Sliding and Rolling Motion of a Ferro-Liquid Droplet on the Hydrophobic Surface under Magnetic Influence

Yilbaş, Bekir Sami; Abubakar, Abba Abdulhamid; Hassan, Ghassan; Al‐Qahtani, Hussain; Al‐Sharafi, Abdullah; Kassas, Mahmoud; Alzahran, Abdullah A; Mohammed, Anwaruddin Siddiqui

doi:10.1021/acs.langmuir.2c00255

Cited by 5 publications

(9 citation statements)

References 38 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…the droplet position for a specific volume, as seen in Figure . Moreover, k also changes with droplet volume in a similar magnetic environment, contrasting the existing reports . Interestingly, for a particular drop volume, k is constant until s = 6 mm, as shown in Figure .…”

Section: Resultscontrasting

confidence: 68%

“…Moreover, k also changes with droplet volume in a similar magnetic environment, contrasting the existing reports. 31 Interestingly, for a particular drop volume, k is constant until s = 6 mm, as shown in Figure 11. As the droplet crosses the threshold distance of s = 6 mm, a step increment (marked by the dashed line) is observed for the shape factor k for all the droplet volumes.…”

Section: ■ Results and Discussionmentioning

confidence: 90%

“…Additionally, n -hexadecane is less viscous than other commonly used hydrocarbon oils in ferrofluids, such as silicone oil and oleic acid, thereby ensuring lesser viscous resistance and smooth transport of the droplet along the wire. The magnetic liquid solution is synthesized in-house using ultrasonic disruption technique as reported in the literature, , briefly mentioned in the following texts. In the first step, the iron (II, III) oxide nanopowder of size 50–100 nm is dispersed in the base fluid at a concentration of 3.15% by weight (0.50% by volume) and later subjected to mechanical stirring using a vortex shaker (Make: Spinix, Tarsons).…”

Section: Methodsmentioning

confidence: 99%

“…In contrast, magnetic field-mediated droplet transportation on a wire can be a promising avenue that offers contactless actuation in addition to the aforementioned benefits. The capabilities of active magnetic propulsion have already been highlighted in numerous research works atop flat surfaces − or microchannels . Unfortunately, studies elucidating droplet propulsion on a wire using a magnetic field are rare.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Magnetic-Field Mediated Active Propulsion of Ferrofluid Droplets on a Wire

2023

View full text Add to dashboard Cite

Droplet actuation on wires or fibers is highly relevant to digital microfluidics applications. Several different passive or active actuation mechanisms have been studied, including capillary pressure, thermal gradient, tilting, acoustics, and electrowetting, to name a few. However, the lack of precise control and accurate droplet positioning during its actuation on a wire limits the use of earlier methods. On the other hand, using a nonuniform magnetic field to actuate a droplet on a micrometer-size wire helps overcome the above limitations. In this context, we elucidate the motion of microliter-size ferrofluid droplets, smaller than the capillary length, in the presence of a permanent magnet using a simple yet robust experimental setup, wherein the clamshell shape droplets hang on a wire at a predetermined distance from the magnet. Beyond a critical volume, the droplet starts moving toward the magnet while exhibiting shape evolution continuously. Using a high-speed videography technique, we uncover the intricate relationship between the magnetowetting, favoring continuous shape evolution of droplets of different sizes, and their actuation dynamics (velocity) on a wire, which has scarcely been explored. The most significant contribution of this study is the detailed evaluation of the shape factor (k), relating the shape evolution of the droplet to its velocity through the contact angle hysteresis force. A theoretical framework has also been proposed, comprising different forces in action, which is found to set forth a good match with the experimental results. The results from this study are expected to open up new avenues in digital microfluidics, specifically in drug delivery, ferrobotics, and droplet logic gates, to name a few.

show abstract

Section: Resultscontrasting

confidence: 68%

Section: ■ Results and Discussionmentioning

confidence: 90%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Magnetic-Field Mediated Active Propulsion of Ferrofluid Droplets on a Wire

2023

View full text Add to dashboard Cite

show abstract

“…[8,15] However, in most research related to the development of these robots, their applicability is only demonstrated using magnets controlled by hand [8][9][10][11][12] or, in some cases, through mechanical stages. [13,16] Moreover, some studies that explore the locomotion of these robots in 3D environments rely solely on manually controlled magnets. [17,18] Electromagnets are essential for precisely controlling the locomotion of droplet robots.…”

Section: Introductionmentioning

confidence: 99%

Multimodal Locomotion of Magnetic Droplet Robots Using Orthogonal Pairs of Coils

Ramos-Sebastian

Lee

Kim

2023

Advanced Intelligent Systems

View full text Add to dashboard Cite

Recently, several fluidlike, shape‐adaptable magnetic microrobots have been developed to overcome the drawbacks posed by the rigid structure of traditional magnetic microrobots. However, most of their control systems rely on permanent magnet‐based systems, which are unfeasible for large‐scale environments, such as in vivo applications. Herein, an electromagnetic system comprising orthogonal pairs of coils is used to generate global magnetic fields, that is, magnetic fields that are applied equally to large volumes, for the multimodal locomotion of ferrofluidic robots composed of magnetic micro‐/nanoparticles. Three main magnetic field configurations, with their respective locomotion mechanisms, are explored: uniform rotating fields for droplet fission–fusion motions and locomotion; magnetic trapping point‐based locomotion for single‐ and collective‐droplet manipulation; and field‐free region‐based dragging locomotion and selective droplet control. The effectiveness of the proposed multimodal locomotion mechanisms and potential applications are experimentally demonstrated in minichannels through selective mixing, targeted delivery, and optimized magnetic heating applications. These locomotion mechanisms using global fields enable the use of fluidlike magnetic microrobots in large‐volume applications.

show abstract

Directional Manipulation of Drops and Solids on a Magneto-Responsive Slippery Surface

Banerjee,

Gunjan,

Mitra

2024

Langmuir

View full text Add to dashboard Cite

The cloaking of the droplet and solid spheres by a thin ferrofluid layer forms a ferrofluid-wetting ridge, enabling the magnet-assisted directional manipulation of droplets and solid spheres on the magneto-responsive slippery surface. Understanding the interplay of various forces governing motion unravels the manipulation mechanism. The transportation characteristics of droplets and solid spheres on such surfaces enable their controlled manipulation in multiple applications. Here, we prepare magnetoresponsive slippery surfaces by using superhydrophobic coatings on glass slides, creating a porous network and impregnating them with ferrofluid. Using a permanent magnet (and its translation) in the proximity of these surfaces, we manipulate the motion of liquid drops and solid spheres. Upon dispensing the droplet on the magneto-responsive slippery surface, the droplet is cloaked by a thin ferrofluid layer and forms a ferrofluid wetting ridge. Incorporating the magnetic field creates a magnetic-nanoparticle-rich zone surrounding the ferrofluid ridge. Thereafter, the motion of the magnet gives rise to the movement of the droplet. We found that the interplay of the magnetic force and viscous drag leads to the magnetic manipulation of droplets in a controlled fashion up to a certain magnet speed. Increasing the magnet speed further results in the uncontrolled motion of the droplet, where the droplet cannot follow the magnet trajectory. Moreover, we delineate multifunctional droplet manipulations, such as trapping, pendant droplet manipulation, coalescence, and microchemical reactions, which have wide engineering applications.

show abstract

Sliding and Rolling Motion of a Ferro-Liquid Droplet on the Hydrophobic Surface under Magnetic Influence

Cited by 5 publications

References 38 publications

Magnetic-Field Mediated Active Propulsion of Ferrofluid Droplets on a Wire

Magnetic-Field Mediated Active Propulsion of Ferrofluid Droplets on a Wire

Multimodal Locomotion of Magnetic Droplet Robots Using Orthogonal Pairs of Coils

Directional Manipulation of Drops and Solids on a Magneto-Responsive Slippery Surface

Contact Info

Product

Resources

About