Omnidirectional transport and navigation of Janus particles through a nematic liquid crystal film

Sahu, Dinesh Kumar; J., Kole, S.; Ramaswamy, Sriraṁ; Dhara, Surajit

doi:10.1103/physrevresearch.2.032009

Cited by 23 publications

(25 citation statements)

References 37 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Hernàndez-Navarro et al [13] reported on reconfigurable swarms of asymmetric pear-shaped colloids driven by LCEP and steered by photoactivated photo-switchable surface anchoring. Sahu, Ramaswamy, and Dhara [24] reported on an in-plane omnidirectional transport of metal-dielectric Janus spheres that is based on the asymmetries of both the particles and the surrounding director field; the direction of propulsion is controlled by varying the field frequency and amplitude [24]. In the described DI-LCEP effect, the particle is also steered in the plane of the cell by changing the frequency and voltage of the AC electric field, but the difference is that the particle is a symmetric homogeneous sphere.…”

Section: Discussionmentioning

confidence: 99%

Soliton-induced liquid crystal enabled electrophoresis

Xiao

Shiyanovskii

et al. 2020

Phys. Rev. Research

View full text Add to dashboard Cite

Manipulation of particles by a uniform electric field, known as electrophoresis, is used in a wide array of applications. Of especial interest is electrophoresis driven by an alternating current (AC) as it eliminates electrode blocking and produces a steady motion. The known mechanisms of AC electrophoresis require that either the particle or the surrounding medium are asymmetric. This asymmetry is usually assured before the field is applied, as in the case of Janus spheres. We report on a new mechanism of AC electrophoresis, in which the symmetry is broken only when the field exceeds some threshold. The new mechanism is rooted in the nature of electrophoretic medium, which is an orientationally ordered nematic liquid crystal. Below the threshold, the director field of molecular orientation around a spherical particle is of a quadrupolar symmetry. Above the threshold, the director forms a polar self-confined perturbation around the inclusion that oscillates with the frequency of the applied field and propels the sphere. The director perturbations are topologically trivial and represent particlelike solitary waves, called "director bullets" or "directrons". The direction of electrophoretic transport can be controlled by the frequency of the field. The AC directron-induced liquid crystal enabled electrophoresis can be used to transport microscopic cargo when other modes of electrophoresis such as induced charge electrophoresis are forbidden.

show abstract

Section: Discussionmentioning

confidence: 99%

Soliton-induced liquid crystal enabled electrophoresis

Xiao

Shiyanovskii

et al. 2020

Phys. Rev. Research

View full text Add to dashboard Cite

show abstract

“…Further, we make two observations in comparison to previous studies on quadrupolar Janus particles. 37,39 Firstly, the threshold field required for Janus particles with hyperbolic hedgehog defects ( E = 1.2 V μm −1 ) is almost comparable to that of particles with Saturn ring defects ( E = 1.3 V μm −1 ). But it is relatively lower compared to particles with boojum defects ( E = 2.1 V μm −1 ).…”

Section: Resultsmentioning

confidence: 87%

“…In particular, the direction of motion of quadrupolar particles depends on the orientation of the metal hemisphere with respect to the director n̂ . 37,39…”

Section: Resultsmentioning

confidence: 99%

“…For Janus quadrupolar particles, the surrounding medium (director profile) is symmetric and the asymmetric particle breaks the fore-aft symmetry of electroosmotic flows. 37,38 In the case of Janus dipolar particles, both the medium and the particles are asymmetric and they both are responsible for breaking the symmetry of the flow. Overall, the Janus dipolar particles display superior electrophoresis as far as propulsion is concerned, compared to both Janus and non-Janus quadrupolar particles in nematic liquid crystals.…”

Section: Discussionmentioning

confidence: 99%

“…Very recently, we have shown that metal-dielectric Janus particles with a quadrupolar director structure can be transported and the direction of motion can be controlled by changing the amplitude and frequency of the applied field. 37–39…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations