scholarly journals Globular pattern formation of hierarchical ceria nanoarchitecture

2021 ◽  
Author(s):  
Noboru Aoyagi ◽  
Ryuhei Motokawa ◽  
Masahiko Okumura ◽  
Takumi Saito ◽  
Shotaro Nishitsuji ◽  
...  
Keyword(s):  
Self Assembly ◽  
Dissipative Structures ◽  
Ordered Structures ◽  
Seed Formation ◽  
Acidic Aqueous Solution ◽  
Multiphase Mixture ◽  
Stability And Instability ◽  
Primary Core ◽  
Far From Equilibrium ◽  
Crystal Seed

Abstract Dissipative structures often appear as an unstable counterpart of ordered structures owing to fluctuations that do not form a homogeneous phase. Even a multiphase mixture may simultaneously undergo one chemical reaction near equilibrium and another one that is far from equilibrium. Here, we observed in real time crystal seed formation and simultaneous nanocrystal aggregation proceeding from CeIV complexes to CeO2 nanoparticles in an acidic aqueous solution, and investigated the resultant hierarchical nanoarchitecture. The formed particles exhibited two very different size ranges. The hierarchically assembled structures in solutions were CeO2 colloids, viz. primary core clusters (1–3 nm) of crystalline ceria and secondary clusters (20–30 nm) assembled through surface ions. Such self-assembly is widespread in multi-component complex fluids, paradoxically moderating hierarchical reactions. Stability and instability are not only critical but also complementary for co-optimisation around the nearby free energy landscape prior to bifurcation.

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 Precise Synthesis and Thin Film Self-Assembly of PLLA-b-PS Bottlebrush Block Copolymers

Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1412
Author(s):  
Eunkyung Ji ◽  
Cian Cummins ◽  
Guillaume Fleury
Keyword(s):  
Thin Film ◽  
Block Copolymers ◽  
Self Assembly ◽  
Ring Opening ◽  
Periodic Structures ◽  
One Pot ◽  
Ordered Structures ◽  
Carbonyl Chloride ◽  
Thin Film Patterning ◽  
Nanoporous Templates

The ability of bottlebrush block copolymers (BBCPs) to self-assemble into ordered large periodic structures could greatly expand the scope of photonic and membrane technologies. In this paper, we describe a two-step synthesis of poly(l-lactide)-b-polystyrene (PLLA-b-PS) BBCPs and their rapid thin-film self-assembly. PLLA chains were grown from exo-5-norbornene-2-methanol via ring-opening polymerization (ROP) of l-lactide to produce norbornene-terminated PLLA. Norbonene-terminated PS was prepared using anionic polymerization followed by a termination reaction with exo-5-norbornene-2-carbonyl chloride. PLLA-b-PS BBCPs were prepared from these two norbornenyl macromonomers by a one-pot sequential ring opening metathesis polymerization (ROMP). PLLA-b-PS BBCPs thin-films exhibited cylindrical and lamellar morphologies depending on the relative block volume fractions, with domain sizes of 46–58 nm and periodicities of 70–102 nm. Additionally, nanoporous templates were produced by the selective etching of PLLA blocks from ordered structures. The findings described in this work provide further insight into the controlled synthesis of BBCPs leading to various possible morphologies for applications requiring large periodicities. Moreover, the rapid thin film patterning strategy demonstrated (>5 min) highlights the advantages of using PLLA-b-PS BBCP materials beyond their linear BCP analogues in terms of both dimensions achievable and reduced processing time.

Chiral Molecular Cavities of Calix[4]Crown on Au(111)

2008 ◽  
Vol 8 (11) ◽  
pp. 5702-5707 ◽  
Author(s):  
Ge-Bo Pan ◽  
Jun Luo ◽  
Qi-Yu Zheng ◽  
Li-Jun Wan
Keyword(s):  
Self Assembly ◽  
Chiral Recognition ◽  
Scanning Tunneling ◽  
Racemic Mixture ◽  
Tunneling Microscopy ◽  
Geometrical Structures ◽  
Simple Method ◽  
Ordered Structures ◽  
Ordered Arrays ◽  
Stm Images

Well-ordered arrays of chiral molecular cavities have been constructed by self-assembly of inherently chiral calix[4]crown on Au(111) in 0.1 M HClO4 solution and investigated by scanning tunneling microscopy (STM). The chiral features are clearly observed in high resolution STM images. It is found that the adsorption of the two enantiomers results in the same ordered structures with upright orientation on Au(111). Moreover, only phase separation has been observed for the racemic mixture of the two enantiomers in the experiment. This is mainly due to the weak molecule-substrate interaction as well as asymmetric geometrical structures of the two enantiomers. The present study provides a simple method for construction of ordered arrays of chiral molecular cavities, which are of potential in chemical sensors, chiral recognition, and nonlinear optics.

scholarly journals Self-assembly of hierarchically ordered structures in DNA nanotube systems

2016 ◽  
Vol 18 (5) ◽  
pp. 055001 ◽  
Author(s):  
Martin Glaser ◽  
Jörg Schnauß ◽  
Teresa Tschirner ◽  
B U Sebastian Schmidt ◽  
Maximilian Moebius-Winkler ◽  
...  
Keyword(s):  
Self Assembly ◽  
Ordered Structures ◽  
Dna Nanotube

scholarly journals Dual self-assembly of supramolecular peptide nanotubes to provide stabilisation in water

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Julia Y. Rho ◽  
Henry Cox ◽  
Edward D. H. Mansfield ◽  
Sean H. Ellacott ◽  
Raoul Peltier ◽  
...  
Keyword(s):  
Self Assembly ◽  
Supramolecular Assembly ◽  
Ordered Structures ◽  
Peptide Bonds ◽  
Self Assembling ◽  
Peptide Hydrogen ◽  
Aqueous Conditions ◽  
Β Sheet ◽  
Peptide Core ◽  
Hydrogen Bonded

Abstract Self-assembling peptides have the ability to spontaneously aggregate into large ordered structures. The reversibility of the peptide hydrogen bonded supramolecular assembly make them tunable to a host of different applications, although it leaves them highly dynamic and prone to disassembly at the low concentration needed for biological applications. Here we demonstrate that a secondary hydrophobic interaction, near the peptide core, can stabilise the highly dynamic peptide bonds, without losing the vital solubility of the systems in aqueous conditions. This hierarchical self-assembly process can be used to stabilise a range of different β-sheet hydrogen bonded architectures.

Enzyme-Mediated Self-Assembly of Highly Ordered Structures From Disordered Proteins

2008 ◽  
Author(s):  
Ahmad Athamneh ◽  
Justin Barone
Keyword(s):  
Self Assembly ◽  
Amyloid Fibrils ◽  
Prion Diseases ◽  
Wheat Gluten ◽  
Disordered Proteins ◽  
X Ray Diffraction ◽  
Ordered Structures ◽  
Wide Range ◽  
Trypsin Hydrolysis ◽  
Hydrolysis Of

Trypsin hydrolysis of wheat gluten produced glutamine-rich short peptides with a tendency to self-assemble into supermolecular structures extrinsic to native wheat gluten. Fourier transform infrared and X-ray diffraction data suggested that the new structures formed resembled that of cross-β amyloid fibrils found in some insect silk and implicated in prion diseases. The superstructures were about 10 μm in diameter with clear right-handed helical configuration and appeared to be bundles of smaller fibrils of about 63 nm in diameter. Results demonstrate the potential for utilizing cheap protein sources and natural mechanisms of protein self-assembly to design advanced nanomaterials that can provide a wide range of structural and chemical functionality.

Polymerization of dopamine accompanying its coupling to induce self-assembly of block copolymer and application in drug delivery

2020 ◽  
Vol 11 (16) ◽  
pp. 2811-2821 ◽  
Author(s):  
Yudian Qiu ◽  
Zongyuan Zhu ◽  
Yalei Miao ◽  
Panke Zhang ◽  
Xu Jia ◽  
...  
Keyword(s):  
Drug Delivery ◽  
Block Copolymer ◽  
Self Assembly ◽  
The Self ◽  
Ordered Structures

The polymerization of dopamine and its coupling occur in succession, which synergistically induces the self-assembly of block copolymer to yield ordered structures, including micelles and vesicles.

THEORY–EXPERIMENT RELATIONSHIP OF THE "SHRINKING HOT GIANT" ROAD OF DYNAMIC FULLERENE SELF-ASSEMBLY IN HOT CARBON VAPOR

NANO ◽  
2007 ◽  
Vol 02 (01) ◽  
pp. 21-30 ◽  
Author(s):  
S. IRLE ◽  
G. ZHENG ◽  
Z. WANG ◽  
K. MOROKUMA
Keyword(s):  
Formation Mechanism ◽  
Self Assembly ◽  
Density Functional ◽  
Dissipative Structures ◽  
Model Systems ◽  
Irreversible Processes ◽  
Fullerene Cage ◽  
Carbon Vapor ◽  
Assembly Mechanism ◽  
Cage Size

Though subject to intensive studies, the formation mechanism of buckminsterfullerene C 60 and related higher fullerenes has long evaded discovery. To elucidate their atomistic self-assembly mechanism, we have performed high-temperature quantum chemical molecular dynamics simulations on carbon vapor model systems initially consisting of C 2 molecules. Our simulations reveal a coherent mechanism how highly ordered fullerene cages naturally self-assemble under nonequilibrium conditions, following a series of irreversible processes from the polymerization of C 2 molecules to vibrationally excited giant fullerenes, which then shrink by C 2 evaporation down to the smallest spherical, isolated pentagon rule obeying species C 70 and C 60 as the smallest and kinetically most stable species of the shrinking process. We show that the potential energy surface associated with giant fullerene cage growth, measured by an average cluster curvature, is downhill all the way, and in agreement with high-level energetics from density functional theory. This fullerene formation mechanism is a good example of dynamic self-assembly leading to dissipative structures far from thermodynamic equilibrium, and the "shrinking hot giant" road provides a natural explanation for the observed cage size distributions in a random optimization process consistent with several important experimental observations.

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