Magnetic Nanomotors in Emulsions for Locomotion of Microdroplets

Abstract

The locomotion of droplets in emulsions is of practical significance for fields related to medicine and chemical engineering, which can be done with a magnetic field to move droplets containing magnetic materials. Here, we demonstrate a new method of droplet locomotion in the oil-in-water emulsion with the help of a nonuniform magnetic field in the case where magnetic nanoparticles (MNPs) are dispersed in the continuous phase of the emulsion. The paper analyses the motion of the droplets in a liquid film and in a capillary for various diameters of droplets, their number density, and viscosity of the continuous phase of the emulsion. It is established that the mechanism of droplet locomotion in the emulsion largely depends on the wettability of MNPs. Hydrophobic nanoparticles are adsorbed on the droplet surfaces, forming the agglomerates of MNPs with the droplets. Such agglomerates move at much higher velocities than passive droplets. Hydrophilic nanoparticles are not adsorbed at the surfaces of the droplets but form mobile magnetic clusters dispersed in the continuous phase of the emulsion. Mobile magnetic clusters set the surrounding liquid and droplets in motion. The results obtained in this paper can be used in drug delivery.

pH/magnetic dual responsive Pickering emulsion stabilized by Fe3O4@SiO2@chitosan nanoparticles

“…6), the emulsifier particles peel away from the oil–water interface and become concentrated on the inner wall of the vial bottle to demulsification. 42 This will also facilitate the separation of emulsifiers for reuse. In terms of the molecular weights of chitosan, some Fe 3 O 4 @SiO 2 @CS-2.5 kDa O/W droplets are distributed piecemeal despite most of the emulsion being broken.…”

On Nanomachines and Their Future Perspectives in Biomedicine

“…An alternative approach has been employed for transportation and delivery of microdroplets. [ 87 ] Carbon‐coated iron motors were modified to display either a hydrophobic or hydrophilic surface. When hydrophobic surfaces were considered, the motors were attached to the microdroplets by van der Waals interactions and moved the droplets under the actuation of a magnetic field gradient.…”

3D Active Brownian Motion of Single Dust Particles Induced by a Laser in a DC Glow Discharge

“…Self-consistent motion of active particles is usually called active motion. Examples of active particles include some bacteria, mobile cells [ 5 , 6 , 7 ], micro- and nanorobots [ 8 ], active microcatalysts [ 9 , 10 , 11 ], microdroplets in an emulsion [ 12 , 13 ], dust particles in discharge plasma and superfluid helium [ 14 , 15 , 16 , 17 , 18 ] etc. Active particles can either move independently or demonstrate a collective nature [ 5 , 19 ].…”

“…The mean kinetic energy of active particles can significantly exceed the mean kinetic energy (temperature) of the environment, which indicates a significant nonequilibrium of the process [ 3 ]. The main mechanisms of activity of microparticles are: chemical reactions [ 9 , 10 , 11 ], Marangoni effect [ 12 ], quantum effects [ 18 ], ion drag forces and photophoretic forces in colloidal plasma [ 14 , 15 , 16 , 17 ], external electromagnetic fields [ 13 ], etc.…”