Magnetic droplet actuation on natural (Colocasia leaf) and fluorinated silica nanoparticle superhydrophobic surfaces

Wetting of ferrofluids: Phenomena and control

“…This is obvious for example in magnetic droplet actuation, where droplet mobility depends on the surface wetting properties. Mats et al investigated magnetic actuation of aqueous droplets with micrometer-sized magnetic particles on three different surfaces: PTFE, superhydrophobic Colocasia leaf and glass slide coated with a commercial superhydrophobic spray solution [77]. The commercial spray proved to be best suited for magnetic actuation, while PTFE showed higher friction and the leaf was damaged by the magnetic microparticles.…”

Protein droplet actuation on superhydrophobic surfaces: a new approach toward anti-biofouling electrowetting systems

“…Roll-off angle measurement is a function of the gravitational force required to move a droplet when it is large enough to overcome the static friction force of the droplet on the solid surface. 35 BTNW is excluded from this particular study at this point in experimentation as the irreversibility of most of the solutions on this surface has discounted its potential as an EWOD actuating surface. The roll-off angle is measured on each surface under different conditions: immediately aer pipetting the droplet on the surface, aer a 765 s resting period, or aer application of a pre-conditioning voltage (either 150 V or 250 V) for either 75 seconds or 765 seconds.…”

“…buttery wings, colocasia leaves and lotus leaves). [35][36][37] Wang & Jiang 37 described ve possible states of superhydrophobic surfaces: Wenzel state, Cassie-Baxter state, Lotus state (special case of Cassie-Baxter state), transitional state between Wenzel and Cassie-Baxter states, and 'Gecko' state. In both Cassie-Baxter state and Lotus state, the superhydrophobic surfaces gain a self-cleaning property due to the high CA which reduces liquid droplet contact area with the surface and provides almost frictionless droplet movement.…”

“…All of the studies concerning superhydrophobic surfaces in EWOD devices require expensive equipment and/or involve complex processes that imply high ultimate production costs for large area, potentially disposable, bioassay devices. [38][39][40][41] Mats et al 35 investigated some aspects of the application of the commercial superhydrophobic material Ultra-Ever Dry® in a non-EWOD magnetic actuation based DMF device but only reported the roll-off angle required to move magnetic particle suspension droplets. The superhydrophobic surface was prepared by the simple spray-deposition process using a chromatography sprayer.…”

Magnetic digital microfluidics – a review

“…Finally, we discuss methods for improving the functionality of magnetic digital microfluidics to explore new research directions. On a magnetic digital microfluidic platform, liquid droplets are manipulated on a natural 52 or synthetic 13 hydrophobic surface. In the most conventional magnetic manipulation method, magnetic particles are added to the droplet to serve as the actuator ( Fig.…”