Formation of fluorescence reliefs photocontrolled by collective mass migration

Exploiting Light Interferences to Generate Micrometer‐High Superstructures from Monomeric Azo Materials with Extensive Orientational Mobility

“…Synthesis of 4‐[4′[bis(4′‐tertbutylbiphenyl‐4‐yl)amino]phenylazo]benzoate ( azoCO 2 Me ) (adapted procedure from previously reported synthesis [ 24 ] ): To a solution of bis(4′‐ tert ‐butylbiphenyl‐4‐yl)‐4‐aminophenylamine (1.00 g, 1.91 mmol) in acetic acid (35 mL) in a round‐bottomed flask equipped with a magnetic stirrer was added 4‐nitrosobenzoate (0.30 g, 1.84 mmol) at ambient temperature. Once the addition was complete, the solution was stirred for 48 h in the dark at ambient temperature.…”

Design of Collective Motions from Synthetic Molecular Switches, Rotors, and Motors

“…SRG can also be used to pattern fluorescent substrate: − Ishow et al used an azotriarylamine derivative (Figure a) to form a 2D array of fluorescing spots (Figure b) . Oh and coworkers reported the formation of SRG at the tip of an optical fiber for applications such as beam splitter or diffractive lens …”

Nanoparticle Organization through Photoinduced Bulk Mass Transfer

“…13−16 The underlying photomigration mechanisms, undoubtedly related to azo E−Z isomerization cycles, have been largely debated and tentatively explained for most of them as a result of pressure gradient force, 17−19 plasticity and viscosity changes, 20,21 or optical field gradient force. 22−24 Surprisingly, the remarkable photoinduced azo mass transport has barely been exploited to gradually displace and organize exogenous objects, although several groups have attempted to create emissive structures by moving covalently 25,26 or noncovalently attached luminophores. 27,28 The motion of external macro-objects, such as the rotation of a microscale glass nanorod 29,30 or translation of a 5 μm polystyrene (PS) particle 30 deposited on LC photochromic surfaces, has also been demonstrated upon illumination and ascribed to collective microscopic changes in the molecular geometry of the irradiated photochromes.…”

“…Such a behavior has already been encountered for crowded azo compounds and is likely to feature the collective molecular rearrangements due to steric constraints. 25 Photoinduced Nanoparticle Displacement. Given the higher mass transfer performances of the CarbX series and CarbCN especially, we exploited them to displace nanoparticles deposited on the surface on azo thin films.…”

“…In contrast with ordered crystalline-like systems, the highly efficient photoresponse of molecular materials benefits from the presence of bulky peripheral groups creating large free volume around the azo units, so that the space-demanding E–Z photoisomerization can occur . In the same way as azo polymer or LCP materials, azo molecular thin films can undergo dramatic deformation into sinusoidal surface relief gratings (SRGs) upon interferential illumination. − The underlying photomigration mechanisms, undoubtedly related to azo E–Z isomerization cycles, have been largely debated and tentatively explained for most of them as a result of pressure gradient force, − plasticity and viscosity changes, , or optical field gradient force. − Surprisingly, the remarkable photoinduced azo mass transport has barely been exploited to gradually displace and organize exogenous objects, although several groups have attempted to create emissive structures by moving covalently , or noncovalently attached luminophores. , The motion of external macro-objects, such as the rotation of a microscale glass nanorod , or translation of a 5 μm polystyrene (PS) particle deposited on LC photochromic surfaces, has also been demonstrated upon illumination and ascribed to collective microscopic changes in the molecular geometry of the irradiated photochromes. These systems however required the films to have large thicknesses (>50 μm) to stand to the weight of the micrometric objects and induce large motion amplitude.…”