Abstract
In magnetowetting, the material properties of liquid, surface morphology of solid, and applied external field are three major factors used to determine the wettability of a liquid droplet on a surface. For wetting measurements, an irregular or uneven surface could result in a significant experimental uncertainty. The periodic array with a hexagonal symmetry structure is an advantage of the anodic aluminum oxide (AAO) structure. This study presents the results of the wetting properties of magnetic nanofluid sessile droplets on surfaces of various AAO pore sizes under an applied external magnetic field. Stable, water-based magnetite nanofluids are prepared by combining the chemical co-precipitation with the sol-gel technique, and AAO surfaces are then generated by anodizing the aluminum sheet in the beginning. The influence of pore size and magnetic field gradient on the magnetowetting of magnetic nanofluids on AAO surfaces is then investigated by an optical test system. Experimental results show that increasing the processing voltage of AAO templates could result in enhanced non-wettability behavior; that is, the increase in AAO pore size could lead to the increase in contact angle. The contact angle could be reduced by the applied magnetic field gradient. In general, the magnetic field has a more significant effect at smaller AAO pore sizes.
Highlights
Due to the wide potential applications of superhydrophobic and superhydrophilic surfaces, such as self-cleaning [1], anti-icing [2], spray cooling [3], and energy harvesting [4], surface wetting control has been an important issue
There was no study evaluating the magnetowetting of magnetic nanofluids on anodic aluminum oxide (AAO) surfaces
The purpose of this study is to investigate experimentally the wetting properties of magnetic nanofluid sessile droplets on surfaces of various AAO pore sizes under an applied external magnetic field
Summary
Due to the wide potential applications of superhydrophobic and superhydrophilic surfaces, such as self-cleaning [1], anti-icing [2], spray cooling [3], and energy harvesting [4], surface wetting control has been an important issue. Through the increase of solid surface roughness, resulting in an incremental existence of air in the interface between the liquid droplet and solid surface, a contact angle can be changed from hydrophilic to hydrophobic [19,20,21,22]. Ran et al [27] published a study on the wetting of water droplets on porous alumina surface Their experiments showed that the wetting phenomenon could change from the Wenzel state to the Cassie state via increasing the pore diameter, which causes a contact angle of 132◦ at 420 nm pore diameter. Such a phenomenon of increase in contact angle was indicated in Kim et al [28]
Sign-in/Register to view highlights & summary 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.
