1
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Skačej G, Querciagrossa L, Zannoni C. On the Effects of Different trans and cis Populations in Azobenzene Liquid Crystal Elastomers: A Monte Carlo Investigation. ACS Appl Polym Mater 2023; 5:5805-5815. [PMID: 37588085 PMCID: PMC10426334 DOI: 10.1021/acsapm.3c00361] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Accepted: 07/13/2023] [Indexed: 08/18/2023]
Abstract
We investigate main-chain liquid crystal elastomers (LCEs) formed by photoresponsive azobenzene units with different populations of trans and cis conformers (from fully trans to fully cis). We study their macroscopic properties as well as their molecular organization using extensive Monte Carlo simulations of a simple coarse-grained model where the trans and cis conformers are represented by soft-core biaxial Gay-Berne particles with size and interaction energy parameters obtained by fitting a bare bone azobenzene moiety represented at atomistic level. We find that increasing the fraction of cis conformers, as could be obtained by near-UV irradiation, shifts the nematic-isotropic transition to a lower temperature, consistently with experiment, while generating internal stress in a clamped sample. An analysis of pair distributions shows that the immediate surroundings of a bent cis molecule are slightly less dense and more orientationally disordered in comparison with that of a trans conformer. Comparing nematic and smectic LCEs, actuation in the smectic phase proved less effective, disrupting the smectic layers to some extent but preserving orientational order of the azobenzene moieties.
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Affiliation(s)
- Gregor Skačej
- Faculty
of Mathematics and Physics, University of
Ljubljana, SI-1000 Ljubljana, Slovenia
| | - Lara Querciagrossa
- Dipartimento
di Chimica Industriale “Toso Montanari”, Università di Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy
- CINECA, Via Magnanelli 6/3, I-40033 Casalecchio di Reno, Italy
| | - Claudio Zannoni
- Dipartimento
di Chimica Industriale “Toso Montanari”, Università di Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy
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2
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Nemati A, Querciagrossa L, Callison C, Shadpour S, Nunes Gonçalves DP, Mori T, Cui X, Ai R, Wang J, Zannoni C, Hegmann T. Effects of shape and solute-solvent compatibility on the efficacy of chirality transfer: Nanoshapes in nematics. Sci Adv 2022; 8:eabl4385. [PMID: 35080976 PMCID: PMC8791610 DOI: 10.1126/sciadv.abl4385] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Chirality, as a concept, is well understood at most length scales. However, quantitative models predicting the efficacy of the transmission of chirality across length scales are lacking. We propose here a modus operandi for a chiral nanoshape solute in an achiral nematic liquid crystal host showing that that chirality transfer may be understood by unusually simple geometric considerations. This mechanism is based on the product of a pseudoscalar chirality indicator and of a geometric shape compatibility factor based on the two-dimensional isoperimetric quotients for each nanoshape solute. The model is tested on an experimental set of precisely engineered gold nanoshapes. These libraries of calculated and in-parallel acquired experimental data among related nanoshapes pave the way for predictive calculations of chirality transfer in nanoscale, macromolecular, and biological systems, from designing chiral discriminators and enantioselective catalysts to developing chiral metamaterials and understanding nature's innate ability to transfer homochirality across length scales.
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Affiliation(s)
- Ahlam Nemati
- Materials Science Graduate Program, Kent State University, Kent, OH, USA
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH, USA
| | - Lara Querciagrossa
- Dipartimento di Chimica Industriale and INSTM, Università di Bologna, Bologna, Italy
| | - Corinne Callison
- Materials Science Graduate Program, Kent State University, Kent, OH, USA
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH, USA
| | - Sasan Shadpour
- Materials Science Graduate Program, Kent State University, Kent, OH, USA
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH, USA
| | | | - Taizo Mori
- Institute for Solid State Physics, The University of Tokyo, Tokyo, Japan
| | - Ximin Cui
- Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Ruoqi Ai
- Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Jianfang Wang
- Department of Physics, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China
| | - Claudio Zannoni
- Dipartimento di Chimica Industriale and INSTM, Università di Bologna, Bologna, Italy
- Corresponding author. (C.Z.); (T.H.)
| | - Torsten Hegmann
- Materials Science Graduate Program, Kent State University, Kent, OH, USA
- Advanced Materials and Liquid Crystal Institute, Kent State University, Kent, OH, USA
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH, USA
- Brain Health Research Institute, Kent State University, Kent, OH, USA
- Corresponding author. (C.Z.); (T.H.)
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3
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Skačej G, Zannoni C. The nematic-isotropic transition of the Lebwohl-Lasher model revisited. Philos Trans A Math Phys Eng Sci 2021; 379:20200117. [PMID: 34024130 DOI: 10.1098/rsta.2020.0117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 10/12/2020] [Indexed: 06/12/2023]
Abstract
We revisited the nematic-isotropic (NI) transition of the Lebwohl-Lasher lattice model with a detailed investigation of samples containing 200 × 200 × 200 particles. The large-scale Monte Carlo (MC) simulations involved were carried out following the standard Metropolis, as well as the cluster MC Wolff algorithms. A notable free-energy barrier was observed between the isotropic and nematic phase, leading to long-lived metastable states and hysteresis. We provide an improved estimate of the nematic-isotropic transition temperature TNI, of the supercooling and superheating temperatures, of the temperature of divergence of pretransitional effects [Formula: see text] as well as an analysis of the size distribution of the ordered domains above TNI, contributing to a better understanding of this transition of key importance for liquid crystals. This article is part of the theme issue 'Topics in mathematical design of complex materials'.
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Affiliation(s)
- Gregor Skačej
- Faculty of Mathematics and Physics, University of Ljubljana, Jadranska, 19, SI-1000 Ljubljana, Slovenia
| | - Claudio Zannoni
- Dipartimento di Chimica Industriale 'Toso Montanari' and INSTM, Università di Bologna, Viale Risorgimento, 4, I-40136 Bologna, Italy
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4
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Chen X, Fonseca I, Ravnik M, Slastikov V, Zannoni C, Zarnescu A. Topics in the mathematical design of materials. Philos Trans A Math Phys Eng Sci 2021; 379:20200108. [PMID: 34024134 DOI: 10.1098/rsta.2020.0108] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 03/29/2021] [Indexed: 06/12/2023]
Abstract
We present a perspective on several current research directions relevant to the mathematical design of new materials. We discuss: (i) design problems for phase-transforming and shape-morphing materials, (ii) epitaxy as an approach of central importance in the design of advanced semiconductor materials, (iii) selected design problems in soft matter, (iv) mathematical problems in magnetic materials, (v) some open problems in liquid crystals and soft materials and (vi) mathematical problems on liquid crystal colloids. The presentation combines topics from soft and hard condensed matter, with specific focus on those design themes where mathematical approaches could possibly lead to exciting progress. This article is part of the theme issue 'Topics in mathematical design of complex materials'.
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Affiliation(s)
- Xian Chen
- Department of Mechanical and Aerospace Engineering, Hong Kong University of Science and Technology, Pokfulam, Hong Kong
| | - Irene Fonseca
- Carnegie Mellon University, 5000 Forbes Avenue, Pittsburgh, PA 15213, USA
| | - Miha Ravnik
- University of Ljubljana, Jadranska, 19, 1000 Ljubljana, Slovenia
- Jozef Stefan Insitute, Jamova cesta, 39, 1000 Ljubljana, Slovenia
| | | | - Claudio Zannoni
- Dipartimento di Chimica Industriale 'Toso Montanari' and INSTM, Università di Bologna, Viale Risorgimento, 4, 40136 Bologna, Italy
| | - Arghir Zarnescu
- BCAM, Basque Center for Applied Mathematics, Alameda Mazarredo, 14 Bilbao 48009, Spain
- IKERBASQUE, Basque Foundation for Science, Plaza Euskadi, 5 48009 Bilbao, Bizkaia, Spain
- 'Simion Stoilow' Institute of the Romanian Academy, 21 Calea Grivitei, 010702 Bucharest, Romania
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5
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Chiccoli C, Pasini P, Evangelista LR, Skačej G, de Souza RT, Zannoni C. Elastic constants and the formation of topological defects in hybrid nematic cells: A Monte Carlo study. Phys Rev E 2020; 102:042702. [PMID: 33212651 DOI: 10.1103/physreve.102.042702] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Accepted: 10/02/2020] [Indexed: 11/07/2022]
Abstract
We present a Monte Carlo study of the effects of elastic anisotropy on the topological defects which can be formed in nematic films with hybrid boundary conditions. We simulate the polarized microscopy images and analyze their evolution in uniaxial systems for different values of the Frank elastic constants.
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Affiliation(s)
- Cesare Chiccoli
- INFN, Sezione di Bologna, Via Irnerio 46, I-40126 Bologna, Italy
| | - Paolo Pasini
- INFN, Sezione di Bologna, Via Irnerio 46, I-40126 Bologna, Italy
| | - Luiz Roberto Evangelista
- Departamento de Física, Universidade Estadual de Maringá, Avenida Colombo, 5790-87020-900 Maringá (PR), Brazil
| | - Gregor Skačej
- Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, SI-1000 Ljubljana, Slovenia
| | - Rodolfo Teixeira de Souza
- Departamento Acadêmico de Física, Universidade Tecnológica Federal do Paraná, Campus Apucarana, Rua Marcílio Dias, 635 CEP 86812-460 - Apucarana (PR), Brazil
| | - Claudio Zannoni
- Dipartimento di Chimica Industriale "Toso Montanari" and INSTM, Università di Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy
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6
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Ricci M, Roscioni OM, Querciagrossa L, Zannoni C. MOLC. A reversible coarse grained approach using anisotropic beads for the modelling of organic functional materials. Phys Chem Chem Phys 2019; 21:26195-26211. [PMID: 31755499 DOI: 10.1039/c9cp04120f] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
We describe the development and implementation of a coarse grained (CG) modelling approach where complex organic molecules, and particularly the π-conjugated ones often employed in organic electronics, are modelled in terms of connected sets of attractive-repulsive biaxial Gay-Berne ellipsoidal beads. The CG model is aimed at reproducing realistically large scale morphologies (e.g. up to 100 nm thick films) for the materials involved, while being able to generate, with a back-mapping procedure, atomistic coordinates suitable, with limited effort, to be applied for charge transport calculations. Detailed methodology and an application to the common hole transporter material α-NPD are provided.
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Affiliation(s)
- Matteo Ricci
- Dipartimento di Chimica Industriale "Toso Montanari" and INSTM, Università di Bologna, Viale Risorgimento 4, IT-40136 Bologna, Italy.
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7
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Chiccoli C, Evangelista LR, Pasini P, Skačej G, de Souza RT, Zannoni C. Influence of boundary conditions on the order and defects of biaxial nematic droplets. Phys Rev E 2019; 100:032702. [PMID: 31639958 DOI: 10.1103/physreve.100.032702] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Indexed: 11/07/2022]
Abstract
We employ Monte Carlo simulations to study the defects occurring in a nematic droplet formed by biaxial molecules. The simulations are carried out using a lattice model based on a dispersive orientational biaxial potential previously employed to establish the rich phase diagram of the system. The focus of the present investigation is on the molecular organization inside the droplet when bipolar and toroidal anchoring conditions at the surface are considered. In both cases, we describe how the defect structure arises in the system, and we analyze the behavior of the defect core region in connection with the elastic properties of the phase in a continuum theory perspective.
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Affiliation(s)
- C Chiccoli
- INFN Sezione di Bologna, Via Irnerio 46, 40126 Bologna, Italy
| | - L R Evangelista
- Departamento de Física, Universidade Estadual de Maringá, Avenida Colombo 5790, 87020-900, Maringá, Paraná, Brazil.,Dipartimento di Scienza Applicata del Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129 Torino, Italy
| | - P Pasini
- INFN Sezione di Bologna, Via Irnerio 46, 40126 Bologna, Italy
| | - G Skačej
- Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, SI-1000 Ljubljana, Slovenia
| | - R Teixeira de Souza
- Departamento de Física, Universidade Estadual de Maringá, Avenida Colombo 5790, 87020-900, Maringá, Paraná, Brazil.,Departamento Acadêmico de Física, Universidade Tecnológica Federal do Paraná, Campus Apucarana, Rua Marcílio Dias, 635 CEP 86812-460-Apucarana, Paraná, Brazil
| | - C Zannoni
- Dipartimento di Chimica Industriale "Toso Montanari," Università di Bologna and INSTM, Viale Risorgimento 4, I-40136 Bologna, Italy
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8
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Aleotti F, Soprani L, Nenov A, Berardi R, Arcioni A, Zannoni C, Garavelli M. Multidimensional Potential Energy Surfaces Resolved at the RASPT2 Level for Accurate Photoinduced Isomerization Dynamics of Azobenzene. J Chem Theory Comput 2019; 15:6813-6823. [DOI: 10.1021/acs.jctc.9b00561] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Affiliation(s)
- Flavia Aleotti
- Dipartimento di Chimica Industriale “Toso Montanari”, Universitá di Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy
| | - Lorenzo Soprani
- Dipartimento di Chimica Industriale “Toso Montanari”, Universitá di Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy
| | - Artur Nenov
- Dipartimento di Chimica Industriale “Toso Montanari”, Universitá di Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy
| | - Roberto Berardi
- Dipartimento di Chimica Industriale “Toso Montanari”, Universitá di Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy
| | - Alberto Arcioni
- Dipartimento di Chimica Industriale “Toso Montanari”, Universitá di Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy
| | - Claudio Zannoni
- Dipartimento di Chimica Industriale “Toso Montanari”, Universitá di Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy
| | - Marco Garavelli
- Dipartimento di Chimica Industriale “Toso Montanari”, Universitá di Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy
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9
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Vieira da Silva B, Yednak C, Chiccoli C, Pasini P, Evangelista L, Teixeira de Souza R, Zannoni C. Analytical and computer simulation study of molecular ordering of a liquid-crystalline system in annular confinements. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.111324] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Nemati A, Shadpour S, Querciagrossa L, Mori T, Zannoni C, Hegmann T. Highly Sensitive, Tunable Chirality Amplification through Space Visualized for Gold Nanorods Capped with Axially Chiral Binaphthyl Derivatives. ACS Nano 2019; 13:10312-10326. [PMID: 31424907 DOI: 10.1021/acsnano.9b03787] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The creation and transmission of chirality in molecular systems is a well-known, widely applied notion. Our understanding of how the chirality of nanomaterials can be controlled, measured, transmitted through space, and applied is less well understood. Dynamic assemblies for chiral sensing or metamaterials engineered from chiral nanomaterials require exact methods to determine transmission and amplification of nanomaterial chirality through space. We report the synthesis of a series of gold nanorods (GNRs) with a constant aspect ratio of ∼4.3 capped with C2-symmetric, axially chiral binaphthyl thiols, preparation of dispersions in the nematic liquid crystal 5CB, measurements of the helical pitch, and the determination of the helical twisting power as well as the average distance between the chiral nanomaterial additives. By comparison to the neat organic chiral derivatives, we demonstrate how the amplification of chirality facilitated by GNRs decorated with chiral molecules can be used to clearly distinguish the chiral induction strength of a homologous series of binaphthyl derivatives, differing only in the length of the nontethered aliphatic chain, in the induced chiral nematic liquid crystal phase. Considering systematic errors in sample preparation and optical measurements, these chiral molecules would otherwise be deemed identical with respect to chiral induction. Notably, we find some of the highest ever-reported values of the helical twisting power. We further support our experimentally derived arguments of a more comprehensive understanding of chirality transfer by calculations of a suitable pseudoscalar chirality indicator.
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Affiliation(s)
- Ahlam Nemati
- Advanced Materials and Liquid Crystal Institute, Chemical Physics Interdisciplinary Program , Kent State University , Kent , Ohio 44242 , United States
| | - Sasan Shadpour
- Advanced Materials and Liquid Crystal Institute, Chemical Physics Interdisciplinary Program , Kent State University , Kent , Ohio 44242 , United States
| | - Lara Querciagrossa
- Dipartimento di Chimica Industriale "Toso Montanari" and INSTM , Università di Bologna , Viale Risorgimento 4 , IT-40136 Bologna , Italy
| | - Taizo Mori
- Graduate School of Frontier Science , The University of Tokyo , 5-1-5, Kashiwanoha , Kashiwa 277-0827 , Japan
| | - Claudio Zannoni
- Dipartimento di Chimica Industriale "Toso Montanari" and INSTM , Università di Bologna , Viale Risorgimento 4 , IT-40136 Bologna , Italy
| | - Torsten Hegmann
- Advanced Materials and Liquid Crystal Institute, Chemical Physics Interdisciplinary Program , Kent State University , Kent , Ohio 44242 , United States
- Department of Chemistry and Biochemistry , Kent State University , Kent , Ohio 44242 , United States
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11
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Almeida APC, Querciagrossa L, Silva PES, Gonçalves F, Canejo JP, Almeida PL, Godinho MH, Zannoni C. Reversible water driven chirality inversion in cellulose-based helices isolated from Erodium awns. Soft Matter 2019; 15:2838-2847. [PMID: 30869683 DOI: 10.1039/c8sm02290a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Among the movements observed in some cellulosic structures produced by plants are those that involve the dispersion and burial of seeds, as for example in Erodium from the Geraniaceae plant family. Here we report on a simple and efficient strategy to isolate and tune cellulose-based hygroscopic responsive materials from Erodium awns' dead tissues. The stimuli-responsive material isolated forms left-handed (L) or right-handed (R) helical birefringent transparent ribbons in the wet state that reversibly change to R helices when the material dries. The humidity-driven motion of dead tissues is most likely due to a composite material made of cellulose networks of fibrils imprinted by the plant at the nanoscale, which reinforces a soft wall polysaccharide matrix. The inversion of the handedness is explained using computational simulations considering filaments that contract and expand asymmetrically. The awns of Erodium are known to present hygroscopic movements, forming R helices in the dry state, but the possibility of actuating chirality via humidity suggests that these cellulose-based skeletons, which do not require complicated lithography and intricate deposition techniques, provide a diverse range of applications from intelligent textiles to micro-machines.
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Affiliation(s)
- Ana P C Almeida
- CENIMAT/I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, FCT, Universidade NOVA de Lisboa, Campus da Caparica, 2829-516 Caparica, Portugal.
| | - Lara Querciagrossa
- Dipartimento di Chimica Industriale "Toso Montanari" and INSTM, Università di Bologna, Viale Risorgimento 4, IT-40136 Bologna, Italy.
| | - Pedro E S Silva
- CENIMAT/I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, FCT, Universidade NOVA de Lisboa, Campus da Caparica, 2829-516 Caparica, Portugal.
| | - Filipa Gonçalves
- CENIMAT/I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, FCT, Universidade NOVA de Lisboa, Campus da Caparica, 2829-516 Caparica, Portugal.
| | - João P Canejo
- CENIMAT/I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, FCT, Universidade NOVA de Lisboa, Campus da Caparica, 2829-516 Caparica, Portugal.
| | - Pedro L Almeida
- CENIMAT/I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, FCT, Universidade NOVA de Lisboa, Campus da Caparica, 2829-516 Caparica, Portugal. and Área Departamental de Física, Instituto Superior de Engenharia de Lisboa, Instituto Politécnico de Lisboa, 1959-007 Lisbon, Portugal
| | - Maria Helena Godinho
- CENIMAT/I3N, Departamento de Ciência dos Materiais, Faculdade de Ciências e Tecnologia, FCT, Universidade NOVA de Lisboa, Campus da Caparica, 2829-516 Caparica, Portugal.
| | - Claudio Zannoni
- Dipartimento di Chimica Industriale "Toso Montanari" and INSTM, Università di Bologna, Viale Risorgimento 4, IT-40136 Bologna, Italy.
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12
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Roscioni OM, D'Avino G, Muccioli L, Zannoni C. Pentacene Crystal Growth on Silica and Layer-Dependent Step-Edge Barrier from Atomistic Simulations. J Phys Chem Lett 2018; 9:6900-6906. [PMID: 30449102 DOI: 10.1021/acs.jpclett.8b03063] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Understanding and controlling the growth of organic crystals deposited from the vapor phase is important for fundamental materials science and necessary for applications in pharmaceutical and organic electronics industries. Here, this process is studied for the paradigmatic case of pentacene on silica by means of a specifically tailored computational approach inspired by the experimental vapor deposition process. This scheme is able to reproduce the early stages of the thin-film formation, characterized by a quasi layer-by-layer growth, thus showcasing its potential as a tool complementary to experimental techniques for investigating organic crystals. Crystalline islands of standing molecules are formed at a critical coverage, as a result of a collective reorientation of disordered aggregates of flat-lying molecules. The growth then proceeds by sequential attachment of molecules at the cluster and then terrace edges. Free-energy calculations allowed us to characterize the step-edge barrier for descending the terraces, a fundamental parameter for growth models for which only indirect experimental measurements are available. The barrier is found to be layer-dependent (approximately 1 kcal/mol for the first monolayer on silica, 2 kcal/mol for the second monolayer) and to extend over a distance comparable with the molecular length.
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Affiliation(s)
- Otello Maria Roscioni
- Dipartimento di Chimica Industriale "Toso Montanari" , University of Bologna , Viale Risorgimento 4 , I-40136 Bologna , Italy
| | - Gabriele D'Avino
- Institut Néel, CNRS and Grenoble Alpes University , 25 Rue des Martyrs , F-38042 Grenoble , France
| | - Luca Muccioli
- Dipartimento di Chimica Industriale "Toso Montanari" , University of Bologna , Viale Risorgimento 4 , I-40136 Bologna , Italy
| | - Claudio Zannoni
- Dipartimento di Chimica Industriale "Toso Montanari" , University of Bologna , Viale Risorgimento 4 , I-40136 Bologna , Italy
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13
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Chiccoli C, Pasini P, Zannoni C. Can elastic constants and surface alignment be obtained from polarized microscopy images of nematic droplets? A Monte Carlo study. J Mol Liq 2018. [DOI: 10.1016/j.molliq.2017.12.045] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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14
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Nemati A, Shadpour S, Querciagrossa L, Li L, Mori T, Gao M, Zannoni C, Hegmann T. Chirality amplification by desymmetrization of chiral ligand-capped nanoparticles to nanorods quantified in soft condensed matter. Nat Commun 2018; 9:3908. [PMID: 30254259 PMCID: PMC6156227 DOI: 10.1038/s41467-018-06400-0] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2018] [Accepted: 08/29/2018] [Indexed: 11/13/2022] Open
Abstract
Induction, transmission, and manipulation of chirality in molecular systems are well known, widely applied concepts. However, our understanding of how chirality of nanoscale entities can be controlled, measured, and transmitted to the environment is considerably lacking behind. Future discoveries of dynamic assemblies engineered from chiral nanomaterials, with a specific focus on shape and size effects, require exact methods to assess transmission and amplification of nanoscale chirality through space. Here we present a remarkably powerful chirality amplification approach by desymmetrization of plasmonic nanoparticles to nanorods. When bound to gold nanorods, a one order of magnitude lower number of chiral molecules induces a tighter helical distortion in the surrounding liquid crystal-a remarkable amplification of chirality through space. The change in helical distortion is consistent with a quantification of the change in overall chirality of the chiral ligand decorated nanomaterials differing in shape and size as calculated from a suitable pseudoscalar chirality indicator.
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Affiliation(s)
- Ahlam Nemati
- Chemical Physics Interdisciplinary Program, Liquid Crystal Institute, Kent State University, Kent, OH, 44242-0001, USA
| | - Sasan Shadpour
- Chemical Physics Interdisciplinary Program, Liquid Crystal Institute, Kent State University, Kent, OH, 44242-0001, USA
| | - Lara Querciagrossa
- Dipartimento di Chimica Industriale "Toso Montanari" and INSTM, Università di Bologna, Viale Risorgimento 4, IT-40136, Bologna, Italy
| | - Lin Li
- Institute for Smart Liquid Crystals, JITRI, Changshu, 215500, Jiangsu, China
| | - Taizo Mori
- Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), 1-1 Namiki, Tsukuba, Ibaraki, 305-0044, Japan
| | - Min Gao
- Chemical Physics Interdisciplinary Program, Liquid Crystal Institute, Kent State University, Kent, OH, 44242-0001, USA
| | - Claudio Zannoni
- Dipartimento di Chimica Industriale "Toso Montanari" and INSTM, Università di Bologna, Viale Risorgimento 4, IT-40136, Bologna, Italy
| | - Torsten Hegmann
- Chemical Physics Interdisciplinary Program, Liquid Crystal Institute, Kent State University, Kent, OH, 44242-0001, USA.
- Department of Chemistry and Biochemistry, Kent State University, Kent, OH, 44242-0001, USA.
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15
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Abstract
We have studied liquid crystal phases formed by fullerenes functionalized with mesogenic groups yielding a cone-shaped molecular structure. We have modelled these shuttlecock-like molecules with a set of Gay-Berne particles grafted with flexible springs to a spherical core and we have studied, using Monte Carlo simulations, their phase organization, also with a view to examining their possible use as candidate organic photovoltaic materials. We have found that, upon cooling from the isotropic phase, the system forms a columnar phase, like in the experimental work of Kato and coworkers [T. Kato et al., Nature, 2002, 419, 702]. However the phase is made of polar stacks extending not more than about ten molecules, which could limit their usefulness in enhancing and directing charge transport for possible photovoltaic applications.
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Affiliation(s)
- Silvia Orlandi
- Dipartimento di Chimica Industriale "Toso Montanari" and INSTM, Università di Bologna, Viale Risorgimento 4, IT-40136 Bologna, Italy.
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16
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Abstract
We have investigated the possibility of extending the stability range of the biaxial nematic phase by adding an off-centre dipole of various strengths and orientations to elongated biaxial Gay-Berne (GB) mesogens yielding a relatively narrow biaxial nematic (Nbx) phase, and a smectic (Sbx) phase when dipole-less. The effect of dipoles is not easy to predict, and our previous investigations have shown the limited benefits of having a central dipole. Here we show, employing molecular dynamics (MD) simulations, that a not too strong off-centre dipole positioned along the longest axis of the nematogen can extend the temperature range of stability of the biaxial nematic phase, also shifting it towards lower temperatures.
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Affiliation(s)
- Lara Querciagrossa
- Dipartimento di Chimica Industriale "Toso Montanari" and INSTM, Università di Bologna, Viale Risorgimento 4, IT-40136 Bologna, Italy.
| | - Roberto Berardi
- Dipartimento di Chimica Industriale "Toso Montanari" and INSTM, Università di Bologna, Viale Risorgimento 4, IT-40136 Bologna, Italy.
| | - Claudio Zannoni
- Dipartimento di Chimica Industriale "Toso Montanari" and INSTM, Università di Bologna, Viale Risorgimento 4, IT-40136 Bologna, Italy.
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17
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Chiccoli C, Evangelista LR, Pasini P, Skačej G, Teixeira de Souza R, Zannoni C. On the Defect Structure of Biaxial Nematic Droplets. Sci Rep 2018; 8:2130. [PMID: 29391472 PMCID: PMC5794765 DOI: 10.1038/s41598-018-20492-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2017] [Accepted: 01/12/2018] [Indexed: 11/12/2022] Open
Abstract
We present a detailed Monte Carlo study of the effects of molecular biaxiality on the defect created at the centre of a nematic droplet with radial anchoring at the surface. We have studied a lattice model based on a dispersive potential for biaxial mesogens [Luckhurst et al., Mol. Phys. 30, 1345 (1975)] to investigate how increasing the biaxiality influences the molecular organisation inside the confined system. The results are compared with those obtained from a continuum theory approach. We find from both approaches that the defect core size increases by increasing the molecular biaxiality, hinting at a non universal behaviour previously not reported.
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Affiliation(s)
- C Chiccoli
- INFN Sezione di Bologna, Via Irnerio 46, 40126, Bologna, Italy
| | - L R Evangelista
- Departamento de Física, Universidade Estadual de Maringá, Avenida Colombo, 5790-87020-900, Maringá, Paraná, Brazil.
| | - P Pasini
- INFN Sezione di Bologna, Via Irnerio 46, 40126, Bologna, Italy
| | - G Skačej
- Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, SI-1000, Ljubljana, Slovenia
| | - R Teixeira de Souza
- Departamento Acadêmico de Física, Universidade Tecnológica Federal do Paraná, Campus Apucarana, Rua Marcílio Dias, 635 CEP 86812-460, Apucarana, Paraná, Brazil
| | - C Zannoni
- Dipartimento di Chimica Industriale "Toso Montanari", Università di Bologna and INSTM, Viale Risorgimento 4, I-40136, Bologna, Italy
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18
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Gali SM, D’Avino G, Aurel P, Han G, Yi Y, Papadopoulos TA, Coropceanu V, Brédas JL, Hadziioannou G, Zannoni C, Muccioli L. Energetic fluctuations in amorphous semiconducting polymers: Impact on charge-carrier mobility. J Chem Phys 2017; 147:134904. [DOI: 10.1063/1.4996969] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Sai Manoj Gali
- Institut des Sciences Moléculaires, UMR 5255, University of Bordeaux, Talence, France
- Laboratoire de Chimie des Polymères Organiques, UMR 5629, University of Bordeaux, Pessac, France
| | - Gabriele D’Avino
- Institut Néel, CNRS and Grenoble Alpes University, Grenoble, France
| | - Philippe Aurel
- Institut des Sciences Moléculaires, UMR 5255, University of Bordeaux, Talence, France
| | - Guangchao Han
- Institute of Chemistry, Chinese Academy of Sciences, Beijing, China
| | - Yuanping Yi
- Institute of Chemistry, Chinese Academy of Sciences, Beijing, China
| | | | - Veaceslav Coropceanu
- Center for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Jean-Luc Brédas
- Center for Organic Photonics and Electronics, Georgia Institute of Technology, Atlanta, Georgia 30332, USA
| | - Georges Hadziioannou
- Laboratoire de Chimie des Polymères Organiques, UMR 5629, University of Bordeaux, Pessac, France
| | - Claudio Zannoni
- Dipartimento di Chimica Industriale “Toso Montanari,” University of Bologna, Bologna, Italy
| | - Luca Muccioli
- Institut des Sciences Moléculaires, UMR 5255, University of Bordeaux, Talence, France
- Dipartimento di Chimica Industriale “Toso Montanari,” University of Bologna, Bologna, Italy
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19
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Roscioni OM, Muccioli L, Zannoni C. Predicting the Conditions for Homeotropic Anchoring of Liquid Crystals at a Soft Surface. 4-n-Pentyl-4'-cyanobiphenyl on Alkylsilane Self-Assembled Monolayers. ACS Appl Mater Interfaces 2017; 9:11993-12002. [PMID: 28287693 DOI: 10.1021/acsami.6b16438] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
We have studied, using atomistic molecular dynamics simulations, the alignment of the nematic liquid-crystal 4-n-pentyl-4'-cyanobiphenyl (5CB) on self-assembled monolayers (SAMs) formed from octadecyl- and/or hexyltrichlorosilane (OTS and HTS) attached to glassy silica. We find a planar alignment on OTS at full coverage and an intermediate situation at partial OTS coverage because of the penetration of 5CB molecules into the monolayer, which also removes the tilt of the OTS SAM. Binary mixtures of HTS and OTS SAMs instead induce homeotropic (i.e., perpendicular) alignment. A comparison with the existing experimental literature is provided.
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Affiliation(s)
- Otello Maria Roscioni
- Dipartimento di Chimica Industriale "Toso Montanari" Università di Bologna , viale Risorgimento 4, IT-40136 Bologna, Italy
| | - Luca Muccioli
- Dipartimento di Chimica Industriale "Toso Montanari" Università di Bologna , viale Risorgimento 4, IT-40136 Bologna, Italy
| | - Claudio Zannoni
- Dipartimento di Chimica Industriale "Toso Montanari" Università di Bologna , viale Risorgimento 4, IT-40136 Bologna, Italy
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20
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Abstract
The theory of rotational diffusion of particles of various symmetry embedded in a liquid crystal host, essential to interpret a variety of spectroscopic observables, has been available for some time, but only for the case of rigid molecules. Here we generalize the treatment and present a theory to describe the rotational diffusion of shape-changing particles dispersed in nematic liquid crystals. The interaction of the particles with the environment is modeled by an effective field potential, while the particles are allowed to assume an arbitrary discrete number of shapes. The transition between shapes is modeled by a Markovian process which is combined with rotational diffusion. Our model is applied to the simple case of a particle that can exchange between three shapes: a rod, a disk, and a sphere. We consider in detail the effect of shape transitions in some selected correlation functions which are relevant for experiments.
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Affiliation(s)
- R F de Souza
- Dipartimento di Chimica Industriale "Toso Montanari" and INSTM, Università di Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy.,CAPES Foundation, Ministry of Education of Brazil, Brasília, DF 70040-020, Brazil
| | - C Zannoni
- Dipartimento di Chimica Industriale "Toso Montanari" and INSTM, Università di Bologna, Viale del Risorgimento 4, 40136 Bologna, Italy
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21
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Querciagrossa L, Ricci M, Berardi R, Zannoni C. Can multi-biaxial mesogenic mixtures favour biaxial nematics? A computer simulation study. Phys Chem Chem Phys 2017; 19:2383-2391. [DOI: 10.1039/c6cp05117k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A mixture of mesogens with different anisotropies favours the biaxial nematic phase.
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Affiliation(s)
- Lara Querciagrossa
- Department of Industrial Chemistry “Toso Montanari”
- University of Bologna
- 40136 Bologna
- Italy
| | - Matteo Ricci
- Department of Industrial Chemistry “Toso Montanari”
- University of Bologna
- 40136 Bologna
- Italy
| | - Roberto Berardi
- Department of Industrial Chemistry “Toso Montanari”
- University of Bologna
- 40136 Bologna
- Italy
| | - Claudio Zannoni
- Department of Industrial Chemistry “Toso Montanari”
- University of Bologna
- 40136 Bologna
- Italy
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22
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Abstract
The performance of devices based on organic semiconductors strongly depends on the molecular organisation in thin films. Due to the intrinsic complexity of these systems, a combination of theoretical modelling and experimental techniques is often the key to achieve a full understanding of their inner working. Here, we introduce the modelling of organic semiconductors by means of molecular dynamics simulations. We describe the basic theoretical framework of the technique and review the most popular class of force fields used to model organic materials, paying particular attention to the peculiarities of confined systems like nano-thick films. Representative studies of the organisation of organic functional materials in thin film phases are also reviewed.
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Affiliation(s)
- Otello Maria Roscioni
- Dipartimento di Chimica Industriale “Toso Montanari”, Università di Bologna viale Risorgimento 4 40136 Bologna Italy
| | - Claudio Zannoni
- Dipartimento di Chimica Industriale “Toso Montanari”, Università di Bologna viale Risorgimento 4 40136 Bologna Italy
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23
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Vanzo D, Ricci M, Berardi R, Zannoni C. Wetting behaviour and contact angles anisotropy of nematic nanodroplets on flat surfaces. Soft Matter 2016; 12:1610-1620. [PMID: 26670582 DOI: 10.1039/c5sm02179k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
We have studied the wetting behaviour of liquid crystal nanodroplets deposited on a planar surface, modelling the mesogens with Gay-Berne ellipsoids and the support surface with a slab of Lennard-Jones (LJ) spherical particles whose mesogen-surface affinity can be tuned. A crystalline and an amorphous planar surface, both showing planar anchoring, have been investigated: the first is the (001) facet of a LJ fcc crystal, the second is obtained from a disordered LJ glass. In both cases we find that the deposited nanodroplet is, in general, elongated and that the contact angle changes around its contour. Simulations for the crystalline substrate show that the angle of contact turns reversibly from anisotropic to isotropic when crossing the clearing transition. As far as we know this is a novel, not yet explored effect for thermotropic liquid crystals, that we hope will stimulate experimental investigations.
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Affiliation(s)
- Davide Vanzo
- Department of Industrial Chemistry "Toso Montanari", University of Bologna, viale Risorgimento 4, 40136 Bologna, Italy.
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24
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Orlandi S, Benini E, Miglioli I, Evans DR, Reshetnyak V, Zannoni C. Doping liquid crystals with nanoparticles. A computer simulation of the effects of nanoparticle shape. Phys Chem Chem Phys 2016; 18:2428-41. [DOI: 10.1039/c5cp05754j] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Molecular-scale Monte Carlo simulations of liquid crystal-nanoparticle dispersions show the effect on the orientational order and on the clearing temperature of shape and concentration of the dopant nanoparticles.
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Affiliation(s)
- Silvia Orlandi
- Dipartimento di Chimica Industriale “Toso Montanari” and INSTM
- Università di Bologna
- IT-40136 Bologna
- Italy
| | - Erika Benini
- Dipartimento di Chimica Industriale “Toso Montanari” and INSTM
- Università di Bologna
- IT-40136 Bologna
- Italy
| | - Isabella Miglioli
- Dipartimento di Chimica Industriale “Toso Montanari” and INSTM
- Università di Bologna
- IT-40136 Bologna
- Italy
| | - Dean R. Evans
- Air Force Research Laboratory
- Materials and Manufacturing Directorate
- Ohio 45433
- USA
| | | | - Claudio Zannoni
- Dipartimento di Chimica Industriale “Toso Montanari” and INSTM
- Università di Bologna
- IT-40136 Bologna
- Italy
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25
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Velayutham TS, Nguan HS, Ng BK, Gan WC, Manickam Achari V, Zahid NI, Abd. Majid WH, Zannoni C, Hashim R. Molecular dynamics of anhydrous glycolipid self-assembly in lamellar and hexagonal phases. Phys Chem Chem Phys 2016; 18:15182-90. [DOI: 10.1039/c6cp00583g] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The molecular dynamics of a synthetic branched chain glycolipid, 2-decyl-tetradecyl-β-d-maltoside (C14-10G2), in smectic and columnar liquid crystal phases.
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Affiliation(s)
- T. S. Velayutham
- Low Dimensional Materials Research Center
- Faculty of Science
- University Malaya
- 50603 Kuala Lumpur
- Malaysia
| | - H. S. Nguan
- Fundamental and Frontier Science of Self-Assembly Center
- Faculty of Science
- University Malaya
- 50603 Kuala Lumpur
- Malaysia
| | - B. K. Ng
- Low Dimensional Materials Research Center
- Faculty of Science
- University Malaya
- 50603 Kuala Lumpur
- Malaysia
| | - W. C. Gan
- Low Dimensional Materials Research Center
- Faculty of Science
- University Malaya
- 50603 Kuala Lumpur
- Malaysia
| | - V. Manickam Achari
- Fundamental and Frontier Science of Self-Assembly Center
- Faculty of Science
- University Malaya
- 50603 Kuala Lumpur
- Malaysia
| | - N. I. Zahid
- Fundamental and Frontier Science of Self-Assembly Center
- Faculty of Science
- University Malaya
- 50603 Kuala Lumpur
- Malaysia
| | - W. H. Abd. Majid
- Low Dimensional Materials Research Center
- Faculty of Science
- University Malaya
- 50603 Kuala Lumpur
- Malaysia
| | - C. Zannoni
- Dipartimento di Chimica Industriale “Toso Montanari” viale Risorgimento 4 Universita' di Bologna
- 40136 Bologna
- Italy
| | - R. Hashim
- Fundamental and Frontier Science of Self-Assembly Center
- Faculty of Science
- University Malaya
- 50603 Kuala Lumpur
- Malaysia
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26
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Ricci M, Berardi R, Zannoni C. On the field-induced switching of molecular organization in a biaxial nematic cell and its relaxation. J Chem Phys 2015; 143:084705. [DOI: 10.1063/1.4928522] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Matteo Ricci
- Department of Industrial Chemistry “Toso Montanari,” University of Bologna, Viale Risorgimento 4, 40136 Bologna, Italy
| | - Roberto Berardi
- Department of Industrial Chemistry “Toso Montanari,” University of Bologna, Viale Risorgimento 4, 40136 Bologna, Italy
| | - Claudio Zannoni
- Department of Industrial Chemistry “Toso Montanari,” University of Bologna, Viale Risorgimento 4, 40136 Bologna, Italy
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27
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Weber ACJ, Burnell EE, Meerts WL, de Lange CA, Dong RY, Muccioli L, Pizzirusso A, Zannoni C. Communication: Molecular dynamics and 1H NMR of n-hexane in liquid crystals. J Chem Phys 2015; 143:011103. [DOI: 10.1063/1.4923253] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
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28
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Teixeira-Souza RT, Chiccoli C, Pasini P, Evangelista LR, Zannoni C. Nematic liquid crystals in planar and cylindrical hybrid cells: Role of elastic anisotropy on the director deformations. Phys Rev E Stat Nonlin Soft Matter Phys 2015; 92:012501. [PMID: 26274189 DOI: 10.1103/physreve.92.012501] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2015] [Indexed: 06/04/2023]
Abstract
Nematic samples filling a flat cell or the annular region between two concentric cylinders with hybrid anchoring conditions at the boundaries are investigated by setting up and minimizing their Frank elastic free energy. The coupling with the surfaces is taken to be strong on one side and weak on the other. The equations are numerically solved and the conditions for which the molecular organization inside the cell becomes uniform are analyzed. The classical calculation performed by G. Barbero and R. Barberi [J. Phys. 44, 609 (1983)] is reproduced and investigated from a different point of view, in order to compare the results of planar and cylindrical geometries. The results suggest that the cylindrical cell presents some unusual features deserving a more complete investigation. Although most part of the transitional phenomena are found for K(11)>K(33), a case not common for ordinary (lyotropic and thermotropic) liquid crystals, it is possible to find a completely uniform cell even for K(11)<K(33) in both the geometries considered here.
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Affiliation(s)
- R T Teixeira-Souza
- Universidade Tecnológica Federal do Paraná, Campus Apucarana, Rua Marcílio Dias 635, 86812-460 Apucarana, Paraná, Brazil
| | - C Chiccoli
- Istituto Nazionale di Fisica Nucleare, Sezione di Bologna, Via Irnerio 46, 40126 Bologna, Italy
| | - P Pasini
- Istituto Nazionale di Fisica Nucleare, Sezione di Bologna, Via Irnerio 46, 40126 Bologna, Italy
| | - L R Evangelista
- Departamento de Física, Universidade Estadual de Maringá, Avenida Colombo, 5790-87020-900 Maringá, Paraná, Brazil
| | - C Zannoni
- Dipartimento di Chimica Industriale "Toso Montanari" and INSTM, Università, Viale Risorgimento 4, 40136 Bologna, Italy
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29
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Chiccoli C, Pasini P, Evangelista LR, Teixeira-Souza RT, Zannoni C. Molecular organization of nematic liquid crystals between concentric cylinders: role of the elastic anisotropy. Phys Rev E Stat Nonlin Soft Matter Phys 2015; 91:022501. [PMID: 25768519 DOI: 10.1103/physreve.91.022501] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/14/2014] [Indexed: 06/04/2023]
Abstract
The orientational order in a nematic liquid crystal sample confined to an annular region between two concentric cylinders is investigated by means of lattice Monte Carlo simulations. Strong anchoring and homeotropic orientations, parallel to the radial direction, are implemented at the confining surfaces. The elastic anisotropy is taken into account in the bulk interactions by using the pair potential introduced by Gruhn and Hess [T. Gruhn and S. Hess, Z. Naturforsch. A 51, 1 (1996)] and parametrized by Romano and Luckhurst [S. Romano, Int. J. Mod. Phys. B 12, 2305 (1998); Phys. Lett. A 302, 203 (2002); G. R. Luckhurst and S. Romano, Liq. Cryst. 26, 871 (1999)], i.e., the so-called GHRL potential. In the case of equal elastic constants, a small but appreciable deformation along the cylinder axis direction is observed, whereas when the values of K(11)/K(33) if K(22)=K(33) are low enough, all the spins in the bulk follow the orientation imposed by the surfaces. For larger values of K(11)/K(33), spontaneous deformations, perpendicular to the polar plane, increase significantly. Our findings indicate that the onset of these deformations also depends on the ratio K(22)/K(33) and on the radius of the cylindrical surfaces. Although expected from the elastic theory, no tangential component of the deformations was observed in the simulations for the set of parameters analyzed.
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Affiliation(s)
- C Chiccoli
- Istituto Nazionale di Fisica Nucleare, Sezione di Bologna, Via Irnerio 46, 40126 Bologna, Italy
| | - P Pasini
- Istituto Nazionale di Fisica Nucleare, Sezione di Bologna, Via Irnerio 46, 40126 Bologna, Italy
| | - L R Evangelista
- Departamento de Física, Universidade Estadual de Maringá, Avenida Colombo, 5790-87020-900 Maringá, Paraná, Brazil
| | - R T Teixeira-Souza
- Universidade Tecnológica Federal do Paraná, Campus Apucarana, Rua Marcílio Dias 635, 86812-460 Apucarana, Paraná, Brazil
| | - C Zannoni
- Dipartimento di Chimica Industriale "Toso Montanari" and INSTM, Università di Bologna, Viale Risorgimento 4, 40136 Bologna, Italy
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30
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Palermo MF, Muccioli L, Zannoni C. Molecular organization in freely suspended nano-thick 8CB smectic films. An atomistic simulation. Phys Chem Chem Phys 2015; 17:26149-59. [DOI: 10.1039/c5cp04213e] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Atomistic simulations of nano-thick free 8CB smectic films show the change of order across the film with temperature and thickness.
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Affiliation(s)
- Mattia Felice Palermo
- Dipartimento di Chimica Industriale “Toso Montanari” and INSTM
- Università di Bologna
- IT-40136 Bologna
- Italy
| | - Luca Muccioli
- Dipartimento di Chimica Industriale “Toso Montanari” and INSTM
- Università di Bologna
- IT-40136 Bologna
- Italy
- Laboratoire de Chimie des Polymères Organiques
| | - Claudio Zannoni
- Dipartimento di Chimica Industriale “Toso Montanari” and INSTM
- Università di Bologna
- IT-40136 Bologna
- Italy
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31
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Affiliation(s)
- Gregor Skačej
- Faculty
of Mathematics and Physics, University of Ljubljana, Jadranska
19, SI-1000 Ljubljana, Slovenia
- NAMASTE Centre
of Excellence, Jamova 39, SI-1000 Ljubljana, Slovenia
| | - Claudio Zannoni
- Dipartimento
di Chimica Industriale “Toso Montanari” and INSTM, Università di Bologna, Viale Risorgimento 4, I-40136 Bologna, Italy
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32
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D’Avino G, Muccioli L, Zannoni C, Beljonne D, Soos ZG. Electronic Polarization in Organic Crystals: A Comparative Study of Induced Dipoles and Intramolecular Charge Redistribution Schemes. J Chem Theory Comput 2014; 10:4959-71. [DOI: 10.1021/ct500618w] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Affiliation(s)
- Gabriele D’Avino
- Department
of Industrial Chemistry “Toso Montanari” and INSTM, University of Bologna, Viale del Risorgimento 4, IT-40136 Bologna, Bologna, Italy
| | - Luca Muccioli
- Department
of Industrial Chemistry “Toso Montanari” and INSTM, University of Bologna, Viale del Risorgimento 4, IT-40136 Bologna, Bologna, Italy
| | - Claudio Zannoni
- Department
of Industrial Chemistry “Toso Montanari” and INSTM, University of Bologna, Viale del Risorgimento 4, IT-40136 Bologna, Bologna, Italy
| | - David Beljonne
- Laboratory
for Chemistry of Novel Materials, University of Mons, Place du Parc
20, BE-7000 Mons, and
| | - Zoltán G. Soos
- Department
of Chemistry, Princeton University, Princeton, New Jersey 08544, United States
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33
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Mityashin A, Roscioni OM, Muccioli L, Zannoni C, Geskin V, Cornil J, Janssen D, Steudel S, Genoe J, Heremans P. Multiscale modeling of the electrostatic impact of self-assembled monolayers used as gate dielectric treatment in organic thin-film transistors. ACS Appl Mater Interfaces 2014; 6:15372-8. [PMID: 25119143 DOI: 10.1021/am503873f] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
This study sheds light on the microscopic mechanisms by which self-assembled monolayers (SAMs) determine the onset voltage in organic thin-film transistors (OTFTs). Experiments and modeling are combined to investigate the self-assembly and electrostatic interaction processes in prototypical OTFT structures (SiO2/SAM/pentacene), where alkylated and fluoroalkylated silane SAMs are compared. The results highlight the coverage-dependent impact of the SAM on the density of semiconductor states and enable the rationalization and the control of the OTFT characteristics.
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34
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Olivier Y, Muccioli L, Zannoni C. Quinquephenyl: The Simplest Rigid-Rod-Like Nematic Liquid Crystal, or is it? An Atomistic Simulation. Chemphyschem 2014; 15:1345-55. [DOI: 10.1002/cphc.201301126] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2013] [Indexed: 11/10/2022]
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35
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Pizzirusso A, Di Pietro ME, De Luca G, Celebre G, Longeri M, Muccioli L, Zannoni C. Order and Conformation of Biphenyl in Cyanobiphenyl Liquid Crystals: A Combined Atomistic Molecular Dynamics and1H NMR Study. Chemphyschem 2014; 15:1356-67. [DOI: 10.1002/cphc.201400082] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Indexed: 11/07/2022]
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36
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Idé J, Méreau R, Ducasse L, Castet F, Bock H, Olivier Y, Cornil J, Beljonne D, D’Avino G, Roscioni OM, Muccioli L, Zannoni C. Charge Dissociation at Interfaces between Discotic Liquid Crystals: The Surprising Role of Column Mismatch. J Am Chem Soc 2014; 136:2911-20. [DOI: 10.1021/ja4114769] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Julien Idé
- Institut
des Sciences Moléculaires, UMR CNRS 5255, Université de Bordeaux, Cours de la Libération 351, FR-33405 Talence, France
- Dipartimento
di Chimica, Materiali e Ingegneria Chimica “G. Natta”, Politecnico di Milano, via Mancinelli 7, IT-20131 Milano, Italy
| | - Raphaël Méreau
- Institut
des Sciences Moléculaires, UMR CNRS 5255, Université de Bordeaux, Cours de la Libération 351, FR-33405 Talence, France
| | - Laurent Ducasse
- Institut
des Sciences Moléculaires, UMR CNRS 5255, Université de Bordeaux, Cours de la Libération 351, FR-33405 Talence, France
| | - Frédéric Castet
- Institut
des Sciences Moléculaires, UMR CNRS 5255, Université de Bordeaux, Cours de la Libération 351, FR-33405 Talence, France
| | - Harald Bock
- Centre
de Recherche Paul Pascal, UPR CNRS 8641, Université de Bordeaux, Avenue Schweitzer 115, FR-33600 Pessac, France
| | - Yoann Olivier
- Laboratory
for Chemistry of Novel Materials, University of Mons, Place du Parc
20, BE-7000 Mons, Belgium
| | - Jérôme Cornil
- Laboratory
for Chemistry of Novel Materials, University of Mons, Place du Parc
20, BE-7000 Mons, Belgium
| | - David Beljonne
- Laboratory
for Chemistry of Novel Materials, University of Mons, Place du Parc
20, BE-7000 Mons, Belgium
| | - Gabriele D’Avino
- Department
of Industrial Chemistry “Toso Montanari” and INSTM, University of Bologna, Viale del Risorgimento 4, IT-40136 Bologna, Italy
| | - Otello Maria Roscioni
- Department
of Industrial Chemistry “Toso Montanari” and INSTM, University of Bologna, Viale del Risorgimento 4, IT-40136 Bologna, Italy
| | - Luca Muccioli
- Department
of Industrial Chemistry “Toso Montanari” and INSTM, University of Bologna, Viale del Risorgimento 4, IT-40136 Bologna, Italy
| | - Claudio Zannoni
- Department
of Industrial Chemistry “Toso Montanari” and INSTM, University of Bologna, Viale del Risorgimento 4, IT-40136 Bologna, Italy
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37
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Catalano D, Forte C, Veracini CA, Zannoni C. The Orientational Ordering of Some Non-cylindrically Symmetric Solutes in Nematic Solvents. Isr J Chem 2013. [DOI: 10.1002/ijch.198300041] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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38
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Lemaur V, Muccioli L, Zannoni C, Beljonne D, Lazzaroni R, Cornil J, Olivier Y. On the Supramolecular Packing of High Electron Mobility Naphthalene Diimide Copolymers: The Perfect Registry of Asymmetric Branched Alkyl Side Chains. Macromolecules 2013. [DOI: 10.1021/ma401124r] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- Vincent Lemaur
- Laboratory
for Chemistry of Novel Materials, University of Mons-UMONS, Place
du Parc 20, B-7000 Mons, Belgium
| | - Luca Muccioli
- Dipartimento
di Chimica Industriale “Toso Montanari” and INSTM, Università di Bologna, Viale Risorgimento 4, IT-40136 Bologna, Italy
| | - Claudio Zannoni
- Dipartimento
di Chimica Industriale “Toso Montanari” and INSTM, Università di Bologna, Viale Risorgimento 4, IT-40136 Bologna, Italy
| | - David Beljonne
- Laboratory
for Chemistry of Novel Materials, University of Mons-UMONS, Place
du Parc 20, B-7000 Mons, Belgium
| | - Roberto Lazzaroni
- Laboratory
for Chemistry of Novel Materials, University of Mons-UMONS, Place
du Parc 20, B-7000 Mons, Belgium
| | - Jérôme Cornil
- Laboratory
for Chemistry of Novel Materials, University of Mons-UMONS, Place
du Parc 20, B-7000 Mons, Belgium
| | - Yoann Olivier
- Laboratory
for Chemistry of Novel Materials, University of Mons-UMONS, Place
du Parc 20, B-7000 Mons, Belgium
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39
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Roscioni OM, Muccioli L, Della Valle RG, Pizzirusso A, Ricci M, Zannoni C. Predicting the anchoring of liquid crystals at a solid surface: 5-cyanobiphenyl on cristobalite and glassy silica surfaces of increasing roughness. Langmuir 2013; 29:8950-8. [PMID: 23597166 DOI: 10.1021/la400857s] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
We employ atomistic molecular dynamics simulations to predict the alignment and anchoring strength of a typical nematic liquid crystal, 4-n-pentyl-4'-cyano biphenyl (5CB), on different forms of silica. In particular, we study a thin (~20 nm) film of 5CB supported on surfaces of crystalline (cristobalite) and amorphous silica of different roughness. We find that the orientational order at the surface and the anchoring strength depend on the morphology of the silica surface and its roughness. Cristobalite yields a uniform planar orientation and increases the order at the surface with respect to the bulk whereas amorphous glass has a disordering effect. Despite the low order at the amorphous surfaces, a planar orientation is established with a persistence length into the film higher than the one obtained for cristobalite.
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Affiliation(s)
- Otello Maria Roscioni
- Diartimento di Chimica Industriale Toso Montanari and INSTM, Università di Bologna, Bologna, Italy
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40
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Palermo MF, Pizzirusso A, Muccioli L, Zannoni C. An atomistic description of the nematic and smectic phases of 4-n-octyl-4′ cyanobiphenyl (8CB). J Chem Phys 2013; 138:204901. [DOI: 10.1063/1.4804270] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
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41
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Cornil J, Verlaak S, Martinelli N, Mityashin A, Olivier Y, Van Regemorter T, D’Avino G, Muccioli L, Zannoni C, Castet F, Beljonne D, Heremans P. Exploring the energy landscape of the charge transport levels in organic semiconductors at the molecular scale. Acc Chem Res 2013; 46:434-43. [PMID: 23140088 DOI: 10.1021/ar300198p] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The extraordinary semiconducting properties of conjugated organic materials continue to attract attention across disciplines including materials science, engineering, chemistry, and physics, particularly with application to organic electronics. Such materials are used as active components in light-emitting diodes, field-effect transistors, or photovoltaic cells, as a substitute for (mostly Si-based) inorganic semiconducting materials. Many strategies developed for inorganic semiconductor device building (doping, p-n junctions, etc.) have been attempted, often successfully, with organics, even though the key electronic and photophysical properties of organic thin films are fundamentally different from those of their bulk inorganic counterparts. In particular, organic materials consist of individual units (molecules or conjugated segments) that are coupled by weak intermolecular forces. The flexibility of organic synthesis has allowed the development of more efficient opto-electronic devices including impressive improvements in quantum yields for charge generation in organic solar cells and in light emission in electroluminescent displays. Nonetheless, a number of fundamental questions regarding the working principles of these devices remain that preclude their full optimization. For example, the role of intermolecular interactions in driving the geometric and electronic structures of solid-state conjugated materials, though ubiquitous in organic electronic devices, has long been overlooked, especially when it comes to these interfaces with other (in)organic materials or metals. Because they are soft and in most cases disordered, conjugated organic materials support localized electrons or holes associated with local geometric distortions, also known as polarons, as primary charge carriers. The spatial localization of excess charges in organics together with low dielectric constant (ε) entails very large electrostatic effects. It is therefore not obvious how these strongly interacting electron-hole pairs can potentially escape from their Coulomb well, a process that is at the heart of photoconversion or molecular doping. Yet they do, with near-quantitative yield in some cases. Limited screening by the low dielectric medium in organic materials leads to subtle static and dynamic electronic polarization effects that strongly impact the energy landscape for charges, which offers a rationale for this apparent inconsistency. In this Account, we use different theoretical approaches to predict the energy landscape of charge carriers at the molecular level and review a few case studies highlighting the role of electrostatic interactions in conjugated organic molecules. We describe the pros and cons of different theoretical approaches that provide access to the energy landscape defining the motion of charge carriers. We illustrate the applications of these approaches through selected examples involving OFETs, OLEDs, and solar cells. The three selected examples collectively show that energetic disorder governs device performances and highlights the relevance of theoretical tools to probe energy landscapes in molecular assemblies.
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Affiliation(s)
- J. Cornil
- Laboratory for Chemistry of Novel Materials, University of Mons, Place du Parc 20, B-7000 Mons, Belgium
| | - S. Verlaak
- imec, Kapeldreef 75, B-3001, Leuven, Belgium
| | - N. Martinelli
- Laboratory for Chemistry of Novel Materials, University of Mons, Place du Parc 20, B-7000 Mons, Belgium
| | - A. Mityashin
- imec, Kapeldreef 75, B-3001, Leuven, Belgium
- ESAT, Katholieke Universiteit Leuven, Kasteelpark Arenberg 10, B-3001 Leuven, Belgium
| | - Y. Olivier
- Laboratory for Chemistry of Novel Materials, University of Mons, Place du Parc 20, B-7000 Mons, Belgium
| | - T. Van Regemorter
- Laboratory for Chemistry of Novel Materials, University of Mons, Place du Parc 20, B-7000 Mons, Belgium
| | - G. D’Avino
- Dipartimento di Chimica Fisica e Inorganica and INSTM, Università di Bologna, IT-40136 Bologna, Italy
| | - L. Muccioli
- Dipartimento di Chimica Fisica e Inorganica and INSTM, Università di Bologna, IT-40136 Bologna, Italy
| | - C. Zannoni
- Dipartimento di Chimica Fisica e Inorganica and INSTM, Università di Bologna, IT-40136 Bologna, Italy
| | - F. Castet
- Institut des Sciences Moléculaires, UMR CNRS 5255, Université de Bordeaux, Cours de la Libération 351, FR-33405 Talence, France
| | - D. Beljonne
- Laboratory for Chemistry of Novel Materials, University of Mons, Place du Parc 20, B-7000 Mons, Belgium
| | - P. Heremans
- imec, Kapeldreef 75, B-3001, Leuven, Belgium
- ESAT, Katholieke Universiteit Leuven, Kasteelpark Arenberg 10, B-3001 Leuven, Belgium
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42
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Querciagrossa L, Ricci M, Berardi R, Zannoni C. Mesogen polarity effects on biaxial nematics. Centrally located dipoles. Phys Chem Chem Phys 2013; 15:19065-72. [DOI: 10.1039/c3cp52970c] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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43
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Muccioli L, D’Avino G, Berardi R, Orlandi S, Pizzirusso A, Ricci M, Roscioni OM, Zannoni C. Supramolecular Organization of Functional Organic Materials in the Bulk and at Organic/Organic Interfaces: A Modeling and Computer Simulation Approach. Top Curr Chem (Cham) 2013; 352:39-101. [DOI: 10.1007/128_2013_470] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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44
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Weber ACJ, Pizzirusso A, Muccioli L, Zannoni C, Meerts WL, de Lange CA, Burnell EE. Efficient analysis of highly complex nuclear magnetic resonance spectra of flexible solutes in ordered liquids by using molecular dynamics. J Chem Phys 2012; 136:174506. [DOI: 10.1063/1.4705271] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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45
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Pizzirusso A, Di Cicco MB, Tiberio G, Muccioli L, Berardi R, Zannoni C. Alignment of Small Organic Solutes in a Nematic Solvent: The Effect of Electrostatic Interactions. J Phys Chem B 2012; 116:3760-71. [DOI: 10.1021/jp3003799] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- A. Pizzirusso
- Dipartimento di Chimica Fisica e Inorganica, and INSTM, Viale Risorgimento 4, 40136 Bologna, Italy
| | - M. B. Di Cicco
- Dipartimento di Chimica Fisica e Inorganica, and INSTM, Viale Risorgimento 4, 40136 Bologna, Italy
| | - G. Tiberio
- Dipartimento di Chimica Fisica e Inorganica, and INSTM, Viale Risorgimento 4, 40136 Bologna, Italy
| | - L. Muccioli
- Dipartimento di Chimica Fisica e Inorganica, and INSTM, Viale Risorgimento 4, 40136 Bologna, Italy
| | - R. Berardi
- Dipartimento di Chimica Fisica e Inorganica, and INSTM, Viale Risorgimento 4, 40136 Bologna, Italy
| | - C. Zannoni
- Dipartimento di Chimica Fisica e Inorganica, and INSTM, Viale Risorgimento 4, 40136 Bologna, Italy
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46
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Pizzirusso A, Berardi R, Muccioli L, Ricci M, Zannoni C. Predicting surface anchoring: molecular organization across a thin film of 5CB liquid crystal on silicon. Chem Sci 2012. [DOI: 10.1039/c1sc00696g] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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47
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Lamarra M, Muccioli L, Orlandi S, Zannoni C. Temperature dependence of charge mobility in model discotic liquid crystals. Phys Chem Chem Phys 2012; 14:5368-75. [DOI: 10.1039/c2cp23178f] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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48
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Chiccoli C, Pasini P, Teixeira de Souza R, Evangelista LR, Zannoni C. Computer simulations of the ordering in a hybrid cylindrical film of nematic liquid crystals. Phys Rev E 2011; 84:041705. [PMID: 22181155 DOI: 10.1103/physreve.84.041705] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2011] [Indexed: 11/07/2022]
Abstract
We present an investigation of the ordering in a nematic liquid-crystal film confined between two cylindrical surfaces with antagonistic (radial and planar) anchoring alignments. A Monte Carlo study of a Lebwohl-Lasher model with suitable boundary conditions has been performed to calculate the ordering and the molecular organization for different film thicknesses. The simulation results are compared with some theoretical predictions obtained with the elastic continuum approach. The agreement between theory and simulation is improved as the thickness decreases.
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Affiliation(s)
- C Chiccoli
- Istituto Nazionale di Fisica Nucleare, Sezione di Bologna, Via Irnerio 46, I-40126 Bologna, Italy
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49
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Muccioli L, D'Avino G, Zannoni C. Simulation of vapor-phase deposition and growth of a pentacene thin film on C60 (001). Adv Mater 2011; 23:4532-4536. [PMID: 21901761 DOI: 10.1002/adma.201101652] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Revised: 07/06/2011] [Indexed: 05/31/2023]
Affiliation(s)
- Luca Muccioli
- Dipartimento di Chimica Fisica e Inorganica and INSTM, University of Bologna, viale Risorgimento 4, IT-40136 Bologna, Italy.
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50
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Berardi R, Lintuvuori JS, Wilson MR, Zannoni C. Phase diagram of the uniaxial and biaxial soft–core Gay–Berne model. J Chem Phys 2011; 135:134119. [DOI: 10.1063/1.3646310] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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