{"id":3159,"date":"2011-01-21T13:50:06","date_gmt":"2011-01-21T11:50:06","guid":{"rendered":"http:\/\/localhost\/azgad\/wordpress\/?p=3159"},"modified":"2011-01-21T14:03:24","modified_gmt":"2011-01-21T12:03:24","slug":"making-light-work-of-artificial-muscles","status":"publish","type":"post","link":"https:\/\/azgad.com\/?p=3159","title":{"rendered":"Making light work of artificial muscles"},"content":{"rendered":"

.
\nA new form of self-assembling polymer film that bends and stretches when
\nhit by light is pointing the way to a new family of functional materials. This
\nflexing film is the first material to have been made by coaxing complex
\nmolecules to form large-scale, highly ordered three dimensional arrays\u2014a
\ndiscovery that could change the way that many active material are made,
\nfrom artificial muscles to solar cells.
\n.
\nNobuhiko Hosono, Takuzo Aida and colleagues at RIKEN Advanced Science
\nInstitute in Wako and The University of Tokyo developed the self-assembly
\nprotocol. The researchers found that brush-shaped polymers would form
\nan orderly film when hot-pressed between two sheets of Teflon1.
\n.
\nThey made their discovery while studying a polymer in which each side chain,
\nor bristle, of the brush structure incorporates light-responsive azobenzenes\u2014two
\nbenzene rings separated by a pair of nitrogen atoms. When hit by UV light, the
\nbond between the nitrogens rearranges, contracting the side chain.
\n.
\nThe researchers used this photoisomerization behavior to confirm the remarkable
\nlong-range order of the polymer structure. Because the side chains were all
\naligned, when those at the surface were hit by light they curled up in concert,
\nbending the film. A second beam of light at a different wavelength reversed
\nthe isomerization process, and the film relaxed back to its original shape.
\n.
\nThe trick to making the material is to heat it between two sheets of Teflon that
\nhave been drawn tight in one direction, says Hosono. This tension orients the
\nTeflon sheets\u2019 internal structure along a single axis, which acts as a template
\nfor the molten polymer brushes sandwiched in between. The side chains of
\nthe polymer brush align with the Teflon, pulling each brush upright. As each
\npolymer brush aligns in the same way, it forms a repeating three-dimensional
\narray (Fig. 1).
\n.
\n\"\"<\/a>.
\n.
\n.
\nFigure<\/strong> 1: The light-responsive film is made up of polymer brushes (right
\nthat have self-assembled into a two-layer, three-dimensional array (left).
\n.
\nHosono, Aida and colleagues expect the technique to work for other polymer brushes
\nwith similar side chains. To improve the artificial muscle-like behavior of their polymer
\nfilm, Hosono says the team will try cross-linking the polymer side chains. This will
\nprevent the molecular structure from becoming disordered as the polymer repeatedly
\ncurls and relaxes over many cycles, giving the muscle a longer lifetime.
\n.
\nThe team is already assessing other potential applications. The wide-area
\nthree-dimensional molecular ordering of the polymer brush has great potential
\nfor building electronic devices, says Hosono. \u201cWe now have designed a new
\ntype of polymer brush for development of highly efficient thin-layer organic
\nsolar cells.\u201d
\n.<\/p>\n","protected":false},"excerpt":{"rendered":"

. A new form of self-assembling polymer film that bends and stretches when hit by light is pointing the way to a new family of functional materials. This flexing film is the first material to have been made by coaxing complex molecules to form large-scale, highly ordered three dimensional arrays\u2014a discovery that could change the … <\/p>\n

\u05d4\u05de\u05e9\u05d9\u05db\u05d5 \u05d1\u05e7\u05e8\u05d9\u05d0\u05d4<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[10],"tags":[513,186],"class_list":["post-3159","post","type-post","status-publish","format-standard","hentry","category-10","tag-513","tag-186","nodate","item-wrap"],"_links":{"self":[{"href":"https:\/\/azgad.com\/index.php?rest_route=\/wp\/v2\/posts\/3159","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/azgad.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/azgad.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/azgad.com\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/azgad.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=3159"}],"version-history":[{"count":12,"href":"https:\/\/azgad.com\/index.php?rest_route=\/wp\/v2\/posts\/3159\/revisions"}],"predecessor-version":[{"id":3176,"href":"https:\/\/azgad.com\/index.php?rest_route=\/wp\/v2\/posts\/3159\/revisions\/3176"}],"wp:attachment":[{"href":"https:\/\/azgad.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=3159"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/azgad.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=3159"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/azgad.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=3159"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}