Examination of contact angles of magnetic fluid droplets on different surfaces in uniform magnetic field

Magnetowetting dynamics of sessile ferrofluid droplets: a review

“…113,114 Lee et al 100 argued that a decrease in the g ls further directed the contactangle dynamics to lower values. As such, the contact angle of the elongated drop was found to decrease initially up to a field strength of 150 G, beyond which it started to increase, which was similar to the observations of Guba et al 106 Beyond H 4 150 G, the contact-angle dynamics were dominated by shape deformation, despite the continuous reduction of g ls at higher field strengths. The aspect ratio of the droplet had a greater slope after H 4 150 G, and as such the contact angle tends to be higher at a higher aspect ratio.…”

“…Ferrofluid droplets, when exposed to a uniform magnetic field, elongate in the direction of the applied field. 50,82,[97][98][99][100][101][102][103][104][105][106][107][108][109] Earlier, we mentioned that the magnetic normal traction pushes the interface in the direction of the field, resulting in elongation. At the same, time the contact angle decreases considerably.…”

“…112 The most recent studies have further established that the magnetic nanoparticle concentration and the substrate wettability greatly affect the shape-change and contact-angle dynamics in a uniform magnetic field. [105][106][107] Guba et al 106 reported the differences in the contact-line behavior of water-based FF droplets during their elongation on a series of hydrophilic and hydrophobic substrates. On a hydrophilic silicon wafer surface, the contact line remained nearly pinned during the elongation of the droplet, resulting in a higher degree of contact angle drop.…”

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

“…The wetting dynamics of the droplet can be further modified as the hydrophobic wetting state of the surface changes such that the droplet undergoes large deformations and achieves pointy shapes with sharp tips on less wettable surfaces as the magnetic source is located above the droplet surface . The ferro-particle influences the droplet pinning on the hydrophobic surface; hence, as the concentration increases, the magnetic influence created by the external field enhances the pinning while ceasing the droplet motion. Hence, exploring the ferro-liquid droplet behavior on a hydrophobic surface subjected to an external magnetic influence becomes essential.…”

Lateral and Axisymmetric Ferrofluid Oscillations in a Cylindrical Tank in Microgravity

“…The most remarkable feature of these predictions is, however, the excellent agreement with experimental results observed for the lateral frequencies. While the interpolation of Γ and 𝜃 𝑐 results in an adjusted coefficient of determination * However, previous works [60][61][62] have reported a dependence between the apparent contact angle and the applied magnetic field of ferrofluid droplets, an effect that should be explored with larger datasets for the setup employed in this work. 𝑅 2 adj = 0.983 (with 3 explanatory variables, Γ, 𝜃 𝑐 , and 𝐼) and a mean-squared error of 𝑀𝑆𝐸 = 0.01 rad/s, the use of averaged values returns 𝑅 2 adj = 0.976 with a single explanatory variable 𝐼 and an 𝑀𝑆𝐸 = 0.02 rad/s.…”