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Title: Interfacial Self-Assembly of Polyelectrolyte-Capped Gold Nanoparticles

Abstract

Here, we report on pH- and salt-responsive assembly of nanoparticles capped with polyelectrolytes at vapor–liquid interfaces. Two types of alkylthiol-terminated poly(acrylic acid) (PAAs, varying in length) are synthesized and used to functionalize gold nanoparticles (AuNPs) to mimic similar assembly effects of single-stranded DNA-capped AuNPs using synthetic polyelectrolytes. Using surface-sensitive X-ray scattering techniques, including grazing incidence small-angle X-ray scattering (GISAXS) and X-ray reflectivity (XRR), we demonstrate that PAA-AuNPs spontaneously migrate to the vapor–liquid interfaces and form Gibbs monolayers by decreasing the pH of the suspension. The Gibbs monoalyers show chainlike structures of monoparticle thickness. The pH-induced self-assembly is attributed to the protonation of carboxyl groups and to hydrogen bonding between the neighboring PAA-AuNPs. In addition, we show that adding MgCl 2 to PAA-AuNP suspensions also induces adsorption at the interface and that the high affinity between magnesium ions and carboxyl groups leads to two- and three-dimensional clusters that yield partial surface coverage and poorer ordering of NPs at the interface. We also examine the assembly of PAA-AuNPs in the presence of a positively charged Langmuir monolayer that promotes the attraction of the negatively charged capped NPs by electrostatic forces. Our results show that synthetic polyelectrolyte-functionalized nanoparticles exhibit interfacial self-assembly behavior similarmore » to that of DNA-functionalized nanoparticles, providing a pathway for nanoparticle assembly in general.« less

Authors:
 [1];  [1];  [2];  [1]; ORCiD logo [1]
  1. Ames Lab. and Iowa State Univ., Ames, IA (United States)
  2. Ames Lab., Ames, IA (United States)
Publication Date:
Research Org.:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22)
OSTI Identifier:
1409368
Report Number(s):
IS-J-9499
Journal ID: ISSN 0743-7463
Grant/Contract Number:
AC02-07CH11358
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Langmuir
Additional Journal Information:
Journal Volume: 33; Journal Issue: 43; Journal ID: ISSN 0743-7463
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY

Citation Formats

Zhang, Honghu, Nayak, Srikanth, Wang, Wenjie, Mallapragada, Surya, and Vaknin, David. Interfacial Self-Assembly of Polyelectrolyte-Capped Gold Nanoparticles. United States: N. p., 2017. Web. doi:10.1021/acs.langmuir.7b02359.
Zhang, Honghu, Nayak, Srikanth, Wang, Wenjie, Mallapragada, Surya, & Vaknin, David. Interfacial Self-Assembly of Polyelectrolyte-Capped Gold Nanoparticles. United States. doi:10.1021/acs.langmuir.7b02359.
Zhang, Honghu, Nayak, Srikanth, Wang, Wenjie, Mallapragada, Surya, and Vaknin, David. 2017. "Interfacial Self-Assembly of Polyelectrolyte-Capped Gold Nanoparticles". United States. doi:10.1021/acs.langmuir.7b02359.
@article{osti_1409368,
title = {Interfacial Self-Assembly of Polyelectrolyte-Capped Gold Nanoparticles},
author = {Zhang, Honghu and Nayak, Srikanth and Wang, Wenjie and Mallapragada, Surya and Vaknin, David},
abstractNote = {Here, we report on pH- and salt-responsive assembly of nanoparticles capped with polyelectrolytes at vapor–liquid interfaces. Two types of alkylthiol-terminated poly(acrylic acid) (PAAs, varying in length) are synthesized and used to functionalize gold nanoparticles (AuNPs) to mimic similar assembly effects of single-stranded DNA-capped AuNPs using synthetic polyelectrolytes. Using surface-sensitive X-ray scattering techniques, including grazing incidence small-angle X-ray scattering (GISAXS) and X-ray reflectivity (XRR), we demonstrate that PAA-AuNPs spontaneously migrate to the vapor–liquid interfaces and form Gibbs monolayers by decreasing the pH of the suspension. The Gibbs monoalyers show chainlike structures of monoparticle thickness. The pH-induced self-assembly is attributed to the protonation of carboxyl groups and to hydrogen bonding between the neighboring PAA-AuNPs. In addition, we show that adding MgCl2 to PAA-AuNP suspensions also induces adsorption at the interface and that the high affinity between magnesium ions and carboxyl groups leads to two- and three-dimensional clusters that yield partial surface coverage and poorer ordering of NPs at the interface. We also examine the assembly of PAA-AuNPs in the presence of a positively charged Langmuir monolayer that promotes the attraction of the negatively charged capped NPs by electrostatic forces. Our results show that synthetic polyelectrolyte-functionalized nanoparticles exhibit interfacial self-assembly behavior similar to that of DNA-functionalized nanoparticles, providing a pathway for nanoparticle assembly in general.},
doi = {10.1021/acs.langmuir.7b02359},
journal = {Langmuir},
number = 43,
volume = 33,
place = {United States},
year = 2017,
month =
}

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