Aerospace Applications in Nanotechnology

Nanotechnology What Are The Uses of Hydrophobic Coatings? 2

Hydrophobic (adj): resistant to or avoiding wetting 3

Hydrophobic properties have been seen in nature since the beginning of time. Water droplets falling onto plant leaves roll off the leaves as seen in the photo below. cc by Ralph P.

In this artist’s rendering, we see that the surface of leaves have small hair-like strands that are covered with a waxy substance. This keeps the water droplets from absorbing into the leaf. cc by William Thielicke 5

Scientists today are able to simulate the natural hydrophobic properties using nanotechnology. By applying a thin coating of hydrophobic substances, we are able to create surfaces that are water-resistant. The glasses below have been treated with a hydrophobic product from Aculon, Inc. Images ©Aculon Before treatment After treatment

Hydrophobic leaf with a water droplet rolling off the surface. cc by Andrew Cannon Hydrophobic leaf with a water droplet rolling off the surface. The graphic on the left shows that the solid on which the liquid is laid is non-hydrophobic, the middle graphic is hydrophobic, and the graphic on the right shows super hydrophobic. cc by Michael Apel 7

Hydrophobic coatings are being used in many different areas: Aerospace Wood construction Monument protection Automobile windshields Graffiti cleanup

Graffiti Cleanup The effort to clean up graffiti around the world costs over a billion dollars annually. Companies such as Advanced Graffiti Solutions are developing and using products made using nanotechnology to treat walls and buildings so graffiti can simply be wiped off. cc by Sry85

Products such as spray coatings and paint have been developed to treat structures so the graffiti can be wiped off with little effort. The coating adheres to the stone or cement and does not allow the graffiti materials to attach to the wall. Follow the link below for videos showing the products at work. http://www.youtube.com/watch?v=Rp4vkY5kgTA&feature=related

Water Resistant Coating Many companies, such as Turtle Wax™, have developed a wax that adheres to the surface of a car and makes the paint completely resistant to environmental contaminants. http://www.youtube.com/watch?v=e5rGovKcEYY&NR=1

Monument Protection Much of the damage to protected monuments around the world is caused by weather. Using nanotechnology, a protective coating can be applied to the monuments to protect them from the elements. Nanotechnology prevents water from seeping into the crevices and freezing to cause cracks and damage. cc by Luis Garcia

Wood Protection Wood, when sprayed with a protective coating, will not burn. In the pictures, the board on the right is burning. The board on the left looks to be charred, but the charring scrapes off with ease. http://www.youtube.com/watch?v=q7ZwQlCcN-g&NR=1

A nano protective coating also makes wood water-resistant. http://www.youtube.com/watch?v=EmW4TZsZLI0&feature=related

Windshield Protection Chemsultants International has developed a coating that is applied to a windshield. With the coating, the surface becomes resistant to environmental elements. http://www.youtube.com/watch?v=96iMj5NSyyY&feature=relate

Hydrophobic coatings using nanotechnology are helping in the aerospace industry by making airplane wings resistant to water and ice coatings. Many airplane crashes have been attributed to ice on the wings before and during flight. Image courtesy Purdue

In this classroom activity, we will simulate how a hydrophobic coating applied to the wings of a gliders will affect its flight. Using balsa wood materials and instructions, build two identical gliders. Image by HighPoint Learning

Image by HighPoint Learning On one of the gliders, spray at least five coats of a protective coating, allowing the wood to dry in between coats. 18

Images by HighPoint Learning After spraying the gliders, weigh each glider with a digital gram scale. Notice there is only a small difference in the weight.

Sprinkle water on both wings of each glider, and then place them in the freezer and leave overnight. After 24 hours, take the gliders out of the freezer and immediately launch them. Observe the difference between their flights. 20

This module is one of a series designed to introduce faculty and high school students to the basic concepts of nanotechnology. Each module includes a PowerPoint presentation, discussion questions, and hands-on activities, when applicable.   The series was funded in part by:   The National Science Foundation Grant DUE-0702976 and the Oklahoma Nanotechnology Education Initiative   Any opinions, findings and conclusions or recommendations expressed in the material are those of the author and do not necessarily reflect the views of the National Science Foundation or the Oklahoma Nanotechnology Education Initiative.  

Image Credits P. , Ralf. (Photographer). Lotus Effect [Photograph] Image Credits   P., Ralf. (Photographer). Lotus Effect [Photograph]. Switzerland. Wikimedia Commons. (commons.wikimedia.org) Thielicke, William. (Artist). Lotus3.jpg [Computer rendering]. Germany. Wikimedia Commons. (commons.wikimedia.org) Cannon, Andrew H. (Designer). Microstruct superhydrophobic.png [diagram]. Wikimedia Commons. (commons.wikimedia.org) Apel, Michael. (Photographer). Dew drop on a leaf [Photograph]. Wikimedia Commons. (commons.wikimedia.org) Sry85 (Photographer). Tagging in Thailand. [Photograph]. Thailand. Wikimedia Commons. (commons.wikimedia.org) Garcia, Luis (Photographer). Monumento a Fray Pedro Ponce [Photograph of Monument]. Spain. Wikimedia Commons (commons.wikimedia.org) Wing Icing [Photograph]. United States. Aviation Educaton Multimedia Library (http://www2.tech.purdue.edu/at/courses/aeml/)

References Chandler, David. (2010) References   Chandler, David. (2010). Frost-Free Planes: Back to the Drawing Board. MIT News. Retrieved from http://web.mit.edu/newsoffice/2010/frost-formation-1222.html Samyn, P., Schoukens, G. Van den Abbeele, H., Vonck, L., Stanssens, D. (2010). Application of polymer nanoparticle coating for tuning the hydrophobicity of cellulosic substrates. Journal of Coatings Technology and Research. Issue 1547-0091. Pages 1-11.] Seung-Mo Lee and Tai Hun Kwon. Mass-producible replication of highly hydrophobic surfaces from plant leaves. NanoWerk. Retrieved from http://www.nanowerk.com/spotlight/spotid=644.php Wilson, Michael, Kanangara, Kamali, Smith, Geoff, Simmons, Michelle, & Raguse, Burkhard. Nanotechnology: Basic Science and Emerging Technologies. (2004). [Kindle Edition] Retrieved from http://www.amazon.com