Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

New microscope sets a record for visualizing surface wetting properties

28.11.2017

The microscope is 1,000 times more precise than current techniques, allowing the creation of wetting maps as a new concept for hydrophobic surface characterization

Wetting is an everyday phenomenon that represents how well liquid spreads on a surface. When water comes into contact with an extremely water-repellent, or 'superhydrophobic' surface, droplets bead up and roll off easily. Aalto University researchers have developed a measurement technique called Scanning Droplet Adhesion Microscopy (SDAM) to understand and characterize the wetting properties of superhydrophobic materials.


The droplet probe of the microscope on a superhydrophobic golden birdwing (Troides aeacus) butterfly wing.

Credit: Matti Hokkanen / Aalto University

"Our novel microscope will promote the understanding of how wetting emerges from surface microstructures. The measuring instrument can also detect microscopic defects of the surface, which could allow coating manufacturers to control the quality of materials.

Defects in self-cleaning, anti-icing, anti-fogging, anti-corrosion or anti-biofouling products can impeach the functional integrity of the whole surface," explains Professor Robin Ras from Aalto University School of Science.

SDAM is extremely sensitive and 1000 times more precise than the current state-of-the-art wetting characterization methods. It also has the ability to measure minuscule features and inconsistencies of surfaces with microscale resolution. Existing instruments for measuring droplet adhesion forces only detect forces down to a micronewton level - not sensitive enough for superhydrophobic surfaces.

"We have used a droplet of water to measure the water-repellent properties of a surface by recording the very tiny nanonewton force when the droplet touches the surface and when it separates from the surface. By measuring on many locations with micrometer spacing between the measurement points, we can construct a two-dimensional image of the surface's repellency, called a wetting map," explains Professor Quan Zhou from Aalto University School of Electrical Engineering.

Wetting maps are a new concept for hydrophobic surface characterization and open a window for investigating structure-property relationships in surface wetting.

Up to now, 'contact angle measurement' has been the typical method of measuring wetting properties of surfaces. It is prone to inaccuracies, though, for surfaces that are highly repellent to liquid. Unlike contact angle measurement, SDAM does not require a direct line of sight, which allows measuring uneven surfaces such as fabrics or biological surfaces. SDAM can also detect wetting properties of microscopic functional features that were previously very hard to measure. Those microscopic features are important in many biochips, chemical sensors and microelectromechanical components and systems.

###

The research is conducted by an interdisciplinary team from three schools of Aalto University: School of Electrical Engineering, School of Science, and School of Chemical Technology. The researchers involved in the study are Ville Liimatainen, Maja Vuckovac, Ville Jokinen, Veikko Sariola, Matti Hokkanen, Quan Zhou and Robin Ras.

More information:

The article "Mapping microscale wetting variations on biological and synthetic water-repellent surfaces" has been published today in Nature Communications.

Liimatainen V., Vuckovac M., Jokinen V., Sariola V., Hokkanen M., Zhou Q., Ras R.H.A., Mapping microscale wetting variations on biological and synthetic water-repellent surfaces, Nature Communications (2017) 1798. http://dx.doi.org/10.1038/s41467-017-01510-7

Robin Ras
Professor
Aalto University
Department of Applied Physics & Department of Bioproducts and Biosystems
robin.ras@aalto.fi
tel. +358 50 432 6633
http://physics.aalto.fi/smw

Quan Zhou
Professor
Aalto University
Department of Electrical Engineering and Automation
quan.zhou@aalto.fi
tel. +358 40 855 0311
http://eea.aalto.fi/en/research/micronanorobotics/

Robin Ras | EurekAlert!

Further reports about: droplet microscopic surfaces synthetic water-repellent

More articles from Materials Sciences:

nachricht Research finds new molecular structures in boron-based nanoclusters
13.07.2018 | Brown University

nachricht 3D-Printing: Support structures to prevent vibrations in post-processing of thin-walled parts
12.07.2018 | Fraunhofer-Institut für Produktionstechnologie IPT

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Behavior-influencing policies are critical for mass market success of low carbon vehicles

17.07.2018 | Power and Electrical Engineering

Plant mothers talk to their embryos via the hormone auxin

17.07.2018 | Life Sciences

Subaru Telescope helps pinpoint origin of ultra-high energy neutrino

16.07.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>