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Title: Fluctuation Effects on the Brush Structure of Mixed Brush Nanoparticles in Solution

Abstract

A potentially attractive way to control nanoparticle assembly is to graft one or more polymers on the nanoparticle, to control the nanoparticle–nanoparticle interactions. When two immiscible polymers are grafted on the nanoparticle, they can microphase separate to form domains at the nanoparticle surface. Here, we computationally investigate the phase behavior of such binary mixed brush nanoparticles in solution, across a large and experimentally relevant parameter space. Specifically, we calculate the mean-field phase diagram, assuming uniform grafting of the two polymers, as a function of the nanoparticle size relative to the length of the grafted chains, the grafting density, the enthalpic repulsion between the grafted chains, and the solvent quality. We find a variety of phases including a Janus phase and phases with varying numbers of striped domains. Using a nonuniform, random distribution of grafting sites on the nanoparticle instead of the uniform distribution leads to the development of defects in the mixed brush structures. Introducing fluctuations as well leads to increasingly defective structures for the striped phases. Furthermore, we find that the simple Janus phase is preserved in all calculations, even with the introduction of nonuniform grafting and fluctuations. We conclude that the formation of the Janus phase is moremore » realistic experimentally than is the formation of defect-free multivalent mixed brush nanoparticles.« less

Authors:
ORCiD logo [1]; ORCiD logo [1]
  1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Publication Date:
Research Org.:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1499037
Report Number(s):
SAND-2019-2234J
Journal ID: ISSN 1936-0851; 673000
Grant/Contract Number:  
AC04-94AL85000
Resource Type:
Accepted Manuscript
Journal Name:
ACS Nano
Additional Journal Information:
Journal Volume: 12; Journal Issue: 2; Journal ID: ISSN 1936-0851
Publisher:
American Chemical Society (ACS)
Country of Publication:
United States
Language:
English
Subject:
77 NANOSCIENCE AND NANOTECHNOLOGY; brush structure; field theory; mixed brush; nonuniform grafting; polymer nanocomposites; polymers; thermal fluctuations

Citation Formats

Koski, Jason P., and Frischknecht, Amalie L. Fluctuation Effects on the Brush Structure of Mixed Brush Nanoparticles in Solution. United States: N. p., 2018. Web. doi:10.1021/acsnano.7b08271.
Koski, Jason P., & Frischknecht, Amalie L. Fluctuation Effects on the Brush Structure of Mixed Brush Nanoparticles in Solution. United States. doi:10.1021/acsnano.7b08271.
Koski, Jason P., and Frischknecht, Amalie L. Thu . "Fluctuation Effects on the Brush Structure of Mixed Brush Nanoparticles in Solution". United States. doi:10.1021/acsnano.7b08271. https://www.osti.gov/servlets/purl/1499037.
@article{osti_1499037,
title = {Fluctuation Effects on the Brush Structure of Mixed Brush Nanoparticles in Solution},
author = {Koski, Jason P. and Frischknecht, Amalie L.},
abstractNote = {A potentially attractive way to control nanoparticle assembly is to graft one or more polymers on the nanoparticle, to control the nanoparticle–nanoparticle interactions. When two immiscible polymers are grafted on the nanoparticle, they can microphase separate to form domains at the nanoparticle surface. Here, we computationally investigate the phase behavior of such binary mixed brush nanoparticles in solution, across a large and experimentally relevant parameter space. Specifically, we calculate the mean-field phase diagram, assuming uniform grafting of the two polymers, as a function of the nanoparticle size relative to the length of the grafted chains, the grafting density, the enthalpic repulsion between the grafted chains, and the solvent quality. We find a variety of phases including a Janus phase and phases with varying numbers of striped domains. Using a nonuniform, random distribution of grafting sites on the nanoparticle instead of the uniform distribution leads to the development of defects in the mixed brush structures. Introducing fluctuations as well leads to increasingly defective structures for the striped phases. Furthermore, we find that the simple Janus phase is preserved in all calculations, even with the introduction of nonuniform grafting and fluctuations. We conclude that the formation of the Janus phase is more realistic experimentally than is the formation of defect-free multivalent mixed brush nanoparticles.},
doi = {10.1021/acsnano.7b08271},
journal = {ACS Nano},
number = 2,
volume = 12,
place = {United States},
year = {2018},
month = {1}
}

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