffusivity for grafted particles in a melt, bulk solvent-free nanoparticles with longer chains have higher relative diffusivities than their short chain counterparts. Solvent-free nanoparticles with short chains undergo a glass transition as indicated by a vanishing diffusivity, diverging structural relaxation time and the formation of body-centered-cubic-like order. Nanoparticles with longer chains exhibit a more gradual increase in the structural relaxation time with decreasing temperature and concomitantly increasing particle volume fraction. The diffusivity of the long chain nanoparticles exhibits a minimum at an intermediate temperature and volume fraction where the polymer brushes of neighboring particles overlap, but must stretch to fill the interparticle space. © 2012 American Institute of Physics.

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Dynamics of solvent-free grafted nanoparticles

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