Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > Surface engineering: Imprinted cleanliness

Fig. 1: Etching a dense array of pits into the surface of a silicon substrate with a laser increases its water repellency. Using this surface as a template to imprint the reverse of this pattern into a sol–gel film results in a surface that is even more water repellent.

© 2009 A*STAR
Fig. 1: Etching a dense array of pits into the surface of a silicon substrate with a laser increases its water repellency. Using this surface as a template to imprint the reverse of this pattern into a sol–gel film results in a surface that is even more water repellent. © 2009 A*STAR

Abstract:
A laser-patterned template could enable self-cleaning surfaces to be grown over large areas at low cost.

Surface engineering: Imprinted cleanliness

Singapore | Posted on December 9th, 2009

The leaves of the lotus flower have a remarkable property—they are self-cleaning. Because the leaves are hydrophobic, or water repellent, water that comes into contact with them forms spherical beads that roll along the leaf picking up dust and dirt on from its surface. Now, a research group from the Singapore Institute of Manufacturing Technology of A*STAR have developed a method that could eventually enable large surface areas to be coated with a hydrophobic layer that mimics this self-cleaning property (1).

"Hydrophobic surfaces are desirable for many industrial applications such as anti-biofouling paints for boats, anti-sticking of snow for antennas and windows, self-cleaning windshields for automobiles, stain-resistant textiles and anti-soiling architectural coatings," explains Xincai Wang from the group.

Many techniques exist for making a surface hydrophobic. Coating a surface with chemicals that are naturally water repellent, for example, is one approach. However, this may not work for many surfaces. Moreover, such chemicals gradually degrade and are easily rubbed off, requiring continual retreatment. A more robust and longer-lasting approach is to change the microscopic structure of a surface. It is well known that structuring a surface to have micrometer-sized protrusions increases its water-repelling properties. But conventional techniques for patterning these structures, such as photolithography combined with reactive ion etching, are time-consuming and expensive.

The technique developed by Wang and co-workers produces hydrophobic surfaces that are robust and potentially much cheaper than those produced by photolithgraphic patterning. First, the researchers drilled a dense array of pits into a flat silicon substrate with a sharply focused, ultraviolet laser (Fig. 1). They found that this step on its own increased the hydrophobicity of the surface, causing water droplets on its surface to form a more spherical shape than on an untreated surface. Such behavior is typically quantified by measuring the angle made by the base of a droplet with the surface, known as the wetting angle, which in this case increased from 64.2° to 97.5°.

Next, Wang and co-workers used the silicon surface as a stamp to imprint the inverse of its pattern into the surface of a soft sol-gel film. Without modification, these films exhibited hydrophibicity with a contact angle of 110°. But imprinting them with the silicon stamp increased this to 138°.

In future work, the researchers intend to extend this approach to make hydrophobic surfaces over large areas on an industrial scale.

The A*STAR affiliated authors in this highlight are from the Singapore Institute of Manufacturing Technology

Reference
1 Wang, X.C., Wu, L.Y.L., Shao, Q. & Zheng, H.Y. Laser micro structuring on a Si substrate for improving surface hydrophobicity. Journal of Micromechanics and Microengineering 19, 085025 (2009).

####

About A*STAR
A*STAR Research is an online and print publication highlighting some of the best research and technological developments at the research institutes of Singapore’s Agency for Science, Technology and Research (A*STAR). Established in 2002, A*STAR has thrived as a global research organization with a principal mission of fostering world-class scientific research and talent for a vibrant knowledge-based Singapore. A*STAR currently oversees 14 research institutes as well as 7 consortia and centers located in the Biopolis and Fusionopolis complexes and the vicinity, and supports extramural research in collaboration with universities, hospital research centers and other local and international partners. The various A*STAR institutes are involved in research in a wide range of scientific fields, coordinated and funded by Singapore’s Biomedical Research Council (BMRC) and Science and Engineering Research Council (SERC).

For more information, please click here

Copyright © A*STAR

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

News and information

Sandia use confined nanoparticles to improve hydrogen storage materials performance: Big changes from a small package for hydrogen storage February 25th, 2017

New nano approach could cut dose of leading HIV treatment in half February 24th, 2017

Atom-scale oxidation mechanism of nanoparticles helps develop anti-corrosion materials February 24th, 2017

Atomic force imaging used to study nematodes: KFU bionanotechnology lab (head - Dr. Rawil Fakhrullin) has obtained 3-D images of nematodes' cuticles February 23rd, 2017

Particle Works creates range of high performance quantum dots February 23rd, 2017

Marine/Watercraft

Atom-scale oxidation mechanism of nanoparticles helps develop anti-corrosion materials February 24th, 2017

Transparent gel-based robots can catch and release live fish: Made from hydrogel, robots may one day assist in surgical operations, evade underwater detection February 2nd, 2017

Possible Futures

Sandia use confined nanoparticles to improve hydrogen storage materials performance: Big changes from a small package for hydrogen storage February 25th, 2017

New nano approach could cut dose of leading HIV treatment in half February 24th, 2017

Atom-scale oxidation mechanism of nanoparticles helps develop anti-corrosion materials February 24th, 2017

EmTech Asia breaks new barriers with potential applications of space exploration with NASA and MIT February 22nd, 2017

Materials/Metamaterials

Sandia use confined nanoparticles to improve hydrogen storage materials performance: Big changes from a small package for hydrogen storage February 25th, 2017

Atom-scale oxidation mechanism of nanoparticles helps develop anti-corrosion materials February 24th, 2017

EmTech Asia breaks new barriers with potential applications of space exploration with NASA and MIT February 22nd, 2017

Molecular phenomenon discovered by advanced NMR facility: Cutting edge technology has shown a molecule self-assembling into different forms when passing between solution state to solid state, and back again - a curious phenomenon in science - says research by the University of Wa February 22nd, 2017

Announcements

Sandia use confined nanoparticles to improve hydrogen storage materials performance: Big changes from a small package for hydrogen storage February 25th, 2017

New nano approach could cut dose of leading HIV treatment in half February 24th, 2017

Atom-scale oxidation mechanism of nanoparticles helps develop anti-corrosion materials February 24th, 2017

Atomic force imaging used to study nematodes: KFU bionanotechnology lab (head - Dr. Rawil Fakhrullin) has obtained 3-D images of nematodes' cuticles February 23rd, 2017

Environment

Meta-lenses bring benchtop performance to small, hand-held spectrometer: Game-changing nanostructure-based lenses allow smaller devices, increased functionality February 9th, 2017

NIST updates 'sweet' 1950s separation method to clean nanoparticles from organisms January 27th, 2017

Investigating the impact of natural and manmade nanomaterials on living things: Center for Environmental Implications of Nanotechnology develops tools to assess current and future risk January 9th, 2017

PCATDES Starts Field Testing of Photocatalytic Reactors in South East Asia December 28th, 2016

Construction

Graphene foam gets big and tough: Rice University's nanotube-reinforced material can be shaped, is highly conductive February 13th, 2017

New low-cost technique converts bulk alloys to oxide nanowires January 24th, 2017

Rice U probes ways to turn cement's weakness to strength: Rice University lab's calculations show new mechanisms to induce strength, ductility into concrete January 6th, 2017

Diamond nanothread: Versatile new material could prove priceless for manufacturing: Would you dress in diamond nanothreads? It's not as far-fetched as you might think November 3rd, 2016

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project