Self-assembly of magnetic nanoparticles in evaporating solution

Ji Yeon Ku, Deborah Michiko Aruguete, A. Paul Alivisatos, Phillip L. Geissler

Research output: Contribution to journalArticle

55 Citations (Scopus)

Abstract

When deposited from an evaporating solution onto a substrate, even nondescript nanoparticles can organize into intricate spatial patterns. Here we show that a simple but long-ranged anisotropy in nanoparticles' interactions can greatly enrich this scenario. In experiments with colloidal Co nanocrystals, which bear a substantial magnetic dipole, we observe assemblies quite distinct from those formed by nonmagnetic particles. Reflecting the strongly nonequilibrium nature of this process, nanocrystal aggregates also differ substantially from expected low-energy arrangements. Using coarse-grained computer simulations of dipolar nanoparticles, we have identified several dynamical mechanisms from which such unusual morphologies can arise. For particles with modest dipole moments, transient connections between growing domains frustrate phase separation into sparse and dense regions on the substrate. Characteristic length scales of the resulting cellular networks depend non-monotonically on the depth of quenches we use to mimic the effects of solvent evaporation. For particles with strong dipole moments, chain-like aggregates formed at early times serve as the agents of assembly at larger scales. Their effective interactions drive the formation of layered loop structures similar to those observed in experiments.

Original languageEnglish (US)
Pages (from-to)838-848
Number of pages11
JournalJournal of the American Chemical Society
Volume133
Issue number4
DOIs
StatePublished - Feb 2 2011

Fingerprint

Nanoparticles
Self assembly
Dipole moment
Nanocrystals
Substrates
Phase separation
Evaporation
Anisotropy
Experiments
Computer Simulation
Computer simulation

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

Cite this

Ku, Ji Yeon ; Aruguete, Deborah Michiko ; Alivisatos, A. Paul ; Geissler, Phillip L. / Self-assembly of magnetic nanoparticles in evaporating solution. In: Journal of the American Chemical Society. 2011 ; Vol. 133, No. 4. pp. 838-848.
@article{b8c6af2fb66d4695a6c91292a116072a,
title = "Self-assembly of magnetic nanoparticles in evaporating solution",
abstract = "When deposited from an evaporating solution onto a substrate, even nondescript nanoparticles can organize into intricate spatial patterns. Here we show that a simple but long-ranged anisotropy in nanoparticles' interactions can greatly enrich this scenario. In experiments with colloidal Co nanocrystals, which bear a substantial magnetic dipole, we observe assemblies quite distinct from those formed by nonmagnetic particles. Reflecting the strongly nonequilibrium nature of this process, nanocrystal aggregates also differ substantially from expected low-energy arrangements. Using coarse-grained computer simulations of dipolar nanoparticles, we have identified several dynamical mechanisms from which such unusual morphologies can arise. For particles with modest dipole moments, transient connections between growing domains frustrate phase separation into sparse and dense regions on the substrate. Characteristic length scales of the resulting cellular networks depend non-monotonically on the depth of quenches we use to mimic the effects of solvent evaporation. For particles with strong dipole moments, chain-like aggregates formed at early times serve as the agents of assembly at larger scales. Their effective interactions drive the formation of layered loop structures similar to those observed in experiments.",
author = "Ku, {Ji Yeon} and Aruguete, {Deborah Michiko} and Alivisatos, {A. Paul} and Geissler, {Phillip L.}",
year = "2011",
month = "2",
day = "2",
doi = "10.1021/ja107138x",
language = "English (US)",
volume = "133",
pages = "838--848",
journal = "Journal of the American Chemical Society",
issn = "0002-7863",
publisher = "American Chemical Society",
number = "4",

}

Self-assembly of magnetic nanoparticles in evaporating solution. / Ku, Ji Yeon; Aruguete, Deborah Michiko; Alivisatos, A. Paul; Geissler, Phillip L.

In: Journal of the American Chemical Society, Vol. 133, No. 4, 02.02.2011, p. 838-848.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Self-assembly of magnetic nanoparticles in evaporating solution

AU - Ku, Ji Yeon

AU - Aruguete, Deborah Michiko

AU - Alivisatos, A. Paul

AU - Geissler, Phillip L.

PY - 2011/2/2

Y1 - 2011/2/2

N2 - When deposited from an evaporating solution onto a substrate, even nondescript nanoparticles can organize into intricate spatial patterns. Here we show that a simple but long-ranged anisotropy in nanoparticles' interactions can greatly enrich this scenario. In experiments with colloidal Co nanocrystals, which bear a substantial magnetic dipole, we observe assemblies quite distinct from those formed by nonmagnetic particles. Reflecting the strongly nonequilibrium nature of this process, nanocrystal aggregates also differ substantially from expected low-energy arrangements. Using coarse-grained computer simulations of dipolar nanoparticles, we have identified several dynamical mechanisms from which such unusual morphologies can arise. For particles with modest dipole moments, transient connections between growing domains frustrate phase separation into sparse and dense regions on the substrate. Characteristic length scales of the resulting cellular networks depend non-monotonically on the depth of quenches we use to mimic the effects of solvent evaporation. For particles with strong dipole moments, chain-like aggregates formed at early times serve as the agents of assembly at larger scales. Their effective interactions drive the formation of layered loop structures similar to those observed in experiments.

AB - When deposited from an evaporating solution onto a substrate, even nondescript nanoparticles can organize into intricate spatial patterns. Here we show that a simple but long-ranged anisotropy in nanoparticles' interactions can greatly enrich this scenario. In experiments with colloidal Co nanocrystals, which bear a substantial magnetic dipole, we observe assemblies quite distinct from those formed by nonmagnetic particles. Reflecting the strongly nonequilibrium nature of this process, nanocrystal aggregates also differ substantially from expected low-energy arrangements. Using coarse-grained computer simulations of dipolar nanoparticles, we have identified several dynamical mechanisms from which such unusual morphologies can arise. For particles with modest dipole moments, transient connections between growing domains frustrate phase separation into sparse and dense regions on the substrate. Characteristic length scales of the resulting cellular networks depend non-monotonically on the depth of quenches we use to mimic the effects of solvent evaporation. For particles with strong dipole moments, chain-like aggregates formed at early times serve as the agents of assembly at larger scales. Their effective interactions drive the formation of layered loop structures similar to those observed in experiments.

UR - http://www.scopus.com/inward/record.url?scp=79851474012&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=79851474012&partnerID=8YFLogxK

U2 - 10.1021/ja107138x

DO - 10.1021/ja107138x

M3 - Article

VL - 133

SP - 838

EP - 848

JO - Journal of the American Chemical Society

JF - Journal of the American Chemical Society

SN - 0002-7863

IS - 4

ER -