Nanotechnology Now





Heifer International

Wikipedia Affiliate Button


DHgate

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

Global Nano-Enabled Packaging Market For Food and Beverages Will Reach $15.0 billion in 2020 May 26th, 2015

Dr.Theivasanthi Slashes the Price of Graphene Heavily: World first & lowest price – Nano-price (30 USD / kg) of graphene by nanotechnologist May 26th, 2015

Fine-tuned molecular orientation is key to more efficient solar cells May 26th, 2015

DNA Double Helix Does Double Duty in Assembling Arrays of Nanoparticles: Synthetic pieces of biological molecule form framework and glue for making nanoparticle clusters and arrays May 25th, 2015

Marine/Watercraft

Enhanced Graphene Components for Next Generation Racing Yacht March 5th, 2015

BRAAVOO will design an unmanned surveying vessel and marine buoy that carry biosensors to monitor marine pollutants November 12th, 2014

First Observation of Electronic Structure in Ag-Rh Alloy Nanoparticles Having Hydrogen Absorbing: Storage Property –Attempting to solve the mystery of why Ag-Rh alloy nanoparticles have a similar property to Pd– October 30th, 2014

Engineered proteins stick like glue — even in water: New adhesives based on mussel proteins could be useful for naval or medical applications September 22nd, 2014

Possible Futures

Global Nano-Enabled Packaging Market For Food and Beverages Will Reach $15.0 billion in 2020 May 26th, 2015

Simulations predict flat liquid May 21st, 2015

Nature inspires first artificial molecular pump: Simple design mimics pumping mechanism of life-sustaining proteins found in living cells May 19th, 2015

NNCO and Museum of Science Fiction to Collaborate on Nanotechnology and 3D Printing Panels at Awesome Con May 19th, 2015

Materials/Metamaterials

Dr.Theivasanthi Slashes the Price of Graphene Heavily: World first & lowest price – Nano-price (30 USD / kg) of graphene by nanotechnologist May 26th, 2015

DNA Double Helix Does Double Duty in Assembling Arrays of Nanoparticles: Synthetic pieces of biological molecule form framework and glue for making nanoparticle clusters and arrays May 25th, 2015

Engineering Phase Changes in Nanoparticle Arrays: Scientists alter attractive and repulsive forces between DNA-linked particles to make dynamic, phase-shifting forms of nanomaterials May 25th, 2015

Nanostructures Increase Corrosion Resistance in Metallic Body Implants May 24th, 2015

Announcements

Global Nano-Enabled Packaging Market For Food and Beverages Will Reach $15.0 billion in 2020 May 26th, 2015

Dr.Theivasanthi Slashes the Price of Graphene Heavily: World first & lowest price – Nano-price (30 USD / kg) of graphene by nanotechnologist May 26th, 2015

Fine-tuned molecular orientation is key to more efficient solar cells May 26th, 2015

DNA Double Helix Does Double Duty in Assembling Arrays of Nanoparticles: Synthetic pieces of biological molecule form framework and glue for making nanoparticle clusters and arrays May 25th, 2015

Environment

Conversion of Greenhouse Gases to Syngas in Presence of Nanocatalysts in Iran May 22nd, 2015

Directa Plus in Barcelona to present the innovative project GEnIuS for oil spills clean-up activities: The company has created a graphene-based product for the remediation of water contaminated by oil and hydrocarbons May 21st, 2015

Nano-policing pollution May 13th, 2015

Chemists strike nano-gold: 4 new atomic structures for gold nanoparticle clusters: Research builds upon work by Nobel Prize-winning team from Stanford University April 28th, 2015

Construction

Iranian Scientists Present Model to Study Mechanical Vibrations of Structures Containing Nanocomposites May 5th, 2015

Nanoparticles Used to Improve Mechanical, Thermal Properties of Cellulose Fibers April 23rd, 2015

Blue Star Opportunities Corp. (BSTO) Completes Major Condo Building Project in Manhattan Residential Area; Company Now Has the Resources to Service the Largest of Construction Projects April 21st, 2015

To Conserve London's 300-Year-Old Masterpiece, Nanotech & Drones April 12th, 2015

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