scholarly journals High-aspect-ratio mushroom-like silica nanopillars immersed in air: epsilon-near-zero metamaterials mediated by a phonon-polaritonic anisotropy

RSC Advances ◽  
2019 ◽  
Vol 9 (29) ◽  
pp. 16431-16438
Author(s):  
Kota Ito ◽  
Yuri Yamada ◽  
Atsushi Miura ◽  
Hideo Iizuka
Keyword(s):  
Block Copolymers ◽  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Self Assembly ◽  
Infrared Range ◽  
Mid Infrared ◽  
Zero Response ◽  
Epsilon Near Zero

High-aspect-ratio mushroom-like silica nanopillars fabricated from self-assembly of block-copolymers exhibit a uniaxial epsilon-near-zero response in the mid-infrared range.

Cooperative Self-Assembly of Pyridine-2,6-Diimine-Linked Macrocycles into Mechanically Robust Nanotubes

2019 ◽  
Author(s):  
Michael J. Strauss ◽  
Darya Asheghali ◽  
Austin Evans ◽  
Rebecca Li ◽  
Anton Chavez ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Self Assembly ◽  
Gel Permeation Chromatography ◽  
Synthetic Polymers ◽  
Young’S Moduli ◽  
Structural Rigidity ◽  
Assembly Mechanism ◽  
Low Dimensionality ◽  
Harsh Conditions

<p>Nanotubes assembled from macrocyclic precursors offer a unique combination of low dimensionality, structural rigidity, and distinct interior and exterior microenvironments. Usually the weak stacking energies of macrocycles limit the length or strength of the resultant nanotubes. Imine-linked macrocycles were recently found to assemble into high-aspect ratio (>10<sup>3</sup>), lyotropic nanotubes in the presence of excess acid. Yet these harsh conditions are incompatible with many functional groups and processing methods, and lower acid loadings instead catalyze macrocycle degradation. Here we report pyridine-2,6-diimine-linked macrocycles that assemble into high-aspect ratio nanotubes in the presence of less than 1 equiv of CF<sub>3</sub>CO<sub>2</sub>H per macrocycle. Analysis by gel permeation chromatography and fluorescence spectroscopy revealed a cooperative self-assembly mechanism. Nanofibers obtained by touch-spinning the pyridinium-based nanotubes exhibit Young’s moduli of 1.48 GPa, which exceeds that of many synthetic polymers and biological filaments. These findings will enable the design of structurally diverse nanotubes from synthetically accessible macrocycles. </p>

Photopolymerization-assisted self-assembly as a strategy to obtain a dispersion of very high aspect ratio nanostructures in a polystyrene matrix

2019 ◽  
Vol 112 ◽  
pp. 704-713 ◽  
Author(s):  
Ú.M. Montoya Rojo ◽  
C.C. Riccardi ◽  
M.D. Ninago ◽  
A.E. Ciolino ◽  
M.A. Villar ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Self Assembly ◽  
Polystyrene Matrix ◽  
Very High

Cooperative Self-Assembly of Pyridine-2,6-Diimine-Linked Macrocycles into Mechanically Robust Nanotubes

2019 ◽  
Author(s):  
Michael J. Strauss ◽  
Darya Asheghali ◽  
Austin Evans ◽  
Rebecca Li ◽  
Anton Chavez ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Self Assembly ◽  
Gel Permeation Chromatography ◽  
Synthetic Polymers ◽  
Young’S Moduli ◽  
Structural Rigidity ◽  
Assembly Mechanism ◽  
Low Dimensionality ◽  
Harsh Conditions

<p>Nanotubes assembled from macrocyclic precursors offer a unique combination of low dimensionality, structural rigidity, and distinct interior and exterior microenvironments. Usually the weak stacking energies of macrocycles limit the length or strength of the resultant nanotubes. Imine-linked macrocycles were recently found to assemble into high-aspect ratio (>10<sup>3</sup>), lyotropic nanotubes in the presence of excess acid. Yet these harsh conditions are incompatible with many functional groups and processing methods, and lower acid loadings instead catalyze macrocycle degradation. Here we report pyridine-2,6-diimine-linked macrocycles that assemble into high-aspect ratio nanotubes in the presence of less than 1 equiv of CF<sub>3</sub>CO<sub>2</sub>H per macrocycle. Analysis by gel permeation chromatography and fluorescence spectroscopy revealed a cooperative self-assembly mechanism. Nanofibers obtained by touch-spinning the pyridinium-based nanotubes exhibit Young’s moduli of 1.48 GPa, which exceeds that of many synthetic polymers and biological filaments. These findings will enable the design of structurally diverse nanotubes from synthetically accessible macrocycles. </p>

Formation of High-Aspect-Ratio Helical Nanorods via Chiral Self-Assembly of Fullerodendrimers

2014 ◽  
Vol 5 (5) ◽  
pp. 929-934 ◽  
Author(s):  
Andrew J. Hilmer ◽  
Darin O. Bellisario ◽  
Steven Shimizu ◽  
Thomas P. McNicholas ◽  
Qing Hua Wang ◽  
...  
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Self Assembly

scholarly journals Fabrication of silicon nanotip arrays with high aspect ratio by cesium chloride self-assembly and dry etching

AIP Advances ◽  
2014 ◽  
Vol 4 (3) ◽  
pp. 031335 ◽  
Author(s):  
Xinshuai Zhang ◽  
Jing Liu ◽  
Bo Wang ◽  
Tianchong Zhang ◽  
Futing Yi
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Self Assembly ◽  
Cesium Chloride ◽  
Dry Etching ◽  
Silicon Nanotip

High Aspect Ratio Polymer Micro/Nano-Structure Manufacturing Using Nanoembossing, Nanomolding and Directed Self-Assembly

2003 ◽  
Author(s):  
Metin Sitti
Keyword(s):  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Self Assembly ◽  
Scanning Tunneling ◽  
Nano Structure ◽  
Liquid Polymer ◽  
Dry Adhesives ◽  
Liquid Polymers ◽  
Assembly Technique ◽  
Dc Electric Field

This paper proposes three methods to fabricate synthetic gecko foot-hair high aspect ratio polymer micro/nanostructures. In the first method, nano-robotically indented templates are molded with liquid polymers, and the cured polymer is peeled off or etched away. Atomic force microscope and scanning tunneling microscope probe tips are used to emboss/indent flat wax surfaces, and silicone rubber micro/nano-bump structures are demonstrated. The second one uses a self-organized polycarbonate nano-pore membrane as the molding template. PDMS is molded into these micro/nano-pores under vacuum, and 1:2 and 1:9 aspect ratio pillar structures with 5 micron and 0.6 micron diameters are manufactured successfully. Finally, a directed self-assembly technique is proposed to grow regularly spaced and oriented micro/nano-pillars. Here, instability of a liquid polymer thinfilm under a DC electric field is used to grow nano-pillars, and stretching and shearing of the grown hairs enable high aspect ratio and oriented hair structures. These hair structures will be utilized as novel biomimetic dry adhesives in future miniature space and surgical robot feet.

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