{"id":8758,"date":"2014-09-12T11:37:19","date_gmt":"2014-09-12T16:37:19","guid":{"rendered":"http:\/\/college.unc.edu\/?p=8758"},"modified":"2024-07-02T14:42:08","modified_gmt":"2024-07-02T14:42:08","slug":"dont-force-it-heat-light-or-sound-is-all-it-takes-to-turn-these-objects-into-something-new","status":"publish","type":"post","link":"https:\/\/collegearchive.unc.edu\/?p=8758","title":{"rendered":"Don’t Force It: Heat, light, or sound is all it takes to turn these objects into something new"},"content":{"rendered":"
\"These<\/a>
These are the first nonliving objects that can shift back and forth between two shapes without any external force being applied.<\/figcaption><\/figure>\n

B<\/span>end it, stretch it, squish it flat. To make something into the shape you want, you have to use force. Maybe a lot of force, like chopping firewood with an axe\u2014or maybe just a little, like pressing your thumb into wet clay. Either way, you\u2019re using\u00a0force.<\/p>\n

Not with the stuff in\u00a0UNC<\/span>\u00a0chemist Sergei Sheiko\u2019s lab. For the first time, his team has figured out how to make objects shift back and forth between two programmed shapes, over and over again, without applying any kind of force. This technology, he says, could someday change how we do surgery, pack things for shipment, and even how we fly\u00a0planes.<\/p>\n

http:\/\/vimeo.com\/104432862<\/p>\n

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These polymers are \u201csimply smaller molecules connected in a linear chain,\u201d Sheiko says. Because polymers are made up of molecular chains instead of rigid structures, they can be highly flexible, easily adopting various shapes without\u00a0fracturing.<\/p>\n

\"Left<\/a>
Left side: Semi-crystalline polymers, cooled. Right side: Polymers warmed up, melted, and ready to form a new shape.<\/figcaption><\/figure>\n

First, Sheiko says, you mold polymers into a certain shape, like a tube. Second, you warm the tube up to melt the microscopic crystals inside it. The tube becomes soft, like a rubber band, and you bend it into the shape you want, such as a coil. Third, you decrease the temperature, so the molecules crystallize and cement the new shape.<\/p>\n

Now, whenever you increase the coil\u2019s temperature, melting some\u2014but not all\u2014of its semi-crystalline structure, the coil returns to the tube form. Decrease the temperature, and the remaining crystals serve as a template to change to the coiled form. The lab of Department of Chemistry Chair Valerie Ashby worked on the chemical composition of the polymers to let the scientists choose which temperatures would make the shapes change form.<\/p>\n

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Using this idea, scientists could make a surgical stent, for example. Start out with a narrow tube. Then raise it to 98.6 degrees\u2014the temperature of the human body\u2014and bend it into a round shape to shore up the walls of an artery. Bring it back down to room temperature, and it\u2019s a tube\u00a0again.<\/p>\n

Because the stent starts out as a narrow tube, a surgeon could insert it in a minimally invasive way. Then the patient\u2019s body heat would bring it back to the stent shape once it was\u00a0inside.<\/p>\n

http:\/\/vimeo.com\/104336981<\/p>\n

The\u00a0U.S.<\/span>\u00a0military is interested in shape-shifting, Sheiko says, for all kinds of reasons. Sheiko grabs a magazine off his desk. \u201cImagine I can put a piece of paper under your door and increase the temperature or shine some light on it, and it assembles into some kind of a device,\u201d he\u00a0says.<\/p>\n

Or imagine a plane with shape-shifting wings. \u201cIf you look at birds like hawks or eagles, they change the geometry of their wings,\u201d Sheiko says. \u201cIf they want to fly and look for prey, their wings have one geometry, but the geometry changes when they\u00a0attack.\u201d<\/p>\n

And imagine if all these complex shape transformations were trigged remotely. Instead of using temperature, the lab has also used certain wavelengths of sound, magnets, and light waves to trigger a material to\u00a0change.<\/p>\n

Sheiko thinks that soft-matter science\u2014the study of polymers and other soft materials like liquid crystals, gels, and foams\u2014will be the nuclear physics of the twenty-first century: a new frontier of scientific discovery. There are fundamental principles we don\u2019t yet understand about how molecules such as polymers self-organize and are held together by weak forces to work in a\u00a0system.<\/p>\n

\u201cThe ultimate example of this,\u201d Sheiko says, \u201cis the human\u00a0body.\u201d<\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n

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Sergei Sheiko is the George A. Bush Jr. Distinguished Professor in the Department of Chemistry in the College of Arts and Sciences. Valerie Ashby, chair of the Department of Chemistry, was a coauthor of the paper describing shape-shifting polymers. OtherUNC<\/span>\u00a0coauthors were chemistry postdoc Jing Zhou, chemistry grad student Sarah Turner, physics grad student Qiaoxi Li, and former chemistry research associate Sarah\u00a0Brosnan.<\/p>\n

Their work is supported by the National Science Foundation. Their collaborators at the Brookhaven National Laboratory are supported by the\u00a0U.S.<\/span>\u00a0Department of Energy, Office of Basic Energy\u00a0Sciences.<\/p>\n

All images and videos provided courtesy of the Sheiko Group.\u00a0<\/em><\/p>\n

By Susan Hardy, Endeavors<\/a><\/p>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n<\/div>\n","protected":false},"excerpt":{"rendered":"

Bend it, stretch it, squish it flat. To make something into the shape you want, you have to use force. Maybe a lot of force, like chopping firewood with an axe\u2014or maybe just a little, like pressing your thumb into wet clay. Either way, you\u2019re using force.<\/p>\n","protected":false},"author":4,"featured_media":8761,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"site-sidebar-layout":"default","site-content-layout":"","ast-site-content-layout":"default","site-content-style":"default","site-sidebar-style":"default","ast-global-header-display":"","ast-banner-title-visibility":"","ast-main-header-display":"","ast-hfb-above-header-display":"","ast-hfb-below-header-display":"","ast-hfb-mobile-header-display":"","site-post-title":"","ast-breadcrumbs-content":"","ast-featured-img":"","footer-sml-layout":"","ast-disable-related-posts":"","theme-transparent-header-meta":"","adv-header-id-meta":"","stick-header-meta":"","header-above-stick-meta":"","header-main-stick-meta":"","header-below-stick-meta":"","astra-migrate-meta-layouts":"default","ast-page-background-enabled":"default","ast-page-background-meta":{"desktop":{"background-color":"var(--ast-global-color-4)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"ast-content-background-meta":{"desktop":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"tablet":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""},"mobile":{"background-color":"var(--ast-global-color-5)","background-image":"","background-repeat":"repeat","background-position":"center center","background-size":"auto","background-attachment":"scroll","background-type":"","background-media":"","overlay-type":"","overlay-color":"","overlay-opacity":"","overlay-gradient":""}},"footnotes":""},"categories":[17,21,1],"tags":[24,26,467,2391,36,1002],"class_list":["post-8758","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-natural-sciences-mathematics","category-news","category-uncategorized","tag-carolina","tag-college-of-arts-and-sciences","tag-sergei-sheiko","tag-sheiko","tag-unc","tag-university-of-north-carolina"],"_links":{"self":[{"href":"https:\/\/collegearchive.unc.edu\/index.php?rest_route=\/wp\/v2\/posts\/8758","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/collegearchive.unc.edu\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/collegearchive.unc.edu\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/collegearchive.unc.edu\/index.php?rest_route=\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"https:\/\/collegearchive.unc.edu\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=8758"}],"version-history":[{"count":2,"href":"https:\/\/collegearchive.unc.edu\/index.php?rest_route=\/wp\/v2\/posts\/8758\/revisions"}],"predecessor-version":[{"id":46873,"href":"https:\/\/collegearchive.unc.edu\/index.php?rest_route=\/wp\/v2\/posts\/8758\/revisions\/46873"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/collegearchive.unc.edu\/index.php?rest_route=\/wp\/v2\/media\/8761"}],"wp:attachment":[{"href":"https:\/\/collegearchive.unc.edu\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=8758"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/collegearchive.unc.edu\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=8758"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/collegearchive.unc.edu\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=8758"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}