Combined light- and heat-induced shape memory behavior of anthracene-based epoxy elastomers

Abstract

The development of multi-stimuli-responsive shape memory polymers has received increasing attention because of its scientific and technological significance. In this work, epoxy elastomers with reversible crosslinks are synthesized by polymerizing an anthracene-functionalized epoxy monomer, a diepoxy comonomer, and a dicarboxylic acid curing agent. The synthesized elastomers exhibit active responses to both light and heat enabled by the incorporated anthracene groups. When exposed to 365 nm UV light, additional crosslinking points are created by the photo-induced dimerization of pendant anthracene groups. The formation of the crosslinking points increases modulus and glass transition temperature of the elastomers, allowing for the fixation of a temporary shape at room temperature. The temporary shape remains stable until an external heat stimulus is applied to trigger the scission of the dimerized anthracene, which reduces the modulus and glass transition temperature and allows the elastomers to recover their original shapes. The effects of external stimuli on the thermal and dynamic mechanical properties of the elastomers are investigated experimentally and are correlated with molecular dynamics simulations that reveal the changes of structure and dynamics of the anthracene molecules and flexible chains.

Photo‐Controlled [4+4] Cycloaddition of Anthryl‐Polymer Systems: A Versatile Approach to Fabricate Functional Materials

“…[55] Anthracene-containing epoxy elastomers (8). [56] Poly(aryl ether ketone) post-modified with anthracene side groups (9). [57] Liquid crystal polymer system that contains anthryl pendant groups (10).…”

“…[50] Polymers based on methylene diphenyl diisocyanate, polycaprolactone diol and BHEAA ( 7 ) [55] . Anthracene‐containing epoxy elastomers ( 8 ) [56] . Poly(aryl ether ketone) post‐modified with anthracene side groups ( 9 ) [57] .…”

Smart Shape Memory Polyurethane with Photochromism and Mechanochromism Properties

“…[1][2][3][4][5][6][7][8][9] There are several types of SMP materials, and they can be divided into thermally, electrically, photo, magnetically, and chemically actuated SMPs. [10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] At present, most SMPs are thermally actuated, and they are heated to a shape memory transition temperature T trans (T trans is the shape memory transition temperature, which is the glass transition temperature or melting transition temperature). Then, the temporary shape of the SMP is fixed by maintaining the external force and reducing the temperature to below T trans .…”

Cyclic and linear dithienyl-anthryl vinylenes: synthesis, X-ray crystallography, spectroscopic properties, and photoinduced mechanical motions

“…35,36 Photodimerization of anthracenes was also observed in polymers, producing photo-cross-linkable and healable polymers. [37][38][39][40] On the other hand, photoresponsive crystals [41][42][43][44][45][46] and polymers [47][48][49][50][51][52] have been of great interest because they can transduce light energy into mechanical motions toward actuators with a desirable size from the molecular to macroscopic scale. We considered that introduction of bulky groups on the 9,10-positions of anthracene suppresses photodimerization of anthracenes, thus inducing mechanical motions of anthracenecontaining molecules by facile light-controls, such as light on/off, in single crystals and polymer films.…”