English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Zendy Plus

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Zendy Tools

Zendy Open

Graphitic micro-particles coated with thin layers in solution aretechnologically interesting as they can be manipulated with electric fields.Modeling the electrical manipulation of submerged layered micro-particlesanalytically or numerically is not straight forward. In particular, thegeneration of reliable quantitative torque predictions for electro-orientationexperiments has been elusive. The traditional Laplace model approximates thecoated particle by an ellipsoid with a confocal ellipsoidal layer and solvesLaplace's equation to produce convenient analytical predictions. However, dueto the non-uniformity of the layer thickness around the ellipsoid, this methodcan lead to incorrect torque predictions. Here we present a new theoreticaldual-ellipsoid Laplace model that corrects the effect of the non-uniform layerthickness by calculating two layered ellipsoids, each accounting for thecorrect layer thickness along each relevant direction for the torque. Our modeldescribes the electro-orientation of submerged lipid-coated graphiticmicro-particles in the presence of an alternating current (AC) electric fieldand is valid for ellipsoids with moderate aspect ratios and coated with thinshells. It is one of the first models to generate correct quantitative electrictorque predictions. We present model results for the torque versus frequencyand compare them to our measurements for lipid-coated highly ordered pyrolyticgraphite (HOPG) micro-flakes in aqueous NaCl solution at MHz frequencies. Theresults show how the lipid shell changes the overall electrical properties ofthe micro-flakes so that the torque is low at low frequencies and increases athigher frequencies into the MHz regime. The torque depends critically on thelipid-shell thickness, the solution conductivity and the shape of the particle,all of which can be used as handles to control the response of the particles.

colloids and surfaces a physicochemical and engineering aspects

Orienting lipid-coated graphitic micro-particles in solution using AC  electric fields: A new theoretical dual-ellipsoid Laplace model for  electro-orientation