Yifei Pan1, Huan Zhang1, Piaoxue Xu1, Yancong Tian2, Chenxu Wang2, Shishuai Xiang1, Roman Boulatov2, Wengui Weng1. 1. Department of Chemistry, College of Chemistry and Chemical Engineering, Xiamen University, 422 South Siming Road, Xiamen, Fujian, 361005, P. R. China. 2. Department of Chemistry, University of Liverpool and Donnan Lab, G31, Crown St., Liverpool, L69 7ZD, UK.
Abstract
We demonstrate an intermolecular reaction cascade to control the force which triggers crosslinking of a mechanochromic polymer of spirothiopyran (STP). Mechanochromism arises from rapid reversible force-sensitive isomerization of STP to a merocyanine, which reacts rapidly with activated C=C bonds. The concentration of such bonds, and hence the crosslinking rate, is controlled by force-dependent dissociation of a Diels-Alder adduct of anthracene and maleimide. Because the adduct requires ca. 1 nN higher force to dissociate at the same rate as that of STP isomerization, the cascade limits crosslinking to overstressed regions of the material, which are at the highest rate of material damage. Using comb polymers decreased the minimum concentration of mechanophores required to crosslinking by about 100-fold compared to previous examples of load-strengthening materials. The approach described has potential for controlling a broad range of reaction sequences triggered by mechanical load.
We demonstrate an intermolecular reaction cascade to control the force which triggers crosslinking of a mechanochromic polymer of pan class="Chemical">spirothiopyran (STP). Mechanochromism arises from rapid reversible force-sensitive isomerization of STP to a merocyanine, which reacts rapidly with activated C=C bonds. The concentration of such bonds, and hence the crosslinking rate, is controlled by force-dependent dissociation of a Diels-Alder adduct of anthracene and maleimide. Because the adduct requires ca. 1 nN higher force to dissociate at the same rate as that of STP isomerization, the cascade limits crosslinking to overstressed regions of the material, which are at the highest rate of material damage. Using comb polymers decreased the minimum concentration of mechanophores required to crosslinking by about 100-fold compared to previous examples of load-strengthening materials. The approach described has potential for controlling a broad range of reaction sequences triggered by mechanical load.
Authors: Zachary S Kean; Gregory R Gossweiler; Tatiana B Kouznetsova; Gihan B Hewage; Stephen L Craig Journal: Chem Commun (Camb) Date: 2015-06-04 Impact factor: 6.222
Authors: Ashley L Black Ramirez; Zachary S Kean; Joshua A Orlicki; Mangesh Champhekar; Sarah M Elsakr; Wendy E Krause; Stephen L Craig Journal: Nat Chem Date: 2013-08-04 Impact factor: 24.427
Authors: Maxwell J Robb; Tae Ann Kim; Abigail J Halmes; Scott R White; Nancy R Sottos; Jeffrey S Moore Journal: J Am Chem Soc Date: 2016-09-12 Impact factor: 15.419
Authors: Zachary S Kean; Zhenbin Niu; Gihan B Hewage; Arnold L Rheingold; Stephen L Craig Journal: J Am Chem Soc Date: 2013-08-27 Impact factor: 15.419