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Dynamics of Electrically Modulated Colloidal Droplet Transport
- Source :
- Langmuir. 31:11269-11278
- Publication Year :
- 2015
- Publisher :
- American Chemical Society (ACS), 2015.
-
Abstract
- Electrically actuated transport dynamics of colloidal droplets, on a hydrophobic dielectric film covering an array of electrodes, is studied here. Specifically, the effects of the size and electrical properties (zeta-potential) of the colloidal particles on such transport characteristics are investigated. For the colloidal droplets, the application of an electrical voltage leads to additional attenuation of the local dielectric-droplet interfacial tension. This is due to the electrically triggered enhanced colloidal particle adsorption at the dielectric-droplet interface, in the immediate vicinity of the droplet three-phase contact line (TPCL). The extent of such interfacial particle adsorption, and hence, the extent of the consequential reduction in the interfacial tension, is dictated by the combined effects of the three-phase contact line spreading, particle size, the interfacial electrostatic interaction between the colloidal particles (if charged) and the charged dielectric surface above the activated electrode, and the interparticle electrostatic repulsion. The electrical driving force of varying magnitude, stemming from this altered solid-liquid interfacial tension gradient in the presence of the colloidal particles, culminates in different droplet transport velocity and droplet transfer frequency for different colloidal droplets. We substantiate the inferences from our experimental results by a quasi-steady state force balance model for colloidal droplet transport. We believe that the present work will provide an accurate framework for determining the optimal design and operational parameters for digital microfluidic chips handling colloidal droplets, as encountered in a plethora of applications.
- Subjects :
- endocrine system
Work (thermodynamics)
Materials science
digestive, oral, and skin physiology
Microfluidics
technology, industry, and agriculture
Nanotechnology
Surfaces and Interfaces
Dielectric
Condensed Matter Physics
Electrostatics
complex mixtures
eye diseases
Physics::Fluid Dynamics
Condensed Matter::Soft Condensed Matter
Surface tension
Colloid
Chemical physics
Electrode
Electrochemistry
General Materials Science
Particle size
Spectroscopy
Subjects
Details
- ISSN :
- 15205827 and 07437463
- Volume :
- 31
- Database :
- OpenAIRE
- Journal :
- Langmuir
- Accession number :
- edsair.doi.dedup.....b89820ee9f9bc7d698a8fc69fd04bb87