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Hsu LY, Melo SG, Vazquez-Martel C, Spiegel CA, Ziebert F, Schwarz US, Blasco E. Alignment and actuation of liquid crystals via 3D confinement and two-photon laser printing. SCIENCE ADVANCES 2024; 10:eadq2597. [PMID: 39241061 PMCID: PMC11378907 DOI: 10.1126/sciadv.adq2597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2024] [Accepted: 08/01/2024] [Indexed: 09/08/2024]
Abstract
Liquid crystalline (LC) materials are especially suited for the preparation of active three-dimensional (3D) and 4D microstructures using two-photon laser printing. To achieve the desired actuation, the alignment of the LCs has to be controlled during the printing process. In most cases studied before, the alignment relied on surface modifications and complex alignment patterns and concomitant actuation were not possible. Here, we introduce a strategy for spatially aligning LC domains in three-dimensional space by using 3D-printed polydimethylsiloxane-based microscaffolds as confinement barriers, which induce the desired director field. The director field resulting from the boundary conditions is calculated with Landau de Gennes theory and validated by comparing experimentally measured and theoretically predicted birefringence patterns. We demonstrate our procedures for structures of varying complexity and then employed them to fabricate 4D microstructures that show the desired actuation. Overall, we obtain excellent agreement between theory and experiment. This opens the door for rational design of functional materials for 4D (micro)printing in the future.
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Affiliation(s)
- Li-Yun Hsu
- Institute for Molecular Systems Engineering and Advanced Materials (IMSEAM), Heidelberg University, Im Neuenheimer Feld 225, Heidelberg 69120, Germany
| | - Santiago Gomez Melo
- Institute for Theoretical Physics, Heidelberg University, Philosophenweg 19, Heidelberg 69120 Germany
- BioQuant, Heidelberg University, Im Neuenheimer Feld 267, Heidelberg 69120 Germany
| | - Clara Vazquez-Martel
- Institute for Molecular Systems Engineering and Advanced Materials (IMSEAM), Heidelberg University, Im Neuenheimer Feld 225, Heidelberg 69120, Germany
| | - Christoph A Spiegel
- Institute for Molecular Systems Engineering and Advanced Materials (IMSEAM), Heidelberg University, Im Neuenheimer Feld 225, Heidelberg 69120, Germany
| | - Falko Ziebert
- Institute for Theoretical Physics, Heidelberg University, Philosophenweg 19, Heidelberg 69120 Germany
- BioQuant, Heidelberg University, Im Neuenheimer Feld 267, Heidelberg 69120 Germany
| | - Ulrich S Schwarz
- Institute for Theoretical Physics, Heidelberg University, Philosophenweg 19, Heidelberg 69120 Germany
- BioQuant, Heidelberg University, Im Neuenheimer Feld 267, Heidelberg 69120 Germany
| | - Eva Blasco
- Institute for Molecular Systems Engineering and Advanced Materials (IMSEAM), Heidelberg University, Im Neuenheimer Feld 225, Heidelberg 69120, Germany
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Tasinkevych M, Park S, Mundoor H, Smalyukh II. Nanoparticle localization within chiral liquid crystal defect lines and nanoparticle interactions. Phys Rev E 2023; 107:034701. [PMID: 37073031 DOI: 10.1103/physreve.107.034701] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Accepted: 02/21/2023] [Indexed: 04/20/2023]
Abstract
Self-assembly of colloidal particles into predefined structures is a promising way to design inexpensive manmade materials with advanced macroscopic properties. Doping of nematic liquid crystals (LCs) with nanoparticles has a series of advantages in addressing these grand scientific and engineering challenges. It also provides a very rich soft matter platform for the discovery of unique condensed matter phases. The LC host naturally allows the realization of diverse anisotropic interparticle interactions, enriched by the spontaneous alignment of anisotropic particles due to the boundary conditions of the LC director. Here we demonstrate theoretically and experimentally that the ability of LC media to host topological defect lines can be used as a tool to probe the behavior of individual nanoparticles as well as effective interactions between them. LC defect lines irreversibly trap nanoparticles enabling controlled particle movement along the defect line with the use of a laser tweezer. Minimization of Landau-de Gennes free energy reveals a sensitivity of the ensuing effective nanoparticle interaction to the shape of the particle, surface anchoring strength, and temperature, which determine not only the strength of the interaction but also its repulsive or attractive character. Theoretical results are supported qualitatively by experimental observations. This work may pave the way toward designing controlled linear assemblies as well as one-dimensional crystals of nanoparticles such as gold nanorods or quantum dots with tunable interparticle spacing.
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Affiliation(s)
- Mykola Tasinkevych
- SOFT Group, School of Science and Technology, Nottingham Trent University, Clifton Lane, Nottingham NG11 8NS, United Kingdom
- Departamento de Física, and Centro de Física Teórica e Computacional, Faculdade de Ciências, Universidade de Lisboa, 1749-016 Lisboa, Portugal
- International Institute for Sustainability with Knotted Chiral Meta Matter, Hiroshima University, Higashihiroshima 739-8511, Japan
| | - Sungoh Park
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Haridas Mundoor
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Ivan I Smalyukh
- International Institute for Sustainability with Knotted Chiral Meta Matter, Hiroshima University, Higashihiroshima 739-8511, Japan
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
- Soft Materials Research Center; Department of Electrical, Computer, and Energy Engineering and Materials Science and Engineering Program; and Renewable and Sustainable Energy Institute, National Renewable Energy Laboratory, University of Colorado, Boulder, Colorado 80309, USA
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Senyuk B, Meng C, Smalyukh II. Design and Preparation of Nematic Colloidal Particles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2022; 38:9099-9118. [PMID: 35866261 DOI: 10.1021/acs.langmuir.2c00611] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Colloidal systems are abundant in technology, in biomedical settings, and in our daily life. The so-called "colloidal atoms" paradigm exploits interparticle interactions to self-assemble colloidal analogs of atomic and molecular crystals, liquid crystal glasses, and other types of condensed matter from nanometer- or micrometer-sized colloidal building blocks. Nematic colloids, which comprise colloidal particles dispersed within an anisotropic nematic fluid host medium, provide a particularly rich variety of physical behaviors at the mesoscale, not only matching but even exceeding the diversity of structural and phase behavior in conventional atomic and molecular systems. This feature article, using primarily examples of works from our own group, highlights recent developments in the design, fabrication, and self-assembly of nematic colloidal particles, including the capabilities of preprogramming their behavior by controlling the particle's surface boundary conditions for liquid crystal molecules at the colloidal surfaces as well as by defining the shape and topology of the colloidal particles. Recent progress in defining particle-induced defects, elastic multipoles, self-assembly, and dynamics is discussed along with open issues and challenges within this research field.
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Affiliation(s)
- Bohdan Senyuk
- Department of Physics, University of Colorado, Boulder, Colorado 80309, United States
| | - Cuiling Meng
- Department of Physics, University of Colorado, Boulder, Colorado 80309, United States
| | - Ivan I Smalyukh
- Department of Physics, University of Colorado, Boulder, Colorado 80309, United States
- Department of Electrical, Computer and Energy Engineering, University of Colorado, Boulder, Colorado 80309, United States
- Soft Materials Research Center and Materials Science and Engineering Program, University of Colorado, Boulder, Colorado 80309, United States
- Chemical Physics Program, Departments of Chemistry and Physics, University of Colorado, Boulder, Colorado 80309, United States
- Renewable and Sustainable Energy Institute, National Renewable Energy Laboratory and University of Colorado, Boulder, Colorado 80309, United States
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2D colloids in rotating electric fields: A laboratory of strong tunable three-body interactions. J Colloid Interface Sci 2021; 608:564-574. [PMID: 34626996 DOI: 10.1016/j.jcis.2021.09.116] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2021] [Revised: 09/05/2021] [Accepted: 09/20/2021] [Indexed: 11/20/2022]
Abstract
Many-body forces play a prominent role in structure and dynamics of matter, but their role is not well understood in many cases due to experimental challenges. Here, we demonstrate that a novel experimental system based on rotating electric fields can be utilised to deliver unprecedented degree of control over many-body interactions between colloidal silica particles in water. We further show that we can decompose interparticle interactions explicitly into the leading terms and study their specific effects on phase behaviour. We found that three-body interactions exert critical influence over the phase diagram domain boundaries, including liquid-gas binodal, critical and triple points. Phase transitions are shown to be reversible and fully controlled by the magnitude of external rotating electric field governing the tunable interactions. Our results demonstrate that colloidal systems in rotating electric fields are a unique laboratory to study the role of many-body interactions in physics of phase transitions and in applications, such as self-assembly, offering exciting opportunities for studying generic phenomena inherent to liquids and solids, from atomic to protein and colloidal systems.
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Senyuk B, Mozaffari A, Crust K, Zhang R, de Pablo JJ, Smalyukh II. Transformation between elastic dipoles, quadrupoles, octupoles, and hexadecapoles driven by surfactant self-assembly in nematic emulsion. SCIENCE ADVANCES 2021; 7:7/25/eabg0377. [PMID: 34144988 PMCID: PMC8213233 DOI: 10.1126/sciadv.abg0377] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2020] [Accepted: 05/05/2021] [Indexed: 06/12/2023]
Abstract
Emulsions comprising isotropic fluid drops within a nematic host are of interest for applications ranging from biodetection to smart windows, which rely on changes of molecular alignment structures around the drops in response to chemical, thermal, electric, and other stimuli. We show that absorption or desorption of trace amounts of common surfactants can drive continuous transformations of elastic multipoles induced by the droplets within the uniformly aligned nematic host. Out-of-equilibrium dynamics of director structures emerge from a controlled self-assembly or desorption of different surfactants at the drop-nematic interfaces, with ensuing forward and reverse transformations between elastic dipoles, quadrupoles, octupoles, and hexadecapoles. We characterize intertransformations of droplet-induced surface and bulk defects, probe elastic pair interactions, and discuss emergent prospects for fundamental science and applications of the reconfigurable nematic emulsions.
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Affiliation(s)
- Bohdan Senyuk
- Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, CO 80309, USA
| | - Ali Mozaffari
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, IL 60637, USA
| | - Kevin Crust
- Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, CO 80309, USA
| | - Rui Zhang
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, IL 60637, USA
- Department of Physics, The Hong Kong University of Science and Technology, Clear Water Bay, Kowloon, Hong Kong SAR
| | - Juan J de Pablo
- Pritzker School of Molecular Engineering, The University of Chicago, Chicago, IL 60637, USA.
- Center for Molecular Engineering, Argonne National Laboratory, Lemont, IL 60439, USA
| | - Ivan I Smalyukh
- Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, CO 80309, USA.
- Department of Electrical, Computer, and Energy Engineering and Materials Science and Engineering Program, University of Colorado, Boulder, CO 80309, USA
- Renewable and Sustainable Energy Institute, National Renewable Energy Laboratory and University of Colorado, Boulder, CO 80309, USA
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Everts JC, Senyuk B, Mundoor H, Ravnik M, Smalyukh II. Anisotropic electrostatic screening of charged colloids in nematic solvents. SCIENCE ADVANCES 2021; 7:7/5/eabd0662. [PMID: 33571118 PMCID: PMC7840135 DOI: 10.1126/sciadv.abd0662] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Accepted: 12/09/2020] [Indexed: 05/23/2023]
Abstract
The physical behavior of anisotropic charged colloids is determined by their material dielectric anisotropy, affecting colloidal self-assembly, biological function, and even out-of-equilibrium behavior. However, little is known about anisotropic electrostatic screening, which underlies all electrostatic effective interactions in such soft or biological materials. In this work, we demonstrate anisotropic electrostatic screening for charged colloidal particles in a nematic electrolyte. We show that material anisotropy behaves markedly different from particle anisotropy. The electrostatic potential and pair interactions decay with an anisotropic Debye screening length, contrasting the constant screening length for isotropic electrolytes. Charged dumpling-shaped near-spherical colloidal particles in a nematic medium are used as an experimental model system to explore the effects of anisotropic screening, demonstrating competing anisotropic elastic and electrostatic effective pair interactions for colloidal surface charges tunable from neutral to high, yielding particle-separated metastable states. Generally, our work contributes to the understanding of electrostatic screening in nematic anisotropic media.
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Affiliation(s)
- Jeffrey C Everts
- Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia
- Institute of Physical Chemistry, Polish Academy of Sciences, Kasprzaka 44/52, PL-01-224 Warsaw, Poland
| | - Bohdan Senyuk
- Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, CO 80309, USA
| | - Haridas Mundoor
- Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, CO 80309, USA
| | - Miha Ravnik
- Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana, Slovenia.
- Jozef Stefan Institute, Jamova 39, 1000 Ljubljana, Slovenia
| | - Ivan I Smalyukh
- Department of Physics and Soft Materials Research Center, University of Colorado, Boulder, CO 80309, USA.
- Department of Electrical, Computer and Energy Engineering and Materials Science and Engineering Program, University of Colorado, Boulder, CO 80309, USA
- Renewable and Sustainable Energy Institute, National Renewable Energy Laboratory, University of Colorado, Boulder, CO 80309, USA
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Garbovskiy Y, Emelyanenko AV, Glushchenko A. Inverse "guest-host" effect: ferroelectric nanoparticles mediated switching of nematic liquid crystals. NANOSCALE 2020; 12:16438-16442. [PMID: 32756694 DOI: 10.1039/d0nr05301e] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Liquid crystals are widely used as a host matrix to embed different materials: dyes, fullerenes, carbon nanotubes, various nanoparticles (metallic, semiconductor, ferromagnetic, ferroelectric). The usual approach is related to the so called "guest-host" effect: external electric (or magnetic) fields drive liquid crystals (host), and liquid crystals reorient embedded particles (guest). In this paper we report an experimental observation of the effect that is completely opposite to the classical "guest-host" phenomenon: ferroelectric nanoparticles being switched by an external field mediate the switching of liquid crystals. Our experiments show that ferroelectric nanoparticles reorient and hold liquid crystal molecules in a direction of the ferroelectric nanoparticles orientation even when an external electric field attempts to orient a liquid crystal in an orthogonal direction.
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Affiliation(s)
- Y Garbovskiy
- Department of Physics and Engineering Physics, Central Connecticut State University, New Britain, CT 06050, USA.
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