Photoinduced Curling of Organic Molecular Crystal Nanowires

Abstract

Molecular crystal nanowires composed of an anthracene‐9‐(1,3‐butadiene) derivative exhibit a rapid transition from straight to highly coiled structures when exposed to a pulse of visible light. The curling does not depend on the direction of light illumination and occurs for nanowires composed of either the E or Z isomer. The shape change is driven by an E⇄Z photoisomerization reaction that generates a mixture of isomers within a single nanowire.

Switchable molecule-based materials for micro- and nanoscale actuating applications: Achievements and prospects

“…1 s and this motion continued even after switching off the light (Fig. 13 left) [98]. While the mechanism of this phenomenon is not perfectly clear the molecules undergo a partially complete photoisomerization, which must be the key driving factor of the observed motion.…”

“…This device, using palindromic [3]rotaxane molecules, allowed improvement of both the static (force and stroke) as well as the dynamic response of the system -paving the way for true MEMS operation. [98], with permission of the copyright holders). Photoinduced twisting of 9-anthracenecarboxylic acid before (a), immediately after (b) and 9 min after (c) UV irradiation.…”

Controlling Motion at the Nanoscale: Rise of the Molecular Machines

“…Cleverly engineered, such actuating crystals can perform work pushing or lifting objects many times their weight, 214 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 irreversible twisting of crystalline microribbons. 219,220 The curling and twisting motion may be attributed to strain between spatially distinct reactant and product domains as a result of differential absorption by different regions of the crystal or intrinsic solid-state reaction kinetics. 221 concluding that isomerization can still occur inside the crystal.…”

Crystal structure of the meta-stable intermediate in the photomechanical, crystal-to-crystal reaction of 9-tert-butyl anthracene ester

“…These materials take advantage of photochemical reactions to convert photon energy directly into mechanical work. [6][7][8][9][10][11][12][13][14][15][16][17][18] In most cases, these dramatic shape changes rely on the formation of a bimorph structure, where interfacial stress between spatially distinct regions of reactant and photoproduct drives the deformation. 1 For example, the cis-trans photoisomerization of azobenzene molecules embedded in liquid crystal polymers can drive dramatic lightinduced bending and curling.…”