Friction and Wetting Transitions of Magnetic Droplets on Micropillared Superhydrophobic Surfaces.
نویسندگان
چکیده
Reliable characterization of wetting properties is essential for the development and optimization of superhydrophobic surfaces. Here, the dynamics of superhydrophobicity is studied including droplet friction and wetting transitions by using droplet oscillations on micropillared surfaces. Analyzing droplet oscillations by high-speed camera makes it possible to obtain energy dissipation parameters such as contact angle hysteresis force and viscous damping coefficients, which indicate pinning and viscous losses, respectively. It is shown that the dissipative forces increase with increasing solid fraction and magnetic force. For 10 µm diameter pillars, the solid fraction range within which droplet oscillations are possible is between 0.97% and 2.18%. Beyond the upper limit, the oscillations become heavily damped due to high friction force. Below the lower limit, the droplet is no longer supported by the pillar tops and undergoes a Cassie-Wenzel transition. This transition is found to occur at lower pressure for a moving droplet than for a static droplet. The findings can help to optimize micropillared surfaces for low-friction droplet transport.
منابع مشابه
Electrical actuation-induced droplet transport on smooth and superhydrophobic surfaces
Electrical control of liquid droplet motion and wettability has wide-ranging applications in the field of MEMS, lab-on-a-chip devices and surface engineering, in view of the resulting enhanced flow control opportunities, low power consumption and the absence of mechanical moving parts. This article summarizes recent progress towards understanding of the fundamentals underlying electrical actuat...
متن کاملWettability Switching Techniques on Superhydrophobic Surfaces
The wetting properties of superhydrophobic surfaces have generated worldwide research interest. A water drop on these surfaces forms a nearly perfect spherical pearl. Superhydrophobic materials hold considerable promise for potential applications ranging from self cleaning surfaces, completely water impermeable textiles to low cost energy displacement of liquids in lab-on-chip devices. However,...
متن کاملEffect of droplet morphology on growth dynamics and heat transfer during condensation on superhydrophobic nanostructured surfaces.
Condensation on superhydrophobic nanostructured surfaces offers new opportunities for enhanced energy conversion, efficient water harvesting, and high performance thermal management. These surfaces are designed to be Cassie stable and favor the formation of suspended droplets on top of the nanostructures as compared to partially wetting droplets which locally wet the base of the nanostructures....
متن کاملNanostructures in superhydrophobic Ti6Al4V hierarchical surfaces control wetting state transitions.
This paper mainly reports the wetting state of liquid droplets on a Ti6Al4V micro-nanoscale hierarchical structured hydrophobic surface. In this work, the detailed action mechanism of the secondary nanostructure in the hierarchical structure on the wetting-state transition (from the Wenzel state to the Cassie state) was revealed and discussed. The variation of micro-morphology of the sample sur...
متن کاملFrom Initial Nucleation to Cassie-Baxter State of Condensed Droplets on Nanotextured Superhydrophobic Surfaces
Understanding how droplet condensation happens plays an essential role for our fundamental insights of wetting behaviors in nature and numerous applications. Since there is a lack of study of the initial formation and growing processes of condensed droplets down to nano-/submicroscale, relevant underlying mechanisms remain to be explored. We report an in situ observation of vapor condensation o...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Small
دوره 13 38 شماره
صفحات -
تاریخ انتشار 2017