{"215221":{"#nid":"215221","#data":{"type":"news","title":"Advanced Paper Could be Foundation for Inexpensive Biomedical and Diagnostic Devices","body":[{"value":"\u003Cp\u003EPaper is known for its ability to absorb liquids, making it ideal for products such as paper towels. But by modifying the underlying network of cellulose fibers, etching off surface \u201cfluff\u201d and applying a thin chemical coating, researchers have created a new type of paper that repels a wide variety of liquids \u2013 including water and oil.\u003C\/p\u003E\u003Cp\u003EThe paper takes advantage of the so-called \u0022lotus effect\u0022 \u2013 used by leaves of the lotus plant \u2013 to repel liquids through the creation of surface patterns at two different size scales and the application of a chemical coating. The material, developed at the Georgia Institute of Technology, uses nanometer- and micron-scale structures, plus a surface fluorocarbon, to turn old-fashioned paper into an advanced material.\u003C\/p\u003E\u003Cp\u003EThe modified paper could be used as the foundation for a new generation of inexpensive biomedical diagnostics in which liquid samples would flow along patterns printed on the paper using special hydrophobic ink and an ordinary desktop printer. This paper could also provide an improved packaging material that would be less expensive than other oil- and water-repelling materials, while being both recyclable and sustainable.\u003C\/p\u003E\u003Cp\u003E\u201cPaper is a very heterogeneous material composed of fibers with different sizes, different lengths and a non-circular cross-section,\u201d said \u003Ca href=\u0022http:\/\/www.chbe.gatech.edu\/faculty\/hess\u0022\u003EDennis Hess\u003C\/a\u003E, a professor in the Georgia Tech \u003Ca href=\u0022http:\/\/www.chbe.gatech.edu\/\u0022\u003ESchool of Chemical and Biomolecular Engineering\u003C\/a\u003E. \u201cWe believe this is the first time that a superamphiphobic surface \u2013 one that repels all fluids \u2013 has been created on a flexible, traditional and heterogeneous material like paper.\u201d\u003C\/p\u003E\u003Cp\u003EResearch leading to development of the superamphiphobic paper has been supported by the Institute for Paper Science and Technology (IPST) at Georgia Tech. Details were published online May 24 in the journal \u003Cem\u003EACS Applied Materials \u0026amp; Interfaces\u003C\/em\u003E.\u003C\/p\u003E\u003Cp\u003EThe new paper, which is both superhydrophobic (water-repelling) and super oleophobic (oil-repelling), can be made from standard softwood and hardwood fibers using a modified paper process. In addition to Hess, the research team included Lester Li, a graduate research assistant, and Victor Breedveld, an associate professor in the School of Chemical and Biomolecular Engineering\u003C\/p\u003E\u003Cp\u003EProducing the new paper begins with breaking up cellulose fibers into smaller structures using a mechanical grinding process. As in traditional paper processing, the fibers are then pressed in the presence of water \u2013 but then the water is removed and additional processing is done with the chemical butanol. Use of butanol inhibits the hydrogen bonding that normally takes place between cellulose fibers, allowing better control of their spacing.\u003C\/p\u003E\u003Cp\u003E\u201cThe desirable properties we are seeking are mainly controlled by the geometry of the fibers,\u201d Hess explained.\u003C\/p\u003E\u003Cp\u003EThe second step involves using an oxygen plasma etching process \u2013 a technique commonly used in the microelectronics industry \u2013 to remove the layer of amorphous \u201cfluffy\u201d cellulose surface material, exposing the crystalline cellulose nanofibrils. The process thereby uncovers smaller cellulose structures and provides a second level of \u201croughness\u201d with the proper geometry needed to repel liquids.\u003C\/p\u003E\u003Cp\u003EFinally, a thin coating of a fluoropolymer is applied over the network of cellulose fibers. In testing, the paper was able to repel water, motor oil, ethylene glycol and n-hexadecane solvent.\u003C\/p\u003E\u003Cp\u003EThe researchers have printed patterns onto their paper using a hydrophobic ink and a desktop printer. Droplets applied to the pattern remain on the ink pattern, repelled by the adjacent superamphiphobic surface.\u003C\/p\u003E\u003Cp\u003EThat capability could facilitate development of inexpensive biomedical diagnostic tests in which a droplet containing antigens could be rolled along a printed surface where it would encounter diagnostic chemicals. If appropriate reagents are used, the specific color or color intensity of the patterns could indicate the presence of a disease. Because the droplets adhere tightly to the printed lines or dots, the samples can be sent to a laboratory for additional testing.\u003C\/p\u003E\u003Cp\u003E\u201cWe have shown that we can do the operations necessary for a microfluidic device,\u201d Hess said. \u201cWe can move the droplet along a pattern, split the droplet and transfer the droplet from one piece of paper to another. We can do all of these operations on a two-dimensional surface.\u201d\u003C\/p\u003E\u003Cp\u003EFor Hess, Li and Breedveld, creating a superhydrophobic suface was relatively straightforward because water has a high surface tension. For oils, which have a low surface tension, the key to creating the repellent surface is to create re-entrant \u2013 or undercut \u2013 angles between the droplets and the surface.\u003C\/p\u003E\u003Cp\u003EPrevious examples of superamphiphobic surfaces have been made on rigid surfaces through lithographic techniques. Such processes tend to produce fragile surfaces that are prone to damage, Hess said.\u003C\/p\u003E\u003Cp\u003EThe principal challenge has been to create high-performance in a material that is anything but geometrically regular and consistent.\u003C\/p\u003E\u003Cp\u003E\u201cWorking with heterogeneous materials is fascinating, but it\u2019s very difficult not just to control them, because there is no inherent consistent structure, but also to change the processing conditions so you can get something that, on average, is what you need,\u201d he said. \u201cIt\u2019s been a real learning experience for us.\u201d\u003C\/p\u003E\u003Cp\u003EThe new paper has so far been made in samples about four inches on a side, but Hess sees no reason why the process couldn\u2019t be scaled up. Though long-term testing of the new paper hasn\u2019t been done, Hess is encouraged by what he\u2019s seen so far.\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003ECITATION\u003C\/strong\u003E: Lester Li, Victor Breedveld and Dennis Hess, \u201cDesign and Fabrication of Superamphiphobic Paper Surfaces,\u201d (ACS Applied Materials \u0026amp; Interfaces, 2013).\u003Cbr \/\u003E\u003Cbr \/\u003E\u003Cstrong\u003EResearch News\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003EGeorgia Institute of Technology\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003E177 North Avenue\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cstrong\u003EAtlanta, Georgia\u0026nbsp; 30332-0181\u003C\/strong\u003E\u003Cbr \/\u003E\u003Cbr \/\u003E\u003Cstrong\u003EMedia Relations Contact\u003C\/strong\u003E: John Toon (404-894-6986)(\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E).\u003C\/p\u003E\u003Cp\u003E\u003Cstrong\u003EWriter\u003C\/strong\u003E: John Toon\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":[{"value":"\u003Cp\u003EPaper is known for its ability to absorb liquids, making it ideal for products such as paper towels. But by modifying the underlying network of cellulose fibers, etching off surface \u201cfluff\u201d and applying a thin chemical coating, researchers have created a new type of paper that repels a wide variety of liquids \u2013 including water and oil.\u003C\/p\u003E","format":"limited_html"}],"field_summary_sentence":[{"value":"Researchers have created a new type of paper that repels a wide variety of liquids \u2013 including water and oil."}],"uid":"27303","created_gmt":"2013-05-28 13:42:12","changed_gmt":"2016-10-08 03:14:20","author":"John Toon","boilerplate_text":"","field_publication":"","field_article_url":"","dateline":{"date":"2013-05-28T00:00:00-04:00","iso_date":"2013-05-28T00:00:00-04:00","tz":"America\/New_York"},"extras":[],"hg_media":{"215171":{"id":"215171","type":"image","title":"Advanced Paper","body":null,"created":"1449180096","gmt_created":"2015-12-03 22:01:36","changed":"1475894879","gmt_changed":"2016-10-08 02:47:59","alt":"Advanced Paper","file":{"fid":"197087","name":"advanced-paper12.jpg","image_path":"\/sites\/default\/files\/images\/advanced-paper12_0.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/images\/advanced-paper12_0.jpg","mime":"image\/jpeg","size":1576403,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/advanced-paper12_0.jpg?itok=eZoQFmzk"}},"215181":{"id":"215181","type":"image","title":"Advanced Paper2","body":null,"created":"1449180096","gmt_created":"2015-12-03 22:01:36","changed":"1475894879","gmt_changed":"2016-10-08 02:47:59","alt":"Advanced Paper2","file":{"fid":"197088","name":"advanced-paper113.jpg","image_path":"\/sites\/default\/files\/images\/advanced-paper113_0.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/images\/advanced-paper113_0.jpg","mime":"image\/jpeg","size":1542667,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/advanced-paper113_0.jpg?itok=bAqHjbrb"}},"215191":{"id":"215191","type":"image","title":"Advanced Paper3","body":null,"created":"1449180096","gmt_created":"2015-12-03 22:01:36","changed":"1475894879","gmt_changed":"2016-10-08 02:47:59","alt":"Advanced Paper3","file":{"fid":"197089","name":"advanced-paper138.jpg","image_path":"\/sites\/default\/files\/images\/advanced-paper138_0.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/images\/advanced-paper138_0.jpg","mime":"image\/jpeg","size":477769,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/advanced-paper138_0.jpg?itok=ap3m7ddY"}},"215201":{"id":"215201","type":"image","title":"Advanced Paper4","body":null,"created":"1449180096","gmt_created":"2015-12-03 22:01:36","changed":"1475894879","gmt_changed":"2016-10-08 02:47:59","alt":"Advanced Paper4","file":{"fid":"197090","name":"advanced-paper164.jpg","image_path":"\/sites\/default\/files\/images\/advanced-paper164_0.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/images\/advanced-paper164_0.jpg","mime":"image\/jpeg","size":716154,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/advanced-paper164_0.jpg?itok=sHuRevkB"}},"215211":{"id":"215211","type":"image","title":"Advanced Paper5","body":null,"created":"1449180096","gmt_created":"2015-12-03 22:01:36","changed":"1475894879","gmt_changed":"2016-10-08 02:47:59","alt":"Advanced Paper5","file":{"fid":"197091","name":"advanced-paper213.jpg","image_path":"\/sites\/default\/files\/images\/advanced-paper213_0.jpg","image_full_path":"http:\/\/hg.gatech.edu\/\/sites\/default\/files\/images\/advanced-paper213_0.jpg","mime":"image\/jpeg","size":757515,"path_740":"http:\/\/hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/advanced-paper213_0.jpg?itok=vvBohpym"}}},"media_ids":["215171","215181","215191","215201","215211"],"groups":[{"id":"1188","name":"Research Horizons"}],"categories":[{"id":"141","name":"Chemistry and Chemical Engineering"}],"keywords":[{"id":"2548","name":"biomedical"},{"id":"42511","name":"Dennis Hess"},{"id":"10678","name":"diagnostic"},{"id":"67011","name":"lotus effect"},{"id":"2106","name":"Paper"},{"id":"167445","name":"School of Chemical and Biomolecular Engineering"},{"id":"169577","name":"superamphiphobic"}],"core_research_areas":[{"id":"39471","name":"Materials"},{"id":"39491","name":"Renewable Bioproducts"}],"news_room_topics":[],"event_categories":[],"invited_audience":[],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003EJohn Toon\u003C\/p\u003E\u003Cp\u003EResearch News\u003C\/p\u003E\u003Cp\u003E\u003Ca href=\u0022mailto:jtoon@gatech.edu\u0022\u003Ejtoon@gatech.edu\u003C\/a\u003E\u003C\/p\u003E\u003Cp\u003E(404) 894-6986\u003C\/p\u003E","format":"limited_html"}],"email":["jtoon@gatech.edu"],"slides":[],"orientation":[],"userdata":""}}}