Nanosurfaces. General Description. Program Objectives. Time Required. Organization: MRSEC University of Wisconsin. Contact person: Heidi Williamson

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Constance Wiggins
5 years ago
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1 Nanosurfaces Organization: MRSEC University of Wisconsin Contact person: Heidi Williamson Contact information: General Description With two different interactive activities we use the carnival/ circus theme to expose how nanotechnology has advanced common products. We demonstrate the self- cleaning principles behind the Lotus effect with a model, and follow the demonstration with an interactive activity that allows participants to see Lotus paint at work. We trick visitors into learning by letting them have fun while observing the nano-properties at work. Program Objectives Expose how nanotechnology can improve the materials in our everyday lives. Visitors will learn that scientists copied a surface in nature that protects leaves and used it to improve paint. Nano is both everyday and cutting edge. Where will nano go? It s different down there. Will nano affect you? Time Required Set-up Program Clean Up 5 minutes 10 minutes 5 minutes 1 March 20, 2007

2 Program/Demo Title Table of Contents GENERAL DESCRIPTION... 1 PROGRAM OBJECTIVES... 1 TIME REQUIRED... 1 TABLE OF CONTENTS... 2 BACKGROUND INFORMATION... 3 MATERIALS... 4 SET UP... 4 STEP 1:...ERROR! BOOKMARK NOT DEFINED. PROGRAM DELIVERY... 5 SAFETY:... 5 PROCEDURE AND DISCUSSION:... 5 TIPS AND TROUBLESHOOTING:... 5 COMMON VISITOR QUESTIONS... 5 GOING FURTHER...ERROR! BOOKMARK NOT DEFINED. CLEAN UP March 20, 2007

3 Background Information Everything is different at the nanoscale. Nanotechnology has begun entering products that we use everyday life, mostly in the form of surface treatments. Visitors may already be aware of stain-resistant Nano-Tex fabric, which exhibits hydrophobic (water-repellant or literally water-fearing ) properties. This activity explores Lotusan paint. The lotus effect, first noticed in the leaves of the lotus plant, is a self-cleaning, water repellant property found in some plants. Remarkably, despite constant exposure to dust, dirt, rain, and other elements, the leaves of the lotus plant remain clean and dry. Scientists have discovered that this is because the surface of each leaf contains nanometer-sized waxy bumps that prevent both dirt and water from adhering to it. Because the valleys between the bumps are too small for dirt particles to get into, the dirt stays suspended on the tops of the bumps. When a water droplet falls on the leaf, it is also suspended on top of the waxy bumps, and this creates a lot of surface tension. Water is a polar molecule, meaning that a water molecule likes to stick to, or pull on, other water molecules. The attraction that water molecules have towards each other is what causes water to bead up on a surface inside of a drop of water, each molecule of water is being pulled in every direction by all the other water molecules that surround it, so that the pull from the top cancels the pull from the bottom, the pull from the left cancels the pull from the right, and so on, but at the surface of the water drop, there is no pull from the outside, since there is no more water on the outside, so the water molecules at the surface are only pulled one way back into the drop. The pull back inwards toward the center of the drop is what s called surface tension, and this surface tension around the entire outside of a bead of water is the reason that the water drop ends up being spherical instead of flat. Because it is suspended on just the peaks of those nanoscale mountains, the water droplet is surrounded almost entirely by air, which creates a lot of surface tension and makes the water bead up even more and stick to the leaf even less. In fact, the water is so loosely stuck to its surface that the tiniest movement of the leaf will cause the beads of water to move, rolling smoothly off of the leaf and taking any dirt particles that they roll over with them this makes the leaves self-cleaning. This same nano-mountain lotus leaf structure has been recreated in a product called Lotusan paint. Buildings painted with Lotusan are self-cleaning every time it rains and the surface of the building always stays dry due to the lotus effect, preventing leaks. Through new advances in nanotechnology, scientists are also discovering ways to create other materials with a microscopically bumpy surface that mimics the lotus leaf surface. They re 3 March 20, 2007

4 hoping to make all kinds of self-cleaning and super-non-stick materials, such as self-cleaning windows, non-stick medical devices that will prevent cells from sticking and forming blood clots, and kitchenware that can simply be rinsed and reused because food and other contamination can t stick to it. Materials Activity: Model: Set Up Water guns or deck sprayers Water Surface painted with regular white house paint Surface painted with Lotusan paint Dirt Tubs to catch water Magnetic water pieces Bumpy Lotus surface board Smooth surface board Graphic poster Time: 5-10 minutes Stand surfaces painted with lotusan and regular paint inside of tubs Fill deck sprayers with water- be sure to pump a few times before using Prop surface model in stands and display graphic 4 March 20, 2007

5 Program Delivery Time: 5-10 minutes Safety: Very safe- make sure water sprayers are supervised Procedure and Discussion: Come one come all and see the difference nanotechnology brings! Can you tell which paint has special nano properties? Stop and look closely very, very closely and you can seek the answers to these amazing acts of wonder! Lotus Model: Gently throw water molecule magnets onto smooth surface of model. They will attach because they are attracted to the surface. Throw the same molecule magnets onto the other side representing the Lotus surface. The lotus effect will be represented when they roll off because of the bumpy surface. Lotus Interactive: Two panels of siding (similar look to house siding) are placed 4 to 5 feet from a table with two deck sprayers mounted to its top. One wall is painted with common latex exterior grade house paint. The other is painted with Lotusan paint. The volunteer rubs dirt onto the panels preparing the panels for the competition. Two visitors are asked to race and clean the dirt from the panels by shooting water at them and rinsing the panel clean. The Lotusan panel should clean easily while the other is more difficult to clean. Tips and Troubleshooting: Water has potential to be messy- have cleaning materials nearby Research application method of Lotus paint to make sure application and curing processes are correct. Clean Up Time: 5 minutes Wipe down painted surfaces- clear away any remaining dirt. Dump out tubs and deck sprayers. 5 March 20, 2007

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