Recent progress in stimulus-responsive superhydrophobic surfaces

Li, Wen; Zhan, Yanlong; Amirfazli, Alidad; Siddiqui, Abdul Rahim; Yu, Sirong

doi:10.1016/j.porgcoat.2022.106877

Cited by 26 publications

(16 citation statements)

References 212 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The contact angle of asgrown ZnO nanorods on flat silicon is very low (~ 10°), indicating super-hydrophilicity. This observation is attributed to hydroxy groups that are created on the surface of ZnO nanorods during synthesis [3]. Indeed, it is established that the wettability of metal oxides in general switches between hydrophilicity and hydrophobicity, depending on the presence of hydroxy groups on their surface [45].…”

Section: Resultsmentioning

confidence: 99%

“…Upon UV irradiation, electron-hole pairs are formed in the lattice of ZnO. Some of the holes form surface oxygen vacancies, while the electrons form defect sites, which are kinetically more favorable for hydroxy adsorption than oxygen adsorption, enhancing the surface hydrophilicity [3]. To reverse the photo-induced effect, it has been demonstrated that oxygen atoms gradually replace the hydroxy groups adsorbed on the defect sites, resulting in surface hydrophobicity, when a sample is placed in the dark or annealed in vacuum after UV irradiation [23,46,47].…”

Section: Resultsmentioning

confidence: 99%

“…Furthermore, a surface with reversible wettability, switching between hydrophilicity and hydrophobicity, is required for rapid water motion, microfluidic devices, smart membranes, sensors, etc. [3]. A wettability switch can be triggered by various external stimuli, including electricity (based on electrowetting or the doping of conducting polymers) [4], temperature (based on thermoresponsive polymers) [5,6], light (based on photosensitive metal-oxide semiconductors and photo-responsive organic compounds) [7], pH (based on protonation and deprotonation of pH-responsive surfaces) [8,9], mechanical strain (based on extending and unloading elastic films) [10,11], etc.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Hierarchical ‘rose-petal’ ZnO/Si surfaces with reversible wettability reaching complete water repellence without chemical modification

et al. 2023

View full text Add to dashboard Cite

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.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Hierarchical ‘rose-petal’ ZnO/Si surfaces with reversible wettability reaching complete water repellence without chemical modification

et al. 2023

View full text Add to dashboard Cite

show abstract

“…The high adhesive surface can capture droplet, and move the high adhesive surface to the target position and turn the surface into low adhesive surface. At the same time, the droplet fell on the destination [49,61] . However, the process of capturing and releasing is too complex and the surfaces with responsive chemical compositions or tunable microstructure are often needed.…”

Section: Resultsmentioning

confidence: 99%

Self‐Transportation of Superparamagnetic Droplets on a Magnetic Gradient Slippery Surface with On/Off Sliding Controllability

Lai

Liu

et al. 2022

ChemPhysChem

View full text Add to dashboard Cite

Recently, research about droplet self‐transportation on slippery surfaces has become a hotspot. However, to achieve on/off sliding control during the self‐transportation process is still difficult. Herein, we report a magnetic slippery surface, and demonstrate on/off sliding control during the self‐transportation of superparamagnetic droplets. The surface is prepared through integrating a substrate that has a gradient magnetic region with a layer of paraffin infused hydrophobic SiO2 nanoparticles. On the surface, a superparamagnetic droplet is pinned at room temperature (about 25 °C), while it can self‐transport directionally as the temperature is increased to about 70 °C. When the temperature is cooled down again, the droplet would return to the pinned state, indicating that on/off sliding control during the self‐transportation process can be achieved. Furthermore, based on the excellent controllability, controllable coalescence of two droplets from opposite direction is displayed, demonstrating its potential application in numerous areas.

show abstract

“…Therefore, it is straightforward that significant contributions have been centered on the development of surface treatment techniques and overlayers which combines passive anti-icing and active deicing together to respond for the above challenges. Consequently, a number of stimulus-responsive SHSs have been created to deal with various harsh environments, such as electrothermal, photothermal, or magnetothermal coatings in combination with superhydrophobicity. − Wang et al synthesized a type of solid organogel material with a regenerable sacrificial alkane surface layer, enabling long time icing delay and thermal deicing properties . Ma et al reported an ice-phobic surface with integrated spectral selectivity and superhydrophobicity resulting from spin-coating TiN nanoparticles on etched aluminum alloy plates; the solar-thermal conversion of the surface empowers anti-icing of a sessile droplet at −60 °C under 1-sun illumination .…”

Section: Introductionmentioning

confidence: 99%

Spray-Coated Superhydrophobic Overlayer with Photothermal and Electrothermal Functionalities for All-Weather De/anti-icing Applications

Zan

Tao

et al. 2022

Langmuir

View full text Add to dashboard Cite

High-performance de/anti-icing overlayers which can be deposited on diverse surfaces offer great potential in many industrial settings and daily life, yet a versatile overlayer applicable to all-weather conditions (high humidity, low temperature, raining, snowing, etc.) is in high demand for practical applications. This study presents the fabrication and application of a superhydrophobic overlayer with a bioinspired hierarchical surface which additionally possesses photothermal and electrothermal functionalities, so it can operate as a de/anti-icing layer in extreme environments. The overlayer, with a papilla-like microstructure similar to that of a lotus leaf, features polydopamine-decorated layered basic zinc acetate microparticles distributed in the framework of multiwalled carbon nanotubes. Specifically, the overlayer is superhydrophobic, and its capability of suppressing the condensation of water droplets and growth of ice crystals is verified by both in situ environmental scanning electron microscopy observations and freezing experiments. Moreover, the overlayer can be warmed up to 74 and 105 °C under the excitation of sunlight and direct current bias, respectively, which is sufficiently high for deicing in severe weather. It is worth mentioning that the overlayer is produced by a spray-coating technique; therefore, it is suitable for large-scale deployment on arbitrary substrate materials. The findings provide insights into a new strategy for engineering multifunctional overlayers and can lead to expanding applications of composite coatings.

show abstract

Recent progress in stimulus-responsive superhydrophobic surfaces

Cited by 26 publications

References 212 publications

Hierarchical ‘rose-petal’ ZnO/Si surfaces with reversible wettability reaching complete water repellence without chemical modification

Hierarchical ‘rose-petal’ ZnO/Si surfaces with reversible wettability reaching complete water repellence without chemical modification

Self‐Transportation of Superparamagnetic Droplets on a Magnetic Gradient Slippery Surface with On/Off Sliding Controllability

Spray-Coated Superhydrophobic Overlayer with Photothermal and Electrothermal Functionalities for All-Weather De/anti-icing Applications

Contact Info

Product

Resources

About