{"id":9721,"date":"2015-01-23T01:47:31","date_gmt":"2015-01-23T06:47:31","guid":{"rendered":"http:\/\/hobbyspace.com\/Blog\/?p=9721"},"modified":"2015-01-23T01:47:31","modified_gmt":"2015-01-23T06:47:31","slug":"sci-tech-super-water-repellent-metal-surfaces-created-with-lasers","status":"publish","type":"post","link":"https:\/\/hobbyspace.com\/Blog\/?p=9721","title":{"rendered":"Sci-Tech: Super water-repellent metal surfaces created with lasers"},"content":{"rendered":"<p>A team at the University of Rochester has created a new laser etching technique that makes metal surfaces amazingly water repellent:<\/p>\n<p style=\"text-align: center;\"><strong><a href=\"http:\/\/www.rochester.edu\/newscenter\/superhydrophobic-metals-85592\/\" target=\"_d\">Laser-generated surface structures create<br \/>\nextremely water-repellent metals <\/a><\/strong><\/p>\n<p><span class=\"embed-youtube\" style=\"text-align:center; display: block;\"><iframe loading=\"lazy\" class=\"youtube-player\" width=\"1600\" height=\"900\" src=\"https:\/\/www.youtube.com\/embed\/FLegmQ8_dHg?version=3&#038;rel=1&#038;showsearch=0&#038;showinfo=1&#038;iv_load_policy=1&#038;fs=1&#038;hl=en&#038;autohide=2&#038;wmode=transparent\" allowfullscreen=\"true\" style=\"border:0;\" sandbox=\"allow-scripts allow-same-origin allow-popups allow-presentation allow-popups-to-escape-sandbox\"><\/iframe><\/span><\/p>\n<p>Scientists at the University of Rochester have used lasers to transform metals into extremely water repellent, or super-hydrophobic, materials without the need for temporary coatings.<\/p>\n<p>Super-hydrophobic materials are desirable for a number of applications such as rust prevention, anti-icing, or even in sanitation uses. However, as Rochester\u2019s Chunlei Guo explains, most current hydrophobic materials rely on chemical coatings.<\/p>\n<p>In <a title=\"JAP article\" href=\"http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/3\/10.1063\/1.4905616\" target=\"_blank\">a paper<\/a> published today in the Journal of Applied Physics, Guo and his colleague at the University\u2019s Institute of Optics, Anatoliy Vorobyev, describe a powerful and precise laser-patterning technique that creates an intricate pattern of micro- and nanoscale structures to give the metals their new properties. This work builds on earlier research by the team in which they used a similar laser-patterning technique that turned <a title=\"Turning metals black\" href=\"http:\/\/www.rochester.edu\/news\/show.php?id=2701\" target=\"_blank\">metals black<\/a>. Guo states that using this technique they can create multifunctional surfaces that are not only super-hydrophobic but also highly-absorbent optically.<\/p>\n<p>Guo adds that one of the big advantages of his team\u2019s process is that \u201cthe structures created by our laser on the metals are intrinsically part of the material surface.\u201d That means they won\u2019t rub off. And it is these patterns that make the metals repel water.<\/p>\n<p>\u201cThe material is so strongly water-repellent, the water actually gets bounced off. Then it lands on the surface again, gets bounced off again, and then it will just roll off from the surface,\u201d said Guo, professor of optics in the University\u2019s Hajim School of Engineering and Applied Sciences. That whole process takes less than a second.<\/p>\n<p>The materials Guo has created are much more slippery than Teflon\u2014a common hydrophobic material that often coats nonstick frying pans. Unlike Guo\u2019s laser-treated metals, the Teflon kitchen tools are not super-hydrophobic. The difference is that to make water to roll-off a Teflon coated material, you need to tilt the surface to nearly a 70-degree angle before the water begins to slide off. You can make water roll off Guo\u2019s metals by tilting them less than five degrees.<\/p>\n<p>As the water bounces off the super-hydrophobic surfaces, it also collects dust particles and takes them along for the ride. To test this self-cleaning property, Guo and his team took ordinary dust from a vacuum cleaner and dumped it onto the treated surface. Roughly half of the dust particles were removed with just three drops of water. It took only a dozen drops to leave the surface spotless. Better yet, it remains completely dry.<\/p>\n<p>Guo is excited by potential applications of super-hydrophobic materials in developing countries. It is this potential that has piqued the interest of the Bill and Melinda Gates Foundation, which has supported the work.<\/p>\n<p>\u201cIn these regions, collecting rain water is vital and using super-hydrophobic materials could increase the efficiency without the need to use large funnels with high-pitched angles to prevent water from sticking to the surface,\u201d says Guo. \u201cA second application could be creating latrines that are cleaner and healthier to use.\u201d<\/p>\n<p>Latrines are a challenge to keep clean in places with little water. By incorporating super-hydrophobic materials, a latrine could remain clean without the need for water flushing.<\/p>\n<p>But challenges still remain to be addressed before these applications can become a reality, Guo states. It currently takes an hour to pattern a 1 inch by 1 inch metal sample, and scaling up this process would be necessary before it can be deployed in developing countries. The researchers are also looking into ways of applying the technique to other, non-metal materials.<\/p>\n<p>Guo and Vorobyev use extremely powerful, but ultra-short, laser pulses to change the surface of the metals. A femtosecond laser pulse lasts on the order of a quadrillionth of a second but reaches a peak power equivalent to that of the entire power grid of North America during its short burst.<\/p>\n<p>Guo is keen to stress that this same technique can give rise to multifunctional metals. Metals are naturally excellent reflectors of light. That\u2019s why they appear to have a shiny luster. Turning them black can therefore make them very efficient at absorbing light. The combination of light-absorbing properties with making metals water repellent could lead to more efficient solar absorbers \u2013 solar absorbers that don\u2019t rust and do not need much cleaning.<\/p>\n<p>Guo\u2019s team had previously blasted materials with the lasers and turned them hydrophilic, meaning they attract water. In fact, the materials were so hydrophilic that putting them in contact with a drop of water made <a title=\"Hydrophilic materials\" href=\"http:\/\/www.rochester.edu\/news\/show.php?id=3387)\" target=\"_blank\">water run \u201cuphill.<\/a>\u201d<\/p>\n<p>Guo\u2019s team is now planning on focusing on increasing the speed of patterning the surfaces with the laser, as well as studying how to expand this technique to other materials such as semiconductors or dielectrics, opening up the possibility of water repellent electronics.<\/p>\n<p>Funding was provided by the Bill &amp; Melinda Gates Foundation and the United States Air Force Office of Scientific Research.<\/p>\n<p>The article, \u201cMultifunctional surfaces produced by femtosecond laser pulses,\u201d was published in the <em>Journal of Applied Physics<\/em> on January 20, 2015 (DOI: 10.1063\/1.4905616). It can be accessed at: http:\/\/scitation.aip.org\/content\/aip\/journal\/jap\/117\/3\/10.1063\/1.4905616<\/p>\n<p><a href=\"http:\/\/hobbyspace.com\/Blog\/wp-content\/uploads\/2015\/01\/2013-12-19_chunlei_drops_0421.jpg\"><img loading=\"lazy\" decoding=\"async\" data-attachment-id=\"9722\" data-permalink=\"https:\/\/hobbyspace.com\/Blog\/?attachment_id=9722\" data-orig-file=\"https:\/\/hobbyspace.com\/Blog\/wp-content\/uploads\/2015\/01\/2013-12-19_chunlei_drops_0421.jpg\" data-orig-size=\"2367,1576\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;32&quot;,&quot;credit&quot;:&quot;J. Adam Fenster \/ University of&quot;,&quot;camera&quot;:&quot;NIKON D4&quot;,&quot;caption&quot;:&quot;University of Rochester Institute of Optics professor Chunlei Guo has developed a technique that uses lasers to render materials hydrophobic, illustrated in these images taken in his lab December 19, 2013.  \/\/ photo by J. Adam Fenster \/ University of Rochester&quot;,&quot;created_timestamp&quot;:&quot;1387488994&quot;,&quot;copyright&quot;:&quot;University of Rochester&quot;,&quot;focal_length&quot;:&quot;105&quot;,&quot;iso&quot;:&quot;320&quot;,&quot;shutter_speed&quot;:&quot;0.004&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"2013-12-19_chunlei_drops_042[1]\" data-image-description=\"&lt;p&gt;University of Rochester Institute of Optics professor Chunlei Guo has developed a technique that uses lasers to render materials hydrophobic, illustrated in these images taken in his lab December 19, 2013.  \/\/ photo by J. Adam Fenster \/ University of Rochester&lt;\/p&gt;\n\" data-image-caption=\"\" data-large-file=\"https:\/\/hobbyspace.com\/Blog\/wp-content\/uploads\/2015\/01\/2013-12-19_chunlei_drops_0421-1024x682.jpg\" class=\"aligncenter wp-image-9722 size-large\" src=\"http:\/\/hobbyspace.com\/Blog\/wp-content\/uploads\/2015\/01\/2013-12-19_chunlei_drops_0421-1024x682.jpg\" alt=\"2013-12-19_chunlei_drops_042[1]\" width=\"520\" height=\"346\" srcset=\"https:\/\/hobbyspace.com\/Blog\/wp-content\/uploads\/2015\/01\/2013-12-19_chunlei_drops_0421-1024x682.jpg 1024w, https:\/\/hobbyspace.com\/Blog\/wp-content\/uploads\/2015\/01\/2013-12-19_chunlei_drops_0421-300x200.jpg 300w\" sizes=\"auto, (max-width: 520px) 100vw, 520px\" \/><\/a><\/p>\n<p style=\"padding-left: 30px;\"><em>Professor Chunlei Guo has developed a technique that uses lasers to render materials hydrophobic, illustrated in this image of a water droplet bouncing off a treated sample. Photo by J. Adam Fenster \/ University of Rochester<\/em><\/p>\n","protected":false},"excerpt":{"rendered":"<p>A team at the University of Rochester has created a new laser etching technique that makes metal surfaces amazingly water repellent: Laser-generated surface structures create extremely water-repellent metals Scientists at the University of Rochester have used lasers to transform metals into extremely water repellent, or super-hydrophobic, materials without the need for temporary coatings. Super-hydrophobic materials &hellip; <a href=\"https:\/\/hobbyspace.com\/Blog\/?p=9721\" class=\"more-link\">Continue reading <span class=\"screen-reader-text\">Sci-Tech: Super water-repellent metal surfaces created with lasers<\/span> <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_feature_clip_id":0,"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_post_was_ever_published":false},"categories":[9],"tags":[],"class_list":["post-9721","post","type-post","status-publish","format-standard","hentry","category-science-and-technology"],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p34aWK-2wN","jetpack-related-posts":[{"id":3475,"url":"https:\/\/hobbyspace.com\/Blog\/?p=3475","url_meta":{"origin":9721,"position":0},"title":"Sci-Tech: Ultra-dense deuterium packs tightly","author":"TopSpacer","date":"July 17, 2013","format":false,"excerpt":"A\u00a0 group led by Prof. Leif Holmlid at the\u00a0 University of Gothenburg, Sweden has created a really bizarre material: Ultra-dense deuterium may be the nuclear fuel of the future Material that is a hundred thousand times heavier than water and more dense than the core of the Sun is being\u2026","rel":"","context":"In &quot;Science and Technology&quot;","block_context":{"text":"Science and Technology","link":"https:\/\/hobbyspace.com\/Blog\/?cat=9"},"img":{"alt_text":"","src":"","width":0,"height":0},"classes":[]},{"id":10852,"url":"https:\/\/hobbyspace.com\/Blog\/?p=10852","url_meta":{"origin":9721,"position":1},"title":"Sci-Tech: 3D projected interactive objects created with femtosecond lasers","author":"TopSpacer","date":"June 28, 2015","format":false,"excerpt":"Here's a story about a neat 3D projection display technology that just might make it to market:\u00a0This Touchable Midair 3D Laser Display Is Pretty Magical - Singularity HUB\u00a0- https:\/\/youtu.be\/AoWi10YVmfE","rel":"","context":"In &quot;Science and Technology&quot;","block_context":{"text":"Science and Technology","link":"https:\/\/hobbyspace.com\/Blog\/?cat=9"},"img":{"alt_text":"","src":"https:\/\/i0.wp.com\/img.youtube.com\/vi\/AoWi10YVmfE\/0.jpg?resize=350%2C200","width":350,"height":200},"classes":[]},{"id":24985,"url":"https:\/\/hobbyspace.com\/Blog\/?p=24985","url_meta":{"origin":9721,"position":2},"title":"Videos: \u201cSpace to Ground\u201d &#038; 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