{"499581":{"#nid":"499581","#data":{"type":"event","title":"Mechanoresponsive molecules as force sensors and self-healing materials","body":[{"value":"\u003Cp\u003EMolecules that show a\u0026nbsp;defined response to mechanical force (mechanophores) can be used as the\u0026nbsp;building blocks of mechanoreponsive materials. For example, the\u0026nbsp;mechanical activation of a latent catalyst\u0026nbsp;can generate fluorophores that allow the early detection of bond rupture\u0026nbsp;processes. The catalyst\u0026nbsp;might also start a chain reaction that initiates the\u0026nbsp;reformation of bonds in the material, thus introducing self-healing properties. \u0026nbsp;I will give an introduction to mechanochemistry experiments and compare them to\u0026nbsp;force experiments in biology. In a first study, theoretical calculations\u0026nbsp;of the load rate dependence of the\u0026nbsp;mechanical activation of a latent catalyst\u0026nbsp;(N-heterocyclic\u0026nbsp;carbene) reveal kinetic effects that explain the diverging\u0026nbsp;results from\u0026nbsp;AFM\u0026nbsp;and ultrasound experiments.\u0026nbsp;A\u0026nbsp;second application targets the formation of a triazole unit in a cycloaddition\u0026nbsp;reaction between azides\u0026nbsp;and alkynes, which is a widely used tool in materials\u0026nbsp;chemistry, where it allows the functionalization of polymers and surfaces as\u0026nbsp;well as the synthesis\u0026nbsp;of macromolecular structures. We have investigated theoretically\u0026nbsp;the mechanically induced reversion of this reaction (cycloreversion), which\u0026nbsp;would\u0026nbsp;allow for the straightforward design of mechanoresponsive materials. We\u0026nbsp;show that cycloreversion is principally possible and that the pulling geometry\u0026nbsp;is the most important parameter. This geometry effect has also been observed in\u0026nbsp;biological systems\u0026nbsp;e.g.\u0026nbsp;for the\u0026nbsp;mechanical separation of DNA or\u0026nbsp;b-strands\u0026nbsp;in proteins. It appears to be a general principle that also applies to the\u0026nbsp;mechanical rupture of covalent bonds in ring structures.\u003C\/p\u003E","summary":null,"format":"limited_html"}],"field_subtitle":"","field_summary":"","field_summary_sentence":[{"value":"Mechanoresponsive molecules as force sensors and self-healing materials"}],"uid":"27664","created_gmt":"2016-02-12 11:53:20","changed_gmt":"2017-04-13 21:16:40","author":"Alison Morain","boilerplate_text":"","field_publication":"","field_article_url":"","field_event_time":{"event_time_start":"2016-02-16T14:00:00-05:00","event_time_end":"2016-02-16T15:00:00-05:00","event_time_end_last":"2016-02-16T15:00:00-05:00","gmt_time_start":"2016-02-16 19:00:00","gmt_time_end":"2016-02-16 20:00:00","gmt_time_end_last":"2016-02-16 20:00:00","rrule":null,"timezone":"America\/New_York"},"extras":[],"hg_media":{"499031":{"id":"499031","type":"image","title":"Guenter","body":null,"created":"1455145200","gmt_created":"2016-02-10 23:00:00","changed":"1475895258","gmt_changed":"2016-10-08 02:54:18","alt":"Guenter","file":{"fid":"205885","name":"gunther.png","image_path":"\/sites\/default\/files\/images\/gunther_0.png","image_full_path":"http:\/\/www.tlwarc.hg.gatech.edu\/\/sites\/default\/files\/images\/gunther_0.png","mime":"image\/png","size":436577,"path_740":"http:\/\/www.tlwarc.hg.gatech.edu\/sites\/default\/files\/styles\/740xx_scale\/public\/images\/gunther_0.png?itok=KrZRvLdm"}}},"media_ids":["499031"],"groups":[{"id":"126011","name":"School of Physics"}],"categories":[],"keywords":[{"id":"166937","name":"School of Physics"},{"id":"166896","name":"seminar"}],"core_research_areas":[],"news_room_topics":[],"event_categories":[{"id":"1795","name":"Seminar\/Lecture\/Colloquium"}],"invited_audience":[{"id":"78751","name":"Undergraduate students"},{"id":"78761","name":"Faculty\/Staff"},{"id":"174045","name":"Graduate students"}],"affiliations":[],"classification":[],"areas_of_expertise":[],"news_and_recent_appearances":[],"phone":[],"contact":[{"value":"\u003Cp\u003E\u003Ca href=\u0022mailto:amorain@gatech.edu\u0022\u003Eamorain@gatech.edu\u003C\/a\u003E\u003C\/p\u003E","format":"limited_html"}],"email":[],"slides":[],"orientation":[],"userdata":""}}}