scholarly journals Complex tiling patterns in liquid crystals

2011 ◽  
Vol 2 (5) ◽  
pp. 669-680 ◽  
Author(s):  
C. Tschierske ◽  
C. Nürnberger ◽  
H. Ebert ◽  
B. Glettner ◽  
M. Prehm ◽  
...  
Keyword(s):  
Self Assembly ◽  
Liquid Crystalline ◽  
Periodic Structures ◽  
Three Dimensional ◽  
Lateral Position ◽  
Molecular Structures ◽  
Rod Bundles ◽  
Geometric Frustration ◽  
Periodic Tiling ◽  
Tiling Patterns

In this account recent progress in enhancing the complexity of liquid crystal self-assembly is highlighted. The discussed superstructures are formed mainly by polyphilic T-shaped and X-shaped molecules composed of a rod-like core, tethered with glycerol units at both ends and flexible non-polar chain(s) in lateral position, but also related inverted molecular structures are considered. A series of honeycomb phases composed of polygonal cylinders ranging from triangular to hexagonal, followed by giant cylinder honeycombs is observed for ternary T-shaped polyphiles on increasing the size of the lateral chain(s). Increasing the chain size further leads to new modes of lamellar organization followed by three-dimensional and two-dimensional structures incorporating branched and non-branched axial rod-bundles. Grafting incompatible chains to opposite sides of the rod-like core leads to quaternary X-shaped polyphiles. These form liquid crystalline honeycombs where different cells are filled with different material. Projected on an Euclidian plane, all honeycomb phases can be described either by uniformly coloured Archimedean and Laves tiling patterns (T-shaped polyphiles) or as multi-colour tiling patterns (X-shaped polyphiles). It is shown that geometric frustration, combined with the tendency to segregate incompatible chains into different compartments and the need to find a periodic tiling pattern, leads to a significant increase in the complexity of soft self-assembly. Mixing of different chains greatly enhances the number of possible ‘colours’ and in this way, periodic structures comprising up to seven distinct compartments can be generated. Relations to biological self-assembly are discussed shortly.

Scanning Tunneling Microscopy Study of α,ω-Dihexylsexithiophene Adlayers on Au(111): A Chiral Separation Induced by a Surface

2012 ◽  
Vol 18 (4) ◽  
pp. 885-891 ◽  
Author(s):  
Yonghai Song ◽  
Yu Wang ◽  
Lingli Wan ◽  
Shuhong Ye ◽  
Haoqing Hou ◽  
...  
Keyword(s):  
Scanning Tunneling Microscopy ◽  
Self Assembly ◽  
Room Temperature ◽  
Three Dimensional ◽  
Microscopy Study ◽  
Molecular Structures ◽  
Scanning Tunneling ◽  
Tunneling Microscopy ◽  
Left Handed ◽  
Bulk Structure

AbstractThe self-assembly of α,ω-dihexylsexithiophene molecules on an Au(111) surface was examined by using scanning tunneling microscopy at room temperature, revealing the internal molecular structures of the sexithiophene backbones and the hexyl side chains. The α,ω-dihexylsexithiophene formed a large and well-ordered monolayer in which the molecule lay flatly on the Au(111) surface and was separated into two chiral domains. A detailed observation reveals that the admolecules were packed in one lamellae with their molecular axis aligned along the main axis of the Au(111) substrate with their hexyl chains deviated from ⟨110⟩ direction of the Au(111) substrate by 12 ± 0.5°. In contrast to the behavior in the three-dimensional bulk structure, flat-lying adsorption introduced molecular chirality: right- and left-handed molecules separate into domains of two different orientations, which are mirror symmetric with respect to the ⟨121⟩ direction of the Au(111) substrate. Details of the adlayer structure and the chiral self-assembly were discussed here.

Preparation of microparts for fabricating three-dimensional periodic structures by self-assembly

2016 ◽  
Vol 2016 (0) ◽  
pp. J2240201
Author(s):  
Yuki Iijima ◽  
Mizue Mizoshiri ◽  
Junpei Sakurai ◽  
Seiichi Hata
Keyword(s):  
Self Assembly ◽  
Periodic Structures ◽  
Three Dimensional

Self-Assembly Of 1D- And 3D-Networks Through Non-Coordination Intermolecular Forces: Synthesis And Crystal Structures Of Copper(I) Complexes Based On Pyridazine-Type Ligands

2007 ◽  
Vol 62 (6) ◽  
pp. 799-806 ◽  
Author(s):  
Laurent Plasseraud ◽  
Andreas Scheurer ◽  
Frank Hampel
Keyword(s):  
Solid State ◽  
Self Assembly ◽  
Three Dimensional ◽  
Intermolecular Forces ◽  
Molecular Structures ◽  
Dinuclear Complexes ◽  
Stacking Interactions ◽  
The Novel ◽  
X Ray ◽  
3D Networks

Reaction of [Cu2(H3CCN)2(μ-pydz)3][PF6]2 (1) with an excess of pyridazine or phthalazine yielded the novel dinuclear complexes [Cu2(μ-pydz)3(pydz)2][PF6]2 (2) and [Cu2 (μ- pydz)(μ-phtz)2(phtz)2][PF6]2 (5), respectively. Depolymerisation of the coordination polymer 1∞ {[Cu(μ-pydz)2][PF6]} (3) in dichloromethane by addition of an excess of benzo[c]cinnoline afforded the dinuclear copper(I) salt [Cu2(μ-pydz)2(pydz)2(benzo[c]cinnoline)2][PF6]2 (4). Furthermore, a new route for the preparation of bis(benzonitrile)tris(μ-phthalazine)dicopper(I) bis(trifluoromethanesulfonate), [Cu2(C6H5CN)2(μ-phtz)3][CF3SO3]2 (7), was established from {[Cu(CF3SO3)]2 ・C6H5Me}, phthalazine and benzonitrile via the very air-sensitive intermediate [Cu2(CF3SO3)2(μ-phtz)3] (6). Copper(I) compounds 2, 4, and 7 were completely characterised and the molecular structures confirmed in the solid state by single-crystal X-ray structure determination. The analysis of the packing of the molecules in crystals of 4 and 7 revealed a self-assembly of oneand three-dimensional frameworks, respectively, resulting from intermolecular π-π stacking interactions between pyridazine-type ligands

scholarly journals Cubosomes as Potential Nanocarrier for Drug Delivery: A Comprehensive Review

2021 ◽  
pp. 118-135
Author(s):  
Simran Deep Kaur ◽  
Gurdeep Singh ◽  
Gurpreet Singh ◽  
Keshav Singhal ◽  
Shubham Kant ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Self Assembly ◽  
Liquid Crystalline ◽  
Three Dimensional ◽  
Lipid Nanoparticles ◽  
Site Specific ◽  
Cubic Symmetry ◽  
Amphiphilic Drugs ◽  
Carrier Systems ◽  
Soft Nanoparticles

Lyotropic liquid crystalline cores are characterized as soft nanoparticles and referred as cubosomes.  They are prepared to activate the natural self-assembly capability of lipids (e.g., monoolein or phytantriol) in water. Cubosomes are crystalline isotropic lipidic nanoparticles stabilized by Poloxamers such as F127, F108. It is made up of a network of two separate aqueous channels formed by a three-dimensional, non-intersecting lipid bilayer imposed over an indefinite periodic minimum surface of cubic symmetry. Cubosomes constitute unique features such as their special cubic structure which permits to incorporate highly lipophilic, hydrophilic, and amphiphilic drugs. Also, the lipids excipients used in the preparation of cubosomes such as monoolein, phytantriol are biodegradable and biocompatible so these cubic nanoparticles are referred as safe carrier for drug delivery. Cubic lipid nanoparticles have a highly stable cubic shape that allows for a slower rate of dissociation, improved drug retention, and site-specific drug delivery. The architecture of cubic particles provides suitability in the drug delivery as compared to other lipids-based drug delivery systems such as solid lipid nanoparticles (SLN), liposomes due to their drug expulsion to the surface of nanoparticles. Cubosomes with these loaded features/architectural composition led to an array of desired performance. Solvent evaporation, ultrasonication, hydrotrope, spray drying, melt dispersion emulsifying methods are used to prepare these carrier systems.

scholarly journals Soft Rectangular Sub-5 nm Tiling Patterns by Liquid Crystalline Self-Assembly of T-Shaped Bolapolyphiles

2018 ◽  
Vol 28 (46) ◽  
pp. 1804162 ◽  
Author(s):  
Anne Lehmann ◽  
Alexander Scholte ◽  
Marko Prehm ◽  
Feng Liu ◽  
Xiangbing Zeng ◽  
...  
Keyword(s):  
Self Assembly ◽  
Liquid Crystalline ◽  
Tiling Patterns

Structure-Property Relationships of Quinoxaline Based Liquid Crystals

Soft Matter ◽  
2021 ◽  
Author(s):  
Vinod Kumar Vishwakarma ◽  
Achalkumar Ammathnadu Sudhakar
Keyword(s):  
Liquid Crystals ◽  
Self Assembly ◽  
Liquid Crystalline ◽  
Molecular Engineering ◽  
Molecular Structures ◽  
Structure Property ◽  
Structure Property Relationships ◽  
Quinoxaline Derivatives

Quinoxaline derivatives with different molecular structures stabilizing liquid crystalline self-assembly are discussed in this review. This class of molecules can be systematically modified with careful molecular engineering to achieve different...

In vitro and in vivo polysaccharides assembly: ultrastructural and cytochemical study of growing plant cell wall components.

1978 ◽  
Vol 36 (2) ◽  
pp. 434-435
Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland
Keyword(s):  
Cell Wall ◽  
Self Assembly ◽  
Plant Cell Wall ◽  
Higher Plants ◽  
Three Dimensional ◽  
Cytochemical Study ◽  
Wall Components

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.

Nanoscale Self-Assembly Using Ion and Electron Beam Techniques: A Rapid Review

MRS Advances ◽  
2020 ◽  
Vol 5 (64) ◽  
pp. 3507-3520
Author(s):  
Chunhui Dai ◽  
Kriti Agarwal ◽  
Jeong-Hyun Cho
Keyword(s):  
Electron Beam ◽  
Self Assembly ◽  
Ion Beam ◽  
Three Dimensional ◽  
The Self ◽  
Stress Generation ◽  
Rapid Review ◽  
High Yield ◽  
3D Nanostructures ◽  
Self Assembled

AbstractNanoscale self-assembly, as a technique to transform two-dimensional (2D) planar patterns into three-dimensional (3D) nanoscale architectures, has achieved tremendous success in the past decade. However, an assembly process at nanoscale is easily affected by small unavoidable variations in sample conditions and reaction environment, resulting in a low yield. Recently, in-situ monitored self-assembly based on ion and electron irradiation has stood out as a promising candidate to overcome this limitation. The usage of ion and electron beam allows stress generation and real-time observation simultaneously, which significantly enhances the controllability of self-assembly. This enables the realization of various complex 3D nanostructures with a high yield. The additional dimension of the self-assembled 3D nanostructures opens the possibility to explore novel properties that cannot be demonstrated in 2D planar patterns. Here, we present a rapid review on the recent achievements and challenges in nanoscale self-assembly using electron and ion beam techniques, followed by a discussion of the novel optical properties achieved in the self-assembled 3D nanostructures.

Self-Assembly Optical Components

2003 ◽  
Vol 771 ◽  
Author(s):  
Pavel I. Lazarev ◽  
Michael V. Paukshto ◽  
Elena N. Sidorenko
Keyword(s):  
Optical Properties ◽  
Self Assembly ◽  
Crystalline State ◽  
Liquid Crystalline ◽  
Film Deposition ◽  
X Ray Diffraction ◽  
Optical Components ◽  
Crystal Film ◽  
Solid Film ◽  
Thin Crystal

AbstractWe report a new method of Thin Crystal Film deposition. In the present paper we describe the method of crystallization, structure, and optical properties of Bisbenzimidazo[2,1-a:1',2',b']anthra[2,1,9-def:6,5,10-d'e'f']-diisoquinoline-6,9-dion (mixture with cis-isomer) (abbreviated DBI PTCA) sulfonation product. The Thin Crystal Film has a thickness of 200-1000 nm, with anisotropic optical properties such as refraction and absorption indices. X-ray diffraction data evidences a lyotropic liquid crystalline state in liquid phase and crystalline state in solid film. Anisotropic optical properties of the film make it useful in optical devices, e.g. liquid crystal displays.

Factors Affecting Molecular Self-Assembly and Its Mechanism

2012 ◽  
Vol 9 (1) ◽  
pp. 43 ◽  
Author(s):  
Hueyling Tan
Keyword(s):  
Self Assembly ◽  
Building Blocks ◽  
Molecular Engineering ◽  
Molecular Structures ◽  
Polymer Science ◽  
New Approach ◽  
Factors Affecting ◽  
Dna Structures ◽  
Self Assembling ◽  
Wide Range

Molecular self-assembly is ubiquitous in nature and has emerged as a new approach to produce new materials in chemistry, engineering, nanotechnology, polymer science and materials. Molecular self-assembly has been attracting increasing interest from the scientific community in recent years due to its importance in understanding biology and a variety of diseases at the molecular level. In the last few years, considerable advances have been made in the use ofpeptides as building blocks to produce biological materials for wide range of applications, including fabricating novel supra-molecular structures and scaffolding for tissue repair. The study ofbiological self-assembly systems represents a significant advancement in molecular engineering and is a rapidly growing scientific and engineering field that crosses the boundaries ofexisting disciplines. Many self-assembling systems are rangefrom bi- andtri-block copolymers to DNA structures as well as simple and complex proteins andpeptides. The ultimate goal is to harness molecular self-assembly such that design andcontrol ofbottom-up processes is achieved thereby enabling exploitation of structures developed at the meso- and macro-scopic scale for the purposes oflife and non-life science applications. Such aspirations can be achievedthrough understanding thefundamental principles behind the selforganisation and self-synthesis processes exhibited by biological systems.

Sign in / Sign up

Export Citation Format

Share Document