Εξειδίκευση τύπου :	Άρθρο σε επιστημονικό περιοδικό
Τίτλος:	Hierarchical ‘rose-petal’ ZnO/Si surfaces with reversible wettability reaching complete water repellence without chemical modification
Δημιουργός/Συγγραφέας:	Kanidi, M. Bardakas, A. Kerasidou, A. Anastasopoulos, A. Tsamis, C. [EL] Κάνδυλα, Μαρία[EN] Kandyla, Maria
Ημερομηνία:	2023
Γλώσσα:	Αγγλικά
ISSN:	0947-8396 1432-0630
DOI:	10.1007/s00339-023-06529-w
Περίληψη:	Smart surfaces with externally controlled wettability patterns are ubiquitous building blocks for micro-/nanofluidic and lab-on-chip devices, among others. We develop hierarchical surfaces of ZnO nanorods grown on laser-microstructured silicon with reversible photo-induced and heat-induced wettability. The as-prepared surfaces are superhydrophilic, with very low water contact angles (~ 10°), and transition to a wetting state with high water contact angles (~ 150°) when annealed in vacuum. As the annealing temperature increases to 400 °C, the surfaces become completely water-repellent. Even though the annealed surfaces present high water contact angles, at the same time, they are very adhesive for water droplets, which do not roll off even when tilted at 90° or 180o (rose-petal effect), unlike standard hydrophobic surfaces which typically combine high water contact angles with low roll-off angles. The surfaces return to the superhydrophilic state when irradiated with UV light, which indicates a reversible wettability with external stimuli. Based on this transition, we demonstrate local modification of the wetting state of the surfaces by UV irradiation through a mask, which results in directed liquid motion, useful for microfluidic applications. The high contact angles obtained in this work are usually obtained only after chemical modification of the ZnO surface with organic coatings, which was not necessary for the hierarchical surfaces developed here, reducing the cost and processing steps of the fabrication route. These rose-petal surfaces can be used as “mechanical hands” in several applications, such as no-loss transport of small liquid volumes, precision coatings, spectroscopy, and others. Furthermore, the completely water-repellent surfaces, rarely reported elsewhere, may find important applications in frictionless liquid transport for microfluidic and other devices.
Τίτλος πηγής δημοσίευσης:	Applied Physics A
Τόμος/Κεφάλαιο:	129
Τεύχος:	5
Θεματική Κατηγορία:	[EL] Φυσική και θεωρητική χημεία[EN] Physical and theoretical chemistry
Λέξεις-Κλειδιά:	annealing hierarchical adhesive surfaces laser-microstructured silicon reversible wettability rose petal effect UV irradiation water repellence ZnO nanorods
EU Grant:	Advanced Materials and Devices
EU Grant identifier:	MIS 5002409
Κάτοχος πνευματικών δικαιωμάτων:	© 2023 The Author(s)
Ηλεκτρονική διεύθυνση στον εκδότη (link):	https://doi.org/10.1007/s00339-023-06529-w
Εμφανίζεται στις συλλογές:	Ινστιτούτο Θεωρητικής και Φυσικής Χημείας (ΙΘΦΧ) - Επιστημονικό έργο