Abstract
We introduce multi-gradients including Laplace pressure gradient, wettable gradient and wettable different gradient on a high adhesion surface via special wedge-pattern and improved anodic oxidation method. As a result of the cooperative effect mentioned above, controlled directional motion of a droplet on a high adhesion surface is realized, even when the surface is turned upside down. The droplet motion can be predicted and the movement distances can be controlled by simply adjusting the wedge angle and droplet volume. More interestingly, when Laplace pressure gradient is introduced on a V-shaped wettable gradient surface, two droplets can move toward one another as designed.
Highlights
Directions on the high adhesion surface, which is significant for designing smart materials that can be extended to the realm of controlling fluidic transport in directions, pharmaceutical detection, microfluidic tools and so on
In order to realize the controlled self-propelling of droplet on a high adhesion surface, we combine wettable gradient and Laplace pressure simultaneously on a surface
Graphite plates were prepared by gradient anodic oxidation to form wettable gradient via the change in the surface chemical composition, as our previous report[21]
Summary
Liquid transport on wedge-pattern surfaces was first studied by Khoo and Tseng. They presented liquid transport on nanotextured surface with wedge-shaped track[27]. The movement behaviour of water droplet of 5 μL on the wettable gradient surfaces (9.0°/mm) with different wedge angles is shown in Figs 2a and S6. We realize the self-propelling of droplets on a high adhesion surface via the collaborative effect of Laplace pressure and wettable gradient and the movement distance can be adjusted by the angle of wedge-patterns. Apart from the single droplet motion, we fabricated a surface with V-shape wettable gradient and Laplace pressure to realize the controlled motion of two droplets on the basis of the aforementioned method. The movement distance can be controlled via adjusting the angle of the wedge-pattern On this basis, more interesting shape pattern could be designed to manipulate individual droplet or multiple droplets, which has great potential application prospect in pharmaceutical detection and microfluidic tools[32,33,34]
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
