scholarly journals Motion of an active particle in a linear concentration gradient

2021 ◽  
Vol 33 (3) ◽  
pp. 032011
Author(s):  
Prathmesh M. Vinze ◽  
Akash Choudhary ◽  
S. Pushpavanam
2009 ◽  
Vol 11 (5) ◽  
pp. 1135-1143 ◽  
Author(s):  
Hojeong Jeon ◽  
Yongku Lee ◽  
Songwan Jin ◽  
Sangmo Koo ◽  
Chang-Soo Lee ◽  
...  

Author(s):  
Jacky S. H. Lee ◽  
Yandong Hu ◽  
Dongqing Li

Creation of concentration gradients is important in the study of biological and chemical processes that are sensitive to concentration variations. This paper presents a simple method to generate a linear concentration gradient in electroosmotic flow in microchannels with converging and diverging geometries. The method is based on the enhanced diffusive mixing inside the microchannel. By varying the converging-diverging geometries, the degree of diffusive mixing can be controlled. Different concentration gradients can be obtained by varying the applied potential and the geometry. Concentration profiles with minimal axial variations can be achieved with a deviation of 7% and 3% over a channel length of 3mm and 1mm, respectively, for a 400μm wide microchannel. Although the underlying physics and mechanisms for creating concentration profiles in a converging-diverging microchannel are the same as a T-shaped micromixer, the converging-diverging microchannel can produce desired concentration profiles in a much shorter distance (shorter by a factor of 2∼3.5 compared to a T-shape mixer). A serially connected concentration gradient generator is also realized with the ability to generate two concentration gradient ranges in the same microchannel. Numerical simulations and experiments were carried out to investigate the factors contributed to the generation of the concentration gradients.


2021 ◽  
Author(s):  
Baitao Jiang

Anisotropic porous polymeric materials fabricated from the phase separation method via spinodal decomposition are used in various practical engineering applications. Examples include anisotropic porous polymeric membranes for separation processes and holographic polymer dispersed liquid crystal films for electro-optical devices. We have studied numerically the formation of anisotropic porous polymeric materials by imposing an initial linear concentration gradient across a model polymer solution. The mathematical model is composed of the non-linear Cahn-Hilliard theory to describe spinodal decomposition dynamics, the Flory-Huggins theory for polymer solution thermodynamics, and the slow mode theory combined with the Rouse law for polymer diffusion. The computer simulations include uniform (no gradient) and non-uniform (with an initial concentration gradient) cases. For the non-uniform cases, the initial concentration gradient is placed at three different regions of polymer sample for the purpose of comparison. All the simulation results are in good agreement with published experimental observations which are reported from the applications of porous polymeric membranes. The structure development shows that an anisotropic porous morphology forms when an initial linear concentration gradient is applied to the model polymer solution.


2021 ◽  
Author(s):  
Baitao Jiang

Anisotropic porous polymeric materials fabricated from the phase separation method via spinodal decomposition are used in various practical engineering applications. Examples include anisotropic porous polymeric membranes for separation processes and holographic polymer dispersed liquid crystal films for electro-optical devices. We have studied numerically the formation of anisotropic porous polymeric materials by imposing an initial linear concentration gradient across a model polymer solution. The mathematical model is composed of the non-linear Cahn-Hilliard theory to describe spinodal decomposition dynamics, the Flory-Huggins theory for polymer solution thermodynamics, and the slow mode theory combined with the Rouse law for polymer diffusion. The computer simulations include uniform (no gradient) and non-uniform (with an initial concentration gradient) cases. For the non-uniform cases, the initial concentration gradient is placed at three different regions of polymer sample for the purpose of comparison. All the simulation results are in good agreement with published experimental observations which are reported from the applications of porous polymeric membranes. The structure development shows that an anisotropic porous morphology forms when an initial linear concentration gradient is applied to the model polymer solution.


Soft Matter ◽  
2018 ◽  
Vol 14 (29) ◽  
pp. 6043-6057 ◽  
Author(s):  
Shang Yik Reigh ◽  
Prabha Chuphal ◽  
Snigdha Thakur ◽  
Raymond Kapral

In the presence of a chemically active particle, a nearby chemically inert particle can respond to a concentration gradient and move by diffusiophoresis.


Lab on a Chip ◽  
2021 ◽  
Author(s):  
Yongtaek Im ◽  
Seunggyu Kim ◽  
Jinsoo Park ◽  
Hyung Jin Sung ◽  
Jessie Sungyun Jeon

An efficient and accurate antibiotic susceptibility test (AST) is indispensable for measuring the antimicrobial resistance of pathogenic bacteria. A minimal inhibitory concentration (MIC) can be obtained without performing repeated dilutions...


Lab on a Chip ◽  
2021 ◽  
Author(s):  
Bo Dai ◽  
Yan Long ◽  
Jiandong Wu ◽  
Shaoqi Huang ◽  
Yuan Zhao ◽  
...  

In the chemical and biological fields, creation of concentration gradient microenvironment is an important approach for many applications, such as crystal growth and drug screening. Although many concentration gradient generators...


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