scholarly journals Improvement of the Centrifugal Force in Gravity Driven Method for the Fabrication of Highly Ordered and Submillimeter-Thick Colloidal Crystal

Polymers ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 692
Author(s):  
Ting-Hui Chen ◽  
Shuan-Yu Huang ◽  
Syuan-Yi Huang ◽  
Jia-De Lin ◽  
Bing-Yau Huang ◽  
...  
Keyword(s):  
Centrifugal Force ◽  
Modified Gravity ◽  
Colloidal Solution ◽  
Colloidal Crystal ◽  
Colloidal Crystals ◽  
Silica Particles ◽  
Gravity Method ◽  
Structural Order ◽  
Silica Solution ◽  
Gravity Driven

In this paper, we propose a modified gravity method by introducing centrifugal force to promote the stacking of silica particles and the order of formed colloidal crystals. In this method, a monodispersed silica colloidal solution is filled into empty cells and placed onto rotation arms that are designed to apply an external centrifugal force to the filled silica solution. When sample fabrication is in progress, silica particles are forced toward the edges of the cells. The number of defects in the colloidal crystal decreases and the structural order increases during this process. The highest reflectivity and structural order of a sample was obtained when the external centrifugal force was 18 G. Compared to the samples prepared using the conventional stacking method, samples fabricated with centrifugal force possess higher reflectivity and structural order. The reflectivity increases from 68% to 90%, with an increase in centrifugal force from 0 to 18 G.

scholarly journals Position Dependence of Emission Wavelength of a SiO2 Colloidal Photonic-Crystal Laser

Polymers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 802 ◽  
Author(s):  
Ting-Hui Chen ◽  
Bing-Yau Huang ◽  
Chie-Tong Kuo
Keyword(s):  
Photonic Crystal ◽  
Colloidal Crystal ◽  
Threshold Energy ◽  
Silica Particles ◽  
Wavelength Tunable ◽  
Coffee Ring ◽  
Crystal Laser ◽  
Coffee Ring Effect ◽  
Photonic Crystal Laser ◽  
Ring Effect

In this paper, a wavelength tunable colloidal-crystal laser with monodispersed silica particles was demonstrated. Silica particles were synthesized through the modified Stöber process and self-assembled into the colloidal photonic-crystal structure, which was then used to form the optic cavity of a wavelength tunable laser device. Due to Bragg’s diffraction of the colloidal photonic-crystal and the coffee ring effect, the forbidden energy gap of light varied with different lattice sizes at different positions of the colloidal photonic-crystal. When the pumping pulsed laser irradiated on the gain medium of the sample, the fluorescence was restricted and enhanced by the colloidal photonic-crystal. Lasing emission with a single peak occurred when the energy of the pumping laser exceeded the threshold energy. The threshold energy and the full-width at half-maximum (FWHM) of the proposed laser were 7.63 µJ/pulse and 2.88 nm, respectively. Moreover, the lasing wavelength of the colloidal photonic-crystal laser could be tuned from 604 nm to 594 nm, corresponding to the various positions in the sample due to the coffee ring effect.

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.

scholarly journals Bioinspired hydrogel microfibres colour-encoded with colloidal crystals

2019 ◽  
Vol 6 (9) ◽  
pp. 1938-1943 ◽  
Author(s):  
Zhi-Jun Meng ◽  
Jing Zhang ◽  
Xu Deng ◽  
Ji Liu ◽  
Ziyi Yu ◽  
...  
Keyword(s):  
Colloidal Crystal ◽  
Colloidal Crystals

The integration of microfluidic spinning and colloidal crystal microdots enable the colour-encoded hydrogel microfibres with facile and flexible manipulation of the encoding.

scholarly journals Convenient and Efficient Fabrication of Colloidal Crystals Based on Solidification-Induced Colloidal Assembly

Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 575 ◽  
Author(s):  
Ting Shao ◽  
Laixi Sun ◽  
Chun Yang ◽  
Xin Ye ◽  
Shufan Chen ◽  
...  
Keyword(s):  
Driving Force ◽  
Crystallization Process ◽  
Colloidal Crystal ◽  
Colloidal Crystals ◽  
Magnetic Interaction ◽  
Colloidal Assembly ◽  
Water Suspension ◽  
Colloidal Crystallization ◽  
New Strategy ◽  
Crystal Grains

The simple yet efficient and versatile fabrication of colloidal crystals was investigated based on the solidification-induced colloidal crystallization process with particle/water suspension as precursor. The resulting colloidal crystals were constituted by crystal grains with sizes ranging from several tens of micrometers to a few millimeters. Each of the grains had a close-hexagonal array of colloids, which endowed the bulk colloidal crystal powders with some specific optical properties. The freezing of water was shown as the major driving force to form colloidal crystal grains, which supersaturated the solution with nanoparticles and thus induced the formation and growth of colloidal crystal seeds. This process is intrinsically different from those conventional methods based on shearing force, surface tension, columbic interaction or magnetic interaction, revealing a new strategy to fabricate colloidal crystals in a convenient and efficient way.

Suspensions of Silica Particles Grafted with Concentrated Polymer Brush:  A New Family of Colloidal Crystals

2006 ◽  
Vol 39 (3) ◽  
pp. 1245-1249 ◽  
Author(s):  
Kohji Ohno ◽  
Takashi Morinaga ◽  
Satoshi Takeno ◽  
Yoshinobu Tsujii ◽  
Takeshi Fukuda
Keyword(s):  
Polymer Brush ◽  
Colloidal Crystals ◽  
Silica Particles ◽  
New Family

Numerical Simulation of Natural Convection in Stationary and Rotating Cavities

2004 ◽  
Author(s):  
Zixiang Sun ◽  
Alistair Kifoil ◽  
John W. Chew ◽  
Nicholas J. Hills
Keyword(s):  
Heat Transfer ◽  
Centrifugal Force ◽  
Large Scale ◽  
Transfer Rates ◽  
Buoyancy Driven Flows ◽  
Gravity Driven ◽  
Gravity Driven Flow ◽  
Large Scale Flow ◽  
Rayleigh Numbers ◽  
Good Agreement

In compressor inter-disc cavities with a central axial throughflow it is known that the flow and heat transfer is strongly affected by buoyancy in the centrifugal force field. As a step towards developing CFD methods for such flows, buoyancy-driven flows under gravity in a closed cube and under centrifugal force in a sealed rotating annulus have been studied. Numerical simulations are compared with the experimental results of Kirkpatrick and Bohn (1986) and Bohn et al (1993). Two different CFD codes have been used and are shown to agree for the stationary cube problem. Unsteady simulations for the stationary cube show good agreement with measurements of heat transfer, temperature fluctuations, and velocity fluctuations for Rayleigh numbers up to 2 × 1010. Similar simulations for the rotating annulus also show good agreement with measured heat transfer rates. The CFD results confirm Bohn et al’s results, showing reduced heat transfer and a different Rayleigh number dependency compared to gravity-driven flow. Large scale flow structures are found to occur, at all Rayleigh numbers considered.

Structure and physical properties of colloidal crystals made of silica particles

2012 ◽  
Vol 401 ◽  
pp. 38-47 ◽  
Author(s):  
Sabine Portal-Marco ◽  
Mª Àngels Vallvé ◽  
Oriol Arteaga ◽  
Jordi Ignés-Mullol ◽  
Carles Corbella ◽  
...  
Keyword(s):  
Physical Properties ◽  
Colloidal Crystals ◽  
Silica Particles

scholarly journals Colloidal crystals of compliant microgel beads to study cell migration and mechanosensitivity in 3D

Soft Matter ◽  
2019 ◽  
Vol 15 (47) ◽  
pp. 9776-9787 ◽  
Author(s):  
Katrin Wagner ◽  
Salvatore Girardo ◽  
Ruchi Goswami ◽  
Gonzalo Rosso ◽  
Elke Ulbricht ◽  
...  
Keyword(s):  
Cell Migration ◽  
Colloidal Crystal ◽  
Colloidal Crystals ◽  
Variable Stiffness ◽  
Ecm Proteins

We present a novel 3D colloidal crystal made of polyacrylamide microgel beads with variable stiffness. The beads can be functionalized with ECM proteins and used to study mechanosensing responses of cells to varying stiffness in a 3D context.

scholarly journals Ordering of binary colloidal crystals by random potentials

Soft Matter ◽  
2020 ◽  
Vol 16 (17) ◽  
pp. 4267-4273 ◽  
Author(s):  
André S. Nunes ◽  
Sabareesh K. P. Velu ◽  
Iryna Kasianiuk ◽  
Denis Kasyanyuk ◽  
Agnese Callegari ◽  
...  
Keyword(s):  
Random Potential ◽  
Colloidal Crystal ◽  
Colloidal Crystals ◽  
Random Potentials

A random potential can control the number of defects in a binary colloidal crystal.

scholarly journals Particle analogs of electrons in colloidal crystals

Science ◽  
2019 ◽  
Vol 364 (6446) ◽  
pp. 1174-1178 ◽  
Author(s):  
Martin Girard ◽  
Shunzhi Wang ◽  
Jingshan S. Du ◽  
Anindita Das ◽  
Ziyin Huang ◽  
...  
Keyword(s):  
Colloidal Crystal ◽  
Colloidal Crystals ◽  
Insulator Transition ◽  
Metal Insulator Transition ◽  
Design Rules ◽  
Metal Insulator ◽  
Grafting Density ◽  
And Diffusion ◽  
Classical Picture

A versatile method for the design of colloidal crystals involves the use of DNA as a particle-directing ligand. With such systems, DNA-nanoparticle conjugates are considered programmable atom equivalents (PAEs), and design rules have been devised to engineer crystallization outcomes. This work shows that when reduced in size and DNA grafting density, PAEs behave as electron equivalents (EEs), roaming through and stabilizing the lattices defined by larger PAEs, as electrons do in metals in the classical picture. This discovery defines a new property of colloidal crystals—metallicity—that is characterized by the extent of EE delocalization and diffusion. As the number of strands increases or the temperature decreases, the EEs localize, which is structurally reminiscent of a metal-insulator transition. Colloidal crystal metallicity, therefore, provides new routes to metallic, intermetallic, and compound phases.

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