scholarly journals Geometry induced sequence of nanoscale Frank–Kasper and quasicrystal mesophases in giant surfactants

2016 ◽  
Vol 113 (50) ◽  
pp. 14195-14200 ◽  
Author(s):  
Kan Yue ◽  
Mingjun Huang ◽  
Ryan L. Marson ◽  
Jinlin He ◽  
Jiahao Huang ◽  
...  
Keyword(s):  
Self Assembly ◽  
Brownian Dynamics ◽  
Molecular Model ◽  
Critical Role ◽  
Sphere Packing ◽  
Molecular Geometry ◽  
Soft Materials ◽  
Real Space ◽  
Molecular Architecture ◽  
Self Assembled

Frank–Kasper (F-K) and quasicrystal phases were originally identified in metal alloys and only sporadically reported in soft materials. These unconventional sphere-packing schemes open up possibilities to design materials with different properties. The challenge in soft materials is how to correlate complex phases built from spheres with the tunable parameters of chemical composition and molecular architecture. Here, we report a complete sequence of various highly ordered mesophases by the self-assembly of specifically designed and synthesized giant surfactants, which are conjugates of hydrophilic polyhedral oligomeric silsesquioxane cages tethered with hydrophobic polystyrene tails. We show that the occurrence of these mesophases results from nanophase separation between the heads and tails and thus is critically dependent on molecular geometry. Variations in molecular geometry achieved by changing the number of tails from one to four not only shift compositional phase boundaries but also stabilize F-K and quasicrystal phases in regions where simple phases of spheroidal micelles are typically observed. These complex self-assembled nanostructures have been identified by combining X-ray scattering techniques and real-space electron microscopy images. Brownian dynamics simulations based on a simplified molecular model confirm the architecture-induced sequence of phases. Our results demonstrate the critical role of molecular architecture in dictating the formation of supramolecular crystals with “soft” spheroidal motifs and provide guidelines to the design of unconventional self-assembled nanostructures.

Nanoscale metallogel via self-assembly of self-assembled trinuclear coordination rings: multi-stimuli-responsive soft materials

2015 ◽  
Vol 44 (34) ◽  
pp. 15181-15188 ◽  
Author(s):  
Sudhakar Ganta ◽  
Dillip Kumar Chand
Keyword(s):  
Self Assembly ◽  
Soft Materials ◽  
The Self ◽  
Stimuli Responsive ◽  
Self Assembled

A multi-stimuli-responsive metallogel is obtained by the self-assembly of an already self-assembled trinuclear palladium(ii) based coordination ring of the rare M3L6 composition.

scholarly journals Soft self-assembly of Weyl materials for light and sound

2018 ◽  
Vol 115 (16) ◽  
pp. E3655-E3664 ◽  
Author(s):  
Michel Fruchart ◽  
Seung-Yeol Jeon ◽  
Kahyun Hur ◽  
Vadim Cheianov ◽  
Ulrich Wiesner ◽  
...  
Keyword(s):  
Self Assembly ◽  
Surface States ◽  
Material Design ◽  
Soft Materials ◽  
General Symmetry ◽  
Mesostructured Materials ◽  
Reversal Invariance ◽  
Symmetry Constraints ◽  
Topological Surface ◽  
Self Assembled

Soft materials can self-assemble into highly structured phases that replicate at the mesoscopic scale the symmetry of atomic crystals. As such, they offer an unparalleled platform to design mesostructured materials for light and sound. Here, we present a bottom-up approach based on self-assembly to engineer 3D photonic and phononic crystals with topologically protected Weyl points. In addition to angular and frequency selectivity of their bulk optical response, Weyl materials are endowed with topological surface states, which allow for the existence of one-way channels, even in the presence of time-reversal invariance. Using a combination of group-theoretical methods and numerical simulations, we identify the general symmetry constraints that a self-assembled structure has to satisfy to host Weyl points and describe how to achieve such constraints using a symmetry-driven pipeline for self-assembled material design and discovery. We illustrate our general approach using block copolymer self-assembly as a model system.

scholarly journals Low-symmetry sphere packings of simple surfactant micelles induced by ionic sphericity

2017 ◽  
Vol 114 (16) ◽  
pp. 4072-4077 ◽  
Author(s):  
Sung A Kim ◽  
Kyeong-Jun Jeong ◽  
Arun Yethiraj ◽  
Mahesh K. Mahanthappa
Keyword(s):  
Self Assembly ◽  
Liquid Crystalline ◽  
Sphere Packing ◽  
Soft Materials ◽  
Close Packing ◽  
High Symmetry ◽  
Length Scales ◽  
Σ Phase ◽  
Multiple Length Scales ◽  
Low Symmetry

Supramolecular self-assembly enables access to designer soft materials that typically exhibit high-symmetry packing arrangements, which optimize the interactions between their mesoscopic constituents over multiple length scales. We report the discovery of an ionic small molecule surfactant that undergoes water-induced self-assembly into spherical micelles, which pack into a previously unknown, low-symmetry lyotropic liquid crystalline Frank–Kasper σ phase. Small-angle X-ray scattering studies reveal that this complex phase is characterized by a gigantic tetragonal unit cell, in which 30 sub-2-nm quasispherical micelles of five discrete sizes are arranged into a tetrahedral close packing, with exceptional translational order over length scales exceeding 100 nm. Varying the relative concentrations of water and surfactant in these lyotropic phases also triggers formation of the related Frank–Kasper A15 sphere packing as well as a common body-centered cubic structure. Molecular dynamics simulations reveal that the symmetry breaking that drives the formation of the σ and A15 phases arises from minimization of local deviations in surfactant headgroup and counterion solvation to maintain a nearly spherical counterion atmosphere around each micelle, while maximizing counterion-mediated electrostatic cohesion among the ensemble of charged particles.

SELF-ASSEMBLY ARCHITECTURES OF NEW DNA-BASED STRUCTURES IN AIR AND IN LIQUIDS ANALYZED BY ATOMIC FORCE MICROSCOPY

2012 ◽  
Vol 11 (04) ◽  
pp. 1240017 ◽  
Author(s):  
M. IAZYKOV ◽  
D. SICARD ◽  
Y. CHEVOLOT ◽  
E. SOUTEYRAND ◽  
M. PHANER-GOUTORBE ◽  
...  
Keyword(s):  
Atomic Force Microscopy ◽  
Surface Treatment ◽  
Self Assembly ◽  
Molecular Model ◽  
Mica Surface ◽  
Buffer Solution ◽  
Force Microscopy ◽  
Atomic Force ◽  
Self Assembled ◽  
Tris Buffer Solution

The architecture of self assembled X shaped DNA structure was studied by AFM on mica. The dimensions and extent of self assembled structures were influenced by mica surface treatment and depended on whether observations were performed in air or in Tris buffer solution. A molecular model is proposed.

scholarly journals A molecular model of the surface-assisted protein aggregation process

2018 ◽  
Author(s):  
Y.G. Pan ◽  
S. Banerjee ◽  
K. Zagorski ◽  
L.S. Shlyakhtenko ◽  
A.B. Kolomeisky ◽  
...  
Keyword(s):  
Self Assembly ◽  
Molecular Mechanisms ◽  
Molecular Model ◽  
Critical Role ◽  
Experimental Studies ◽  
Cytosine Deaminase ◽  
Aggregation Process ◽  
Amyloidogenic Proteins ◽  
Low Concentrations ◽  
Kinetics Of

AbstractThe importance of cell surfaces in the self-assembly of proteins is widely accepted. One biologically significant event is the assembly of amyloidogenic proteins into aggregates, which leads to neurodegenerative disorders like Alzheimer’s and Parkinson’s. The interaction of amyloidogenic proteins with cellular membranes appears to dramatically facilitate the aggregation process. Recent findings indicate that, in the presence of surfaces, aggregation occurs at physiologically low concentrations, suggesting interaction with surfaces plays a critical role in the disease-prone aggregation process. However, the molecular mechanisms behind on-surface aggregation remain unclear. Here we provide a theoretical model that offers a molecular explanation. According to this model, monomers transiently immobilized to surfaces increase the local monomer protein concentration and thus work as nuclei to dramatically accelerate the entire aggregation process. This theory was verified by experimental studies, using mica surfaces, to examine the aggregation kinetics of amyloidogenic-synuclein protein (α-Syn) and non-amyloidogenic cytosine deaminase APOBEC3G (A3G).

Exploration of cell wall architecture with the rapid-freeze deep-etch technique

1993 ◽  
Vol 51 ◽  
pp. 128-129
Author(s):  
Béatrice Satiat-Jeunemaitre ◽  
Chris Hawes
Keyword(s):  
Plant Cell ◽  
Cell Walls ◽  
Cell Biology ◽  
Molecular Model ◽  
Three Dimensional ◽  
Secretory Activity ◽  
Wall Structure ◽  
Specimen Preparation ◽  
Molecular Architecture ◽  
Plant Cell Walls

The comprehension of the molecular architecture of plant cell walls is one of the best examples in cell biology which illustrates how developments in microscopy have extended the frontiers of a topic. Indeed from the first electron microscope observation of cell walls it has become apparent that our understanding of wall structure has advanced hand in hand with improvements in the technology of specimen preparation for electron microscopy. Cell walls are sub-cellular compartments outside the peripheral plasma membrane, the construction of which depends on a complex cellular biosynthetic and secretory activity (1). They are composed of interwoven polymers, synthesised independently, which together perform a number of varied functions. Biochemical studies have provided us with much data on the varied molecular composition of plant cell walls. However, the detailed intermolecular relationships and the three dimensional arrangement of the polymers in situ remains a mystery. The difficulty in establishing a general molecular model for plant cell walls is also complicated by the vast diversity in wall composition among plant species.

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 of a Chiral Cubic Three-Connected Net from the High Symmetry Molecules C60 and SnI4

2020 ◽  
Author(s):  
Daniel B. Straus ◽  
Robert J. Cava
Keyword(s):  
Organic Synthesis ◽  
Self Assembly ◽  
Van Der Waals ◽  
Van Der Waals Forces ◽  
High Symmetry ◽  
Molecular Chirality ◽  
Chiral Materials ◽  
Self Assembled ◽  
Chiral Centers

The design of new chiral materials usually requires stereoselective organic synthesis to create molecules with chiral centers. Less commonly, achiral molecules can self-assemble into chiral materials, despite the absence of intrinsic molecular chirality. Here, we demonstrate the assembly of high-symmetry molecules into a chiral van der Waals structure by synthesizing crystals of C<sub>60</sub>(SnI<sub>4</sub>)<sub>2</sub> from icosahedral buckminsterfullerene (C<sub>60</sub>) and tetrahedral SnI4 molecules through spontaneous self-assembly. The SnI<sub>4</sub> tetrahedra template the Sn atoms into a chiral cubic three-connected net of the SrSi<sub>2</sub> type that is held together by van der Waals forces. Our results represent the remarkable emergence of a self-assembled chiral material from two of the most highly symmetric molecules, demonstrating that almost any molecular, nanocrystalline, or engineered precursor can be considered when designing chiral assemblies.

scholarly journals Nano- and Micropatterning on Optical Fibers by Bottom-Up Approach: The Importance of Being Ordered

2021 ◽  
Vol 11 (7) ◽  
pp. 3254
Author(s):  
Marco Pisco ◽  
Francesco Galeotti
Keyword(s):  
Optical Fiber ◽  
Optical Fibers ◽  
Self Assembly ◽  
Ordered Structures ◽  
Bottom Up ◽  
Photonic Structures ◽  
Fiber Technology ◽  
Optical Fiber Probes ◽  
Fiber Probes ◽  
Self Assembled

The realization of advanced optical fiber probes demands the integration of materials and structures on optical fibers with micro- and nanoscale definition. Although researchers often choose complex nanofabrication tools to implement their designs, the migration from proof-of-principle devices to mass production lab-on-fiber devices requires the development of sustainable and reliable technology for cost-effective production. To make it possible, continuous efforts are devoted to applying bottom-up nanofabrication based on self-assembly to decorate the optical fiber with highly ordered photonic structures. The main challenges still pertain to “order” attainment and the limited number of implementable geometries. In this review, we try to shed light on the importance of self-assembled ordered patterns for lab-on-fiber technology. After a brief presentation of the light manipulation possibilities concerned with ordered structures, and of the new prospects offered by aperiodically ordered structures, we briefly recall how the bottom-up approach can be applied to create ordered patterns on the optical fiber. Then, we present un-attempted methodologies, which can enlarge the set of achievable structures, and can potentially improve the yielding rate in finely ordered self-assembled optical fiber probes by eliminating undesired defects and increasing the order by post-processing treatments. Finally, we discuss the available tools to quantify the degree of order in the obtained photonic structures, by suggesting the use of key performance figures of merit in order to systematically evaluate to what extent the pattern is really “ordered”. We hope such a collection of articles and discussion herein could inspire new directions and hint at best practices to fully exploit the benefits inherent to self-organization phenomena leading to ordered systems.

scholarly journals Self-assembled interpenetrating networks by orthogonal self assembly of surfactants and hydrogelators

2009 ◽  
Vol 143 ◽  
pp. 345 ◽  
Author(s):  
Aurelie M. Brizard ◽  
Marc C. A. Stuart ◽  
Jan H. van Esch
Keyword(s):  
Self Assembly ◽  
Interpenetrating Networks ◽  
Self Assembled
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