Shape Matters in Magnetic-Field-Assisted Assembly of Prolate Colloids
Pal, Antara LU ; De Filippo, Carlo Andrea ; Ito, Thiago LU ; Kamal, Md Arif ; Petukhov, Andrei V. ; De Michele, Cristiano and Schurtenberger, Peter LU
(2022)
In ACS Nano
16(2).
p.2558-2568
- Abstract
An anisotropic colloidal shape in combination with an externally tunable interaction potential results in a plethora of self-assembled structures with potential applications toward the fabrication of smart materials. Here we present our investigation on the influence of an external magnetic field on the self-assembly of hematite-silica core-shell prolate colloids for two aspect ratios ρ = 2.9 and 3.69. Our study shows a rather counterintuitive but interesting phenomenon, where prolate colloids self-assemble into oblate liquid crystalline (LC) phases. With increasing concentration, particles with smaller ρ reveal a sequence of LC phases involving para-nematic, nematic, smectic, and oriented glass phases. The occurrence of a smectic phase... (More)
An anisotropic colloidal shape in combination with an externally tunable interaction potential results in a plethora of self-assembled structures with potential applications toward the fabrication of smart materials. Here we present our investigation on the influence of an external magnetic field on the self-assembly of hematite-silica core-shell prolate colloids for two aspect ratios ρ = 2.9 and 3.69. Our study shows a rather counterintuitive but interesting phenomenon, where prolate colloids self-assemble into oblate liquid crystalline (LC) phases. With increasing concentration, particles with smaller ρ reveal a sequence of LC phases involving para-nematic, nematic, smectic, and oriented glass phases. The occurrence of a smectic phase for colloidal ellipsoids has been neither predicted nor reported before. Quantitative shape analysis of the particles together with extensive computer simulations indicate that in addition to ρ, a subtle deviation from the ideal ellipsoidal shape dictates the formation of this unusual sequence of field-induced structures. Particles with ρ = 2.9 exhibit a hybrid shape containing features from both spherocylinders and ellipsoids, which make their self-assembly behavior richer than that observed for either of the “pure” shapes. The shape of the particles with higher ρ matches closely with the ideal ellipsoids, as a result their phase behavior follows the one expected for a “pure” ellipsoidal shape. Using anisotropic building blocks and external fields, our study demonstrates the ramifications of the subtle changes in the particle shape on the field-directed self-assembled structures with externally tunable properties.
(Less)
- author
- Pal, Antara
LU
; De Filippo, Carlo Andrea
; Ito, Thiago
LU
; Kamal, Md Arif
; Petukhov, Andrei V.
; De Michele, Cristiano
and Schurtenberger, Peter
LU
- organization
- publishing date
- 2022-02-22
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- directed self-assembly, liquid crystals, magnetic anisotropic colloids, Monte Carlo (MC) simulation, particle shape-analysis, small-angle X-ray scattering (SAXS)
- in
- ACS Nano
- volume
- 16
- issue
- 2
- pages
- 11 pages
- publisher
- The American Chemical Society (ACS)
- external identifiers
-
- scopus:85125020361
- pmid:35138802
- ISSN
- 1936-0851
- DOI
- 10.1021/acsnano.1c09208
- language
- English
- LU publication?
- yes
- id
- cef8bc50-601a-4f30-bef3-a056e97824ea
- date added to LUP
- 2022-06-14 14:16:37
- date last changed
- 2024-06-27 07:50:07
@article{cef8bc50-601a-4f30-bef3-a056e97824ea,
abstract = {{<p>An anisotropic colloidal shape in combination with an externally tunable interaction potential results in a plethora of self-assembled structures with potential applications toward the fabrication of smart materials. Here we present our investigation on the influence of an external magnetic field on the self-assembly of hematite-silica core-shell prolate colloids for two aspect ratios ρ = 2.9 and 3.69. Our study shows a rather counterintuitive but interesting phenomenon, where prolate colloids self-assemble into oblate liquid crystalline (LC) phases. With increasing concentration, particles with smaller ρ reveal a sequence of LC phases involving para-nematic, nematic, smectic, and oriented glass phases. The occurrence of a smectic phase for colloidal ellipsoids has been neither predicted nor reported before. Quantitative shape analysis of the particles together with extensive computer simulations indicate that in addition to ρ, a subtle deviation from the ideal ellipsoidal shape dictates the formation of this unusual sequence of field-induced structures. Particles with ρ = 2.9 exhibit a hybrid shape containing features from both spherocylinders and ellipsoids, which make their self-assembly behavior richer than that observed for either of the “pure” shapes. The shape of the particles with higher ρ matches closely with the ideal ellipsoids, as a result their phase behavior follows the one expected for a “pure” ellipsoidal shape. Using anisotropic building blocks and external fields, our study demonstrates the ramifications of the subtle changes in the particle shape on the field-directed self-assembled structures with externally tunable properties.</p>}},
author = {{Pal, Antara and De Filippo, Carlo Andrea and Ito, Thiago and Kamal, Md Arif and Petukhov, Andrei V. and De Michele, Cristiano and Schurtenberger, Peter}},
issn = {{1936-0851}},
keywords = {{directed self-assembly; liquid crystals; magnetic anisotropic colloids; Monte Carlo (MC) simulation; particle shape-analysis; small-angle X-ray scattering (SAXS)}},
language = {{eng}},
month = {{02}},
number = {{2}},
pages = {{2558--2568}},
publisher = {{The American Chemical Society (ACS)}},
series = {{ACS Nano}},
title = {{Shape Matters in Magnetic-Field-Assisted Assembly of Prolate Colloids}},
url = {{http://dx.doi.org/10.1021/acsnano.1c09208}},
doi = {{10.1021/acsnano.1c09208}},
volume = {{16}},
year = {{2022}},
}