Nanoparticle Organization through Photoinduced Bulk Mass Transfer

Snell, Kristen E.; Stéphant, Nicolas; Pansu, Robert; Audibert, Jean-Frédéric; Lagugné‐Labarthet, François; Ishow, Eléna

doi:10.1021/la404988d

Cited by 18 publications

(28 citation statements)

References 49 publications

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“…To extract the rate constants (k i ) associated with the dynamics of the birefringence measurements during both the orientation and relaxation processes, biexponential fitting laws were used as already reported for the photochromic studies in thin films. 35,49,52 The orientation processes are described by eq 2 while the relaxation is described by eq 3.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Enhanced Rates of Photoinduced Molecular Orientation in a Series of Molecular Glassy Thin Films

et al. 2015

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Photoinduced orientation in a series of molecular glasses made of small push-pull azo derivatives is dynamically investigated for the first time. Birefringence measurements at 632.8 nm are conducted with a temporal resolution of 100 ms to probe the fast rate of the azo orientation induced under polarized light and its temporal stability over several consecutive cycles. To better evaluate the influence of the azo chemical substituents and their electronic properties on the orientation of the whole molecule, a series of push-pull azo derivatives involving a triphenylaminoazo core substituted with distinct electron-withdrawing moieties is studied. All resulting thin films are probed using polarization modulation infrared spectroscopy that yields dynamical linear dichroism measurements during a cycle of orientation followed by relaxation. We show here in particular that the orientation rates of small molecule-based azo materials are systematically increased up to 7-fold compared to those of a reference polymer counterpart. For specific compounds, the percentage of remnant orientation is also higher, which makes these materials of great interest and promising alternatives to azobenzene-containing polymers for a variety of applications requiring a fast response and absolute control over the molecular weight.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Enhanced Rates of Photoinduced Molecular Orientation in a Series of Molecular Glassy Thin Films

et al. 2015

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“…To contextualize this observation, UV–vis and Raman spectroscopy measurements on pDR1a have shown that the fraction of cis isomers in the photostationary state decreases when applying an increasing hydrostatic pressure but that some photoisomerization remains possible even at applied pressures as high as 1 GPa . This capability of macroscopic material transport can be used to move passive objects, as was shown for polystyrene nanoparticles on the surface of an azobenzene‐containing glassy film …”

Section: All‐optical Mass Transport Of Materialsmentioning

confidence: 91%

Taming Macromolecules with Light: Lessons Learned from Vibrational Spectroscopy

Vapaavuori

Bazuin

Pellerin

2017

Macromol. Rapid Commun.

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application of vibrational spectroscopy to rotaxane-based molecular machines, [11] molecular motors, [12] and molecule-based electronics, such as molecular electronic switches, [13] are highly recommended.In this feature article, we will focus on one of the most commonly used photoswitches, both for materials engineering and biological applications, namely, azobenzene. [14] This motif is known to change its geometry upon illumination with ultraviolet or visible light, in a socalled photoisomerization reaction from the thermodynamically stable trans conformation to the bent cis conformation (Figure 1a). [15,16] This reaction can be used to both decrease and destroy existing order in materials, as in the cases of photoinduced unfolding of azobenzenecrosslinked alpha-helical peptides, [17] photo induced nematic-isotropic phase transitions [18] and isothermal solid-toliquid transitions, [19] or, on the contrary, to induce order and anisotropy in initially isotropic or less ordered materials, such as in photoinduced birefringence, photoinduced chirality, alloptical poling, and surface relief grating (SRG) formation. [2,20,21] The photoisomerization of individual azobenzene moieties is known to occur in the picosecond timescale and results in changes in its molecular dimensions and properties, such as its dipole moment, solubility and UV-vis absorption. [15] Apolar azobenzene molecules typically have well isolated cis and trans absorption bands along with long thermal cis lifetimes. They are therefore suitable for optical switching applications where two "stable" long-lived states are required. By contrast, functionalizing azobenzene molecules with electron donating and electron withdrawing substituents (or push-pull substitution) alters their photochemistry, typically leading to an overlap of cis and trans absorption bands and thus to quasi-continuous photoswitching between the trans and the cis geometrical isomers. [15,16] Examples of drastic changes in material systems resulting from bistable photoswitching between trans and long-lived cis isomers are illustrated in Figure 1b-d and include photoswitching of the tilt of liquid crystals by an azopolymer command layer, [22] the light-powered contraction of a helical ribbon of a liquid crystalline azopolymer, mimicking plant tendrils, [23] and the photoinduced decrease in helix content of a peptide cross-linked by an azobenzene. [17] Demonstrations of the use of continuous azobenzene photoswitching between the two geometrical isomers, shown in Figure 1e

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“…A polymer film containing azobenzene, which gives a liquid‐crystalline structure and dichroism to the polymer, showed photoinduced bending perpendicular to the direction of polarization . Another representative example is the system using polarized light with an interference fringe to form a grating relief on the surface of azobenzene polymers . These deformations of polymers containing azobenzene were caused by trans – cis isomerization, which changes the degree of orientation in the liquid‐crystalline structure.…”

Section: Figurementioning

confidence: 99%

“…[19] Another representative example is the system using polarized light with an interference fringe to form ag rating relief on the surface of azobenzene polymers. [20,21] These deformationso fp olymers containing azobenzene werec aused by trans-cis isomerization, which changes the degree of orientation in the liquid-crystalline structure.Amphiphilic diarylethene 1 forms micrometer-sized spherical aggregates in water and exhibited reversible morphological changes between sphere and nanofiber phases upon irradiation with UV and visible light,a sr eported in our previous work (Figure 1). [22] The photoinduced morphological change was causedb yp hotoisomerization of the diarylethenem olecules within the supramolecular architectures.…”

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Anisotropic Diffusion of Microbeads Surrounded by an Anisotropically Elongated Supramolecular Diarylethene Architecture under Linearly Polarized Light

2017

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Upon irradiation of an amphiphilic diarylethene derivative (which shows a photoinduced morphological transformation in water between sphere and fiber states) with linearly polarized light, elongation of the fiber in the direction of polarization was observed in TEM images. The diffusive motion was suppressed in the direction perpendicular to that of the generated fiber, as revealed by means of trajectory tracking of added polystyrene (PS) beads. When unpolarized UV light was used, the TEM image showed no anisotropic features and the diffusion of PS beads was isotropic. These results provide a means for anisotropic photocontrol of the morphology of supramolecular architectures.

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Nanoparticle Organization through Photoinduced Bulk Mass Transfer

Cited by 18 publications

References 49 publications

Enhanced Rates of Photoinduced Molecular Orientation in a Series of Molecular Glassy Thin Films

Enhanced Rates of Photoinduced Molecular Orientation in a Series of Molecular Glassy Thin Films

Taming Macromolecules with Light: Lessons Learned from Vibrational Spectroscopy

Anisotropic Diffusion of Microbeads Surrounded by an Anisotropically Elongated Supramolecular Diarylethene Architecture under Linearly Polarized Light

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