scholarly journals Shaping in the Third Direction; Synthesis of Patterned Colloidal Crystals by Polyester Fabric-Guided Self-Assembly

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4081
Author(s):  
Ion Sandu ◽  
Claudiu Teodor Fleaca ◽  
Florian Dumitrache ◽  
Bogdan Alexandru Sava ◽  
Iuliana Urzica ◽  
...  
Keyword(s):  
Self Assembly ◽  
Colloidal Crystal ◽  
Ambient Pressure ◽  
Single Layer ◽  
Polyester Fabric ◽  
Unit Cell ◽  
Thick Wall ◽  
Dimensional Sphere ◽  
Triangular Prism ◽  
Shape Pattern

A polyester fabric with rectangular openings was used as a sacrificial template for the guiding of a sub-micron sphere (polystyrene (PS) and silica) aqueous colloid self-assembly process during evaporation as a patterned colloidal crystal (PCC). This simple process is also a robust one, being less sensitive to external parameters (ambient pressure, temperature, humidity, vibrations). The most interesting feature of the concave-shape-pattern unit cell (350 μm × 400 μm × 3 μm) of this crystal is the presence of triangular prisms at its border, each prism having a one-dimensional sphere array at its top edge. The high-quality ordered single layer found inside of each unit cell presents the super-prism effect and left-handed behavior. Wider yet elongated deposits with ordered walls and disordered top surfaces were formed under the fabric knots. Rectangular patterning was obtained even for 20 μm PS spheres. Polyester fabrics with other opening geometries and sizes (~300–1000 μm) or with higher fiber elasticity also allowed the formation of similar PCCs, some having curved prismatic walls. A higher colloid concentration (10–20%) induces the formation of thicker walls with fiber-negative replica morphology. Additionally, thick-wall PCCs (~100 μm) with semi-cylindrical morphology were obtained using SiO2 sub-microspheres and a wavy fabric. The colloidal pattern was used as a lithographic mask for natural lithography and as a template for the synthesis of triangular-prism-shaped inverted opals.

scholarly journals Independently Tunable Multipurpose Absorber with Single Layer of Metal-Graphene Metamaterials

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 284
Author(s):  
Chen Han ◽  
Renbin Zhong ◽  
Zekun Liang ◽  
Long Yang ◽  
Zheng Fang ◽  
...  
Keyword(s):  
Energy Harvesting ◽  
Fermi Level ◽  
Potential Application ◽  
Single Layer ◽  
Wide Band ◽  
Metamaterial Absorber ◽  
Unit Cell ◽  
Perfect Absorption ◽  
Solar Energy Harvesting ◽  
Band Absorption

This paper reports an independently tunable graphene-based metamaterial absorber (GMA) designed by etching two cascaded resonators with dissimilar sizes in the unit cell. Two perfect absorption peaks were obtained at 6.94 and 10.68 μm with simple single-layer metal-graphene metamaterials; the peaks show absorption values higher than 99%. The mechanism of absorption was analyzed theoretically. The independent tunability of the metamaterial absorber (MA) was realized by varying the Fermi level of graphene under a set of resonators. Furthermore, multi-band and wide-band absorption were observed by the proposed structure upon increasing the number of resonators and resizing them in the unit cell. The obtained results demonstrate the multipurpose performance of this type of absorber and indicate its potential application in diverse applications, such as solar energy harvesting and thermal absorbing.

Buckling of a Confined Colloidal Crystal

1992 ◽  
Vol 290 ◽  
Author(s):  
T. Chou ◽  
D. R. Nelson
Keyword(s):  
Colloidal Crystal ◽  
Single Layer ◽  
Colloidal Suspensions ◽  
Plate Separation

AbstractThe behavior of colloidal suspensions confined between two plates narrowly spaced is examined. When plate separations are small, only one layer of particles can be confined; however, as plate separation is increased, multiple layers will eventually form. These layers can exist in a variety of structures depending on the energetics of packing. We examine the unstable modes which form as a single layer buckles on its way to forming two layers. Three ordered states are found; which one is selected depends on the form of the interparticle and wall potentials.

Interface–gravity joint self-assembly behaviors of P(St-MAA) colloidal microspheres on polyester fabric substrates

2017 ◽  
Vol 52 (9) ◽  
pp. 5060-5071 ◽  
Author(s):  
Liqin Chai ◽  
Lan Zhou ◽  
Guojin Liu ◽  
Yichen Li ◽  
Qinguo Fan ◽  
...  
Keyword(s):  
Self Assembly ◽  
Polyester Fabric

scholarly journals Nanostructural self-assembly of iridescent feather barbules through depletion attraction of melanosomes during keratinization

2011 ◽  
Vol 9 (69) ◽  
pp. 734-743 ◽  
Author(s):  
Rafael Maia ◽  
Regina H. F. Macedo ◽  
Matthew D. Shawkey
Keyword(s):  
Self Assembly ◽  
Light And Electron Microscopy ◽  
Single Layer ◽  
Metabolic Cost ◽  
Condition Dependence ◽  
Developmental Pathway ◽  
Ordered Arrays ◽  
Cellular Control ◽  
Ornamental Traits ◽  
Nanostructural Organization

Avian plumage colours are model traits in understanding the evolution of sexually selected ornamental traits. Paradoxically, iridescent structural colours, probably the most dazzling of these traits, remain the most poorly understood. Though some data suggest that expression of bright iridescent plumage colours produced by highly ordered arrays of melanosomes and keratin is condition-dependent, almost nothing is known of their ontogeny and thus of any developmental mechanisms that may be susceptible to perturbation. Here, we use light and electron microscopy to compare the ontogeny of iridescent male and non-iridescent female feathers in blue-black grassquits. Feather barbules of males contain a single layer of melanosomes bounded by a thin layer of keratin-producing blue iridescent colour, while those of females contain disorganized melanosomes and no outer layer. We found that nanostructural organization of male barbules occurs late in development, following death of the barbule cell, and is thus unlikely to be under direct cellular control, contrary to previous suggestions. Rather, organization appears to be caused by entropically driven self-assembly through depletion attraction forces that pin melanosomes to the edge of barbule cells and to one another. These forces are probably stronger in developing barbules of males than of females because their melanosomes are (i) larger, (ii) more densely packed, and (iii) more homogeneously distributed owing to the more consistent shape of barbules during keratinization. These data provide the first proposed developmental pathway for iridescent plumage colours, and suggest that any condition dependence of iridescent barbules is likely driven by factors other than direct metabolic cost.

scholarly journals Synthesis of magnetic mesoporous titania colloidal crystals through evaporation induced self-assembly in emulsion as effective and recyclable photocatalysts

2015 ◽  
Vol 17 (41) ◽  
pp. 27653-27657 ◽  
Author(s):  
Jeffrey E. Chen ◽  
Hong-Yuan Lian ◽  
Saikat Dutta ◽  
Saad M. Alshehri ◽  
Yusuke Yamauchi ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Magnetic Properties ◽  
Self Assembly ◽  
Colloidal Crystal ◽  
Colloidal Crystals ◽  
Mesoporous Titania ◽  
Evaporation Induced Self Assembly

This study illustrates the directed self-assembly of mesoporous TiO2 with magnetic properties due to its colloidal crystal structure with Fe3O4.

A Wideband, Single-Layer Reflectarray Exploiting a Polarization Rotating Unit Cell

2019 ◽  
Vol 67 (2) ◽  
pp. 872-883 ◽  
Author(s):  
Hung Luyen ◽  
Zhe Yang ◽  
Meng Gao ◽  
John H. Booske ◽  
Nader Behdad
Keyword(s):  
Single Layer ◽  
Unit Cell

scholarly journals Dynamic porous property in a new heterometallic supramolecular compound

2014 ◽  
Vol 70 (a1) ◽  
pp. C1474-C1474
Author(s):  
Patrice Kenfack ◽  
Emmanuel Wenger ◽  
Slimane Dahaoui ◽  
John Lambi ◽  
Pierrick Durand ◽  
...  
Keyword(s):  
Hydrogen Bonds ◽  
Self Assembly ◽  
Water Clusters ◽  
Chair Conformation ◽  
Unit Cell ◽  
Supramolecular Compounds ◽  
Multifunctional Compounds ◽  
Potential Applications ◽  
One Step ◽  
Mean Vector

Supramolecular compounds have attracted considerable interest to chemists, physicists and materials scientists due to their fascinating structures and potential applications as porosity [1-3] but one of the most appealing aims today, is to build multifunctional compounds. We are interested to rationalize the synthesis of porous heterometallic compounds by self- assembly via hydrogen bonds. In this communication, we present a stacked 2D Catena-{Co(amp)3Cr(ox)3.6H2O} (amp = 2-picolylamine, ox=oxalate). It is built by layers in which both (Co(amp)3+ (D) and Cr(ox)3- ( A)) ionic units are linked in a repeating DADADA...pattern along both the a and c axis with four and two hydrogen bonds respectively. These layers host very well resolved dodecameric discrete ring water clusters (R12) built by six independent molecules located around the centrosymmetric Wyckoff position's of the P21/n space group in which the compound crystallizes. The clusters are ranged along the [001] direction, occupy 807.6 Å3 (23.9%) of the unit cell and have a chair conformation via 10 hydrogen bonds. The dehydration process of the compound occurs in one step around 77oC and the dehydrated compound remains crystalline although all framework atoms move by 2.25 Å along a mean vector (dm= 2.21 i + 0.17 j + 0.37 k) during the process. The unit cell is then reduced by 12.34 % along a, 12.22% along b and 2. 03% along c reducing V by 22.03%. By exposure to air, the regeneration of the compound needs 90 min, following the first kinetic Avrami's model.

Self-Assembly Growth and Size Control of Silver Nanocrystals for Nonvolatile Memory Applications

2009 ◽  
Vol 610-613 ◽  
pp. 585-590 ◽  
Author(s):  
Li Wang ◽  
Hong Fang Sun ◽  
Hui Hua Zhou ◽  
Jing Zhu
Keyword(s):  
Self Assembly ◽  
Nonvolatile Memory ◽  
Single Layer ◽  
Size Control ◽  
Transmission Electron ◽  
Sputtering Power ◽  
High Uniformity ◽  
Memory Applications ◽  
Magnetic Sputtering ◽  
The Relationship

A film with a single-layer of size controlled silver nanocrystals embedded in silicon dioxide (SiO2) dielectric film by magnetic sputtering has been fabricated for nonvolatile memory applications. The effects of sputtering power, deposition time and substrate temperature on Ag nanocrystals formation were investigated. Transmission electron microscopy (TEM) images showed the as-prepared Ag nanocrystals had high uniformity in their size and distribution. The relationship between Ag nanocrystal size, density and electron storage capability as well as date retention time has been discussed.

Rheological Aspects of Multilayered Thick-Wall Polymeric Pipes under the Influence of Internal Pressure

2020 ◽  
Vol 869 ◽  
pp. 209-217
Author(s):  
Serdar B. Yazyev ◽  
Stepan Litvinov ◽  
Anastasia E. Dudnik ◽  
Irina Doronkina
Keyword(s):  
Internal Pressure ◽  
Single Layer ◽  
Thermal Conditions ◽  
Thick Wall ◽  
Rheological Parameters ◽  
The Finite Element Method ◽  
One Dimensional ◽  
Cyclic Temperature ◽  
Temperature Dependences ◽  
Pvc Pipe

Rheologic of a polymer pipe from cyclic temperature and internal pressure in one-dimensional and two-dimensional formulations is considered. The resulting equations of the finite element method allow one to calculate both single-layer and multilayer thick-walled pipes taking into account creep. In the calculation, the temperature dependences of the elastic and rheological parameters of polymer pipes were used. The effect of variable thermal conditions on the VAT of a PVC pipe is investigated. It has been established that under unsteady thermal conditions, stresses can occur significantly higher than in a stationary temperature field. This is explained by the fact that polymers have a component of deformation that is lagging in phase from stresses (highly elastic deformation).

scholarly journals Modified Minkowski Fractal Unit Cell for Reflectarrays with Low Sensitivity to Mutual Coupling Effects

2019 ◽  
Vol 2019 ◽  
pp. 1-11 ◽  
Author(s):  
Sandra Costanzo ◽  
Francesca Venneri ◽  
Giuseppe Di Massa
Keyword(s):  
Mutual Coupling ◽  
Coupling Effect ◽  
Single Layer ◽  
Unit Cell ◽  
Phase Curve ◽  
Lower Sensitivity ◽  
Coupling Effects ◽  
Infinite Array ◽  
Low Sensitivity ◽  
Phase Design

A single-layer miniaturized reflectarray element with low sensitivity to mutual coupling effects of surrounding elements is presented in this paper. The configuration is proposed to preserve the effectiveness of the infinite array approach in those applications requiring reflectarrays with very small interelement spacing. The inherent ability of the proposed geometry to be adopted in highly miniaturized cells is demonstrated through an extensive analysis of mutual coupling effects on reflectarray phase design curves. In order to prove the independence of the proposed cell to mutual coupling effect, the phase curve variations due to the presence of different surrounding elements with respect to the case of identical cells are evaluated using the well-known extended local periodicity method. Small and negligible mutual coupling errors are retrieved for the proposed miniaturized unit cell, thus demonstrating lower sensitivity to mutual coupling adverse effects.

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