Hassan Ghassan, Yilbas Bekir Sami, Abubakar Abba Abdulhamid, Al-Qahtani Hussain, Al-Sharafi Abdullah
Mechanical Engineering Department, King Fahd University of Petroleum and Minerals (KFUPM) Dhahran 31261 Saudi Arabia
K. A. CARE Energy Research & Innovation Center Dhahran 31261 Saudi Arabia.
RSC Adv. 2023 Nov 29;13(49):34866-34875. doi: 10.1039/d3ra06073j. eCollection 2023 Nov 22.
Dynamically manipulating droplet motion on hydrophobic surfaces is crucial in various fields, including biomedical, sensing, actuation, and oil-water separation applications. Ferrofluid droplets can be manipulated and controlled using external magnetic forces. The creation of ferrofluids involves multiple procedures that can affect the functionality and stability of droplet manipulation, limiting their use in sustainable applications. This study investigates the dynamics of droplet motion over functionalized and non-functionalized ferroparticles, considering different droplet volumes, ferroparticle layer widths, and wt% concentrations. The translational and sliding velocities of the droplets are measured using high-speed camera recording with a tracker application. The finding revealed the transformation of a droplet sliding motion into a rolling motion with propulsion under the magnetic influence. The sliding velocity increases for the droplets moving over the ordinary ferroparticles on the hydrophobic surface. However, the droplet motion is dominated by rolling in the case of hydrophobic ferro particles. The droplet sliding velocity rises sharply at high concentrations (or layer width) of ferroparticle as the magnetic bond number rises sharply to 3. A newborn droplet adheres to the magnet surface during droplet rolling and sliding motion.
在包括生物医学、传感、驱动和油水分离应用等各个领域，动态操纵疏水表面上的液滴运动至关重要。铁磁流体液滴可以利用外部磁力进行操纵和控制。铁磁流体的制备涉及多个过程，这些过程会影响液滴操纵的功能和稳定性，限制了它们在可持续应用中的使用。本研究考虑了不同的液滴体积、铁磁颗粒层宽度和重量百分比浓度，研究了功能化和非功能化铁磁颗粒上液滴运动的动力学。使用带有跟踪应用程序的高速摄像机记录来测量液滴的平移速度和滑动速度。研究结果揭示了在磁场影响下，液滴的滑动运动会转变为带有推进力的滚动运动。在疏水表面上，液滴在普通铁磁颗粒上移动时，滑动速度会增加。然而，在疏水铁磁颗粒的情况下，液滴运动以滚动为主。随着磁键数急剧上升至3，在铁磁颗粒高浓度（或层宽度）时，液滴滑动速度急剧上升。在液滴滚动和滑动运动过程中，新生液滴会附着在磁体表面。
