Superhydrophobic Surfaces Enabled by Femtosecond Fiber Laser-Written Nanostructures

Inspired by the self-cleaning and water-repellent lotus leaf, we have developed an efficient process to create superhydrophobic metal surfaces using a femtosecond fiber laser and have investigated the mechanisms of the structured metal surfaces in relation to their hydrophobicity. The at will feature of femtosecond fiber lasers can write versatile patterns of hydrophobicity with nanoscale precision on any metal. The results show that the homogeneously distributed hierarchical structures exhibit multifunctional properties, including superhydrophobicity, self-cleaning, and light-trapping. By optimizing the fabrication conditions, we have achieved a contact angle as high as 171° and a rolling angle of less than 3°. The structure is also resistant to an extreme temperature range of −40 °C to 71 °C and temperature shocks from 20 °C to −40 °C. This research highlights the exciting potential applications of superhydrophobic metals in the aviation, biomedical, and solar energy industries and beyond.

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Micro-, nano- and hierarchical structures for superhydrophobicity, self-cleaning and low adhesion

Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences ◽

10.1098/rsta.2009.0014 ◽

2009 ◽

Vol 367 (1894) ◽

pp. 1631-1672 ◽

Cited By ~ 503

Author(s):

Bharat Bhushan ◽

Yong Chae Jung ◽

Kerstin Koch

Keyword(s):

Contact Angle ◽

Low Cost ◽

Contact Angle Hysteresis ◽

Hierarchical Structures ◽

Adhesive Force ◽

Water Repellent ◽

Lotus Effect ◽

Composite State ◽

Static Contact ◽

Self Cleaning

Superhydrophobic surfaces exhibit extreme water-repellent properties. These surfaces with high contact angle and low contact angle hysteresis also exhibit a self-cleaning effect and low drag for fluid flow. Certain plant leaves, such as lotus leaves, are known to be superhydrophobic and self-cleaning due to the hierarchical roughness of their leaf surfaces. The self-cleaning phenomenon is widely known as the ‘lotus effect’. Superhydrophobic and self-cleaning surfaces can be produced by using roughness combined with hydrophobic coatings. In this paper, the effect of micro- and nanopatterned polymers on hydrophobicity is reviewed. Silicon surfaces patterned with pillars and deposited with a hydrophobic coating were studied to demonstrate how the effects of pitch value, droplet size and impact velocity influence the transition from a composite state to a wetted state. In order to fabricate hierarchical structures, a low-cost and flexible technique that involves replication of microstructures and self-assembly of hydrophobic waxes is described. The influence of micro-, nano- and hierarchical structures on superhydrophobicity is discussed by the investigation of static contact angle, contact angle hysteresis, droplet evaporation and propensity for air pocket formation. In addition, their influence on adhesive force as well as efficiency of self-cleaning is discussed.

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Ultrafast fiber laser-induced fabrication of superhydrophobic and self-cleaning metal surfaces

Applied Surface Science ◽

10.1016/j.apsusc.2020.148560 ◽

2021 ◽

Vol 542 ◽

pp. 148560

Author(s):

Sharjeel A. Khan ◽

Ganjaboy S. Boltaev ◽

Mazhar Iqbal ◽

V. Kim ◽

Rashid A. Ganeev ◽

...

Keyword(s):

Fiber Laser ◽

Metal Surfaces ◽

Self Cleaning

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Simultaneous Manipulation of the Optical and Wettability Properties of Metal Surfaces Using 150 kHz Femtosecond Fiber Laser

Applied Sciences ◽

10.3390/app10186207 ◽

2020 ◽

Vol 10 (18) ◽

pp. 6207

Author(s):

Mazhar Iqbal ◽

Vadim Ialyshev ◽

Vyacheslav Kim ◽

Ganjaboy Boltaev ◽

Dmitry Ivanov ◽

...

Keyword(s):

Femtosecond Laser ◽

Fiber Laser ◽

High Power ◽

Repetition Rate ◽

Laser Processing ◽

Metal Surfaces ◽

Processing Time ◽

Practical Applications ◽

Second Stage ◽

Femtosecond Fiber Laser

We demonstrate the formation of permanent and iridescent colors on aluminum, copper, steel, and brass surfaces using femtosecond laser-induced periodic and non-periodic nanostructuring. We show that both the permanent and iridescent colors of the metal surfaces can be erased and re-colored using a second stage of laser processing. A correlation was found between the spectral reflective properties of the laser-processed surfaces and their wettability properties. Transition from superhydrophilic to superhydrophobic response is observed while tailoring the optical reflectance of the metal surfaces. We employ a high power femtosecond fiber laser at 150 kHz repetition rate, which notably reduces the processing time, making this technique attractive for practical applications.

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