scholarly journals SORTING OF MESOSCOPIC PARTICLES DRIVEN THROUGH PERIODIC POTENTIAL LANDSCAPES

2006 ◽  
Vol 20 (23) ◽  
pp. 1427-1442 ◽  
Author(s):  
A. M. LACASTA ◽  
M. KHOURY ◽  
J. M. SANCHO ◽  
KATJA LINDENBERG
Keyword(s):  
Particle Size ◽  
Numerical Simulations ◽  
Optical Tweezers ◽  
Colloidal Particles ◽  
Periodic Potential ◽  
Materials Science ◽  
Periodic Array ◽  
System Parameters ◽  
Unified View ◽  
Particle Characteristic

Sorting of colloidal particles of different sizes is of importance in the transport and delivery of such particles in biological, materials science, and other technological contexts. A successful methodology involves the flow of a mixture of particles over designer surfaces presenting a periodic array of traps (optical tweezers) or microfabricated obstacles. The trajectories of the particles over these surfaces deviate from the direction of flow as the particles are attracted (traps) or repelled (obstacles) by the features of the landscape. The deviation of the particles from that of the flow depends on particle size (or on some other particle characteristic) and hence the particles can be sorted according to trajectory direction. On the basis of extensive numerical simulations, we present a unified view of these methodologies and discuss the effects of system parameters such as the magnitude and direction of the flow on the sorting efficacy.

Single particle states of colloidal particles in 2D periodic potentials

Soft Matter ◽  
2018 ◽  
Vol 14 (19) ◽  
pp. 3684-3688 ◽  
Author(s):  
E. Sarmiento-Gómez ◽  
J. A. Rivera-Morán ◽  
J. L. Arauz-Lara
Keyword(s):  
Particle Size ◽  
Single Particle ◽  
Colloidal Particles ◽  
Periodic Array ◽  
Potential Wells ◽  
Periodic Potentials

Colloidal particles when subjected to a periodic array of potential wells are observed to adopt discrete stable configurations depending on the particle size/array wavelength ratio.

Stability of a Binary Colloidal Suspension and its effect on Colloidal Processing

1989 ◽  
Vol 155 ◽  
Author(s):  
Wan V. Shih ◽  
Wei-Heng Shih ◽  
Jun Liu ◽  
Ilhan A. Aksay
Keyword(s):  
Particle Size ◽  
Hard Sphere ◽  
Colloidal Particles ◽  
Colloidal Suspension ◽  
Fluid Phase ◽  
Ceramic Processing ◽  
Colloidal Processing ◽  
Interparticle Interactions ◽  
The Stability ◽  
Binary Suspension

The stability of a colloidal suspension plays an important role in colloidal processing of materials. The stability of the colloidal fluid phase is especially vital in achieving high green densities. By colloidal fluid phase, we refer to a phase in which colloidal particles are well separated and free to move about by Brownian motion, By controlling parameters such as pH, salt concentration, and surfactants, one can achieve high packing (green) densities in the repulsive regime where the suspension is well dispersed as a colloidal fluid, and low green densities in the attractive regime where the suspensions are flocculated [1,2]. While there is increasing interest in using bimodal suspensions to improve green densities, neither the stability of a binary suspension as a colloidal fluid nor the stability effects on the green densities have been studied in depth as yet. Traditionally, the effect of using bimodal-particle-size distribution has only been considered in terms of geometrical packing developed by Furnas and others [3,4]. This model is a simple packing concept and is used and useful for hard sphere-like repulsive interparticle interactions. With the advances in powder technology, smaller and smaller particles are available for ceramic processing. Thus, the traditional consideration of geometrial packing for the green densities of bimodal suspensions may not be enough. The interaction between particles must be taken into account.

scholarly journals Probing roto-translational diffusion of small anisotropic colloidal particles with a bright-field microscope

2021 ◽  
Vol 44 (4) ◽  
Author(s):  
Fabio Giavazzi ◽  
Antara Pal ◽  
Roberto Cerbino
Keyword(s):  
Particle Size ◽  
Rotational Motion ◽  
Colloidal Particles ◽  
Aqueous Suspension ◽  
Translational Motion ◽  
Translational Diffusion ◽  
Experimental Demonstration ◽  
Bright Field ◽  
Microscopic Scale ◽  
Bright Field Microscopy

Abstract Soft and biological materials are often composed of elementary constituents exhibiting an incessant roto-translational motion at the microscopic scale. Tracking this motion with a bright-field microscope becomes increasingly challenging when the particle size becomes smaller than the microscope resolution, a case which is frequently encountered. Here we demonstrate squared-gradient differential dynamic microscopy (SG-DDM) as a tool to successfully use bright-field microscopy to extract the roto-translational dynamics of small anisotropic colloidal particles, whose rotational motion cannot be tracked accurately in direct space. We provide analytical justification and experimental demonstration of the method by successful application to an aqueous suspension of peanut-shaped particles. Graphic abstract

High Uniformity of ZnO Nanoparticles Synthesized by Surfactant-Assisted Solvothermal Technique

2015 ◽  
Vol 1131 ◽  
pp. 43-48 ◽  
Author(s):  
Atthaphon Maneedaeng
Keyword(s):  
Particle Size ◽  
Zno Nanoparticles ◽  
Colloidal Particles ◽  
Hydrothermal Reaction ◽  
Solvothermal Reaction ◽  
Exciton Peak ◽  
Solvothermal Technique ◽  
Tauc Plot ◽  
High Uniformity ◽  
Surfactant Assisted

The aim of this study is to develop the synthetic procedure of Zinc Oxide (ZnO) nanoparticles by using surfactant-assisted solvothermal technique in order to produce highly uniform nanosize of ZnO particles. The solvothermal reaction evidently produces smaller ZnO particle sizes compared with those obtained from hydrothermal reaction. The zwitterionic surfactant is employed in this work and it typically works well under extremely conditions i.e. high pH levels, strong electrolytes, and high temperature. The key success of surfactant utilization in the solvothermal reaction is to create reversed micelles which act as nanoreactors or templates. Because micelle consist of polar cores that may occupy a finite amount of water forming a water pool for ZnO nanomaterial synthesis. Synthesized ZnO nanoparticles were obtained from solvothermal reaction at 180°C and 18 hours in a hydrothermal reactor. The ZnO colloidal particles were separated by paper filter and cellulose nitrate membrane, respectively. The XRD pattern shows that the structure of the synthesized ZnO nanoparticles is hexagonal wurtzite and the use of surfactant does not interfere the crystal growth and structure. The particle size distribution reveals a high uniform ZnO nanoparticles obtained via this method. The UV absorption spectrum of ZnO nanoparticles synthesized by this method presents exciton peak at approximate value of 365 nanometers. The energy band gap determined by Tauc plot is 3.31 eV. Moreover, TEM images confirm the particle size consistency showing the morphology of the prepared ZnO nanoparticles.

Fractal Basin Boundaries and Chaotic Motions in Spring-Pendulum System

2003 ◽  
Author(s):  
Aria Alasty ◽  
Rasool Shabani
Keyword(s):  
Numerical Simulations ◽  
Multiple Scales ◽  
Basins Of Attraction ◽  
Chaotic Attractors ◽  
Global Behavior ◽  
Chaotic Motions ◽  
Pendulum System ◽  
Fractal Basin Boundaries ◽  
System Parameters ◽  
Basin Boundaries

This study investigates chaotic response in the spring-pendulum system. In this system beside of strange attractors, multiple regular attractors may coexist for some values of system parameters, where it is important to study the global behavior of the system using the basin boundaries of the attractors. Multiple scales method is used to distinguish the regions of stable and unstable attractors. In unstable regions, bifurcation diagram and poincare´ maps are used to study the existence of quasi-periodic and chaotic attractors. Results show that the jumping phenomena may occur when multiple regular attractors exist and for this case fractal basins of attraction are developed using numerical simulations.

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