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Saphiannikova M, Toshchevikov V, Tverdokhleb N. Optical deformations of azobenzene polymers: orientation approach vs. other concepts. SOFT MATTER 2024; 20:2688-2710. [PMID: 38465418 DOI: 10.1039/d4sm00104d] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/12/2024]
Abstract
It has been 30 years since the discovery of surface restructuring in thin azopolymer films by two independent research groups. A wide variety of topographical structures have been created by the application of two-/four-beam interference patterns, space light modulators and even helical beams. There are a number of comprehensive reviews which describe in detail the advances in superficial photopatterning of azopolymer films and macroscopic deformations of azonetworks. The theoretical approaches are only briefly touched on in these reviews and often are accompanied by the remark that the phenomenon is far from being understood. In this review, we would like to present the polymer theoretist's point of view on this intriguing problem. We begin by describing a multitude of theoretical approaches and commenting on the pluses and drawbacks of each. Importantly, we show that in most cases the presence of an azopolymer matrix is either ignored or limited to a specific class of azopolymers (liquid-crystalline or elastomeric). We then move to early orientation approaches based on the hypothesis that reorientation of azo-chromophores by modulated polarized light is the sole cause of superficial patterning. At the end of the review a modern orientation approach, as proposed by our own group, is presented. This approach has high predictive power because it can explain a large pool of experimental data for different classes of azopolymers including glassy and liquid-crystalline materials. This is made possible by taking into account both the light-induced orientation process and the change of anisotropic interactions between the chromophores upon their isomerization. Last but not least, this is the only approach that provides an estimate of the light-induced stress large enough to cause plastic deformations of glassy azopolymers. Recent finite element modeling results show remarkable similarity to real patterns and even time-dependent data are well explained. With this, we claim that the puzzle is finally understood and the orientation approach is ready for its implementation for major azopolymer classes.
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Affiliation(s)
- Marina Saphiannikova
- Institute Theory of Polymers, Leibniz Institute of Polymer Research Dresden, 01069 Dresden, Germany.
| | - Vladimir Toshchevikov
- Institute of Macromolecular Compounds, Russian Academy of Sciences, 199004 Saint Petersburg, Russia
| | - Nina Tverdokhleb
- Institute Theory of Polymers, Leibniz Institute of Polymer Research Dresden, 01069 Dresden, Germany.
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2
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Nazarova D, Nedelchev L, Berberova-Buhova N, Mateev G. Nanocomposite Photoanisotropic Materials for Applications in Polarization Holography and Photonics. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2946. [PMID: 37999300 PMCID: PMC10674406 DOI: 10.3390/nano13222946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 10/27/2023] [Accepted: 11/03/2023] [Indexed: 11/25/2023]
Abstract
Photoanisotropic materials, in particular azodyes and azopolymers, have attracted significant research interest in the last decades. This is due to their applications in polarization holography and 4G optics, enabling polarization-selective diffractive optical elements with unique properties, including circular polarization beam-splitters, polarization-selective bifocal lenses, and many others. Numerous methods have been applied to increase the photoinduced birefringence of these materials, and as a result, to obtain polarization holographic elements with a high diffraction efficiency. Recently, a new approach has emerged that has been extensively studied by many research groups, namely doping azobenzene-containing materials with nanoparticles with various compositions, sizes, and morphologies. The resulting nanocomposites have shown significant enhancement in their photoanisotropic response, including increased photoinduced birefringence, leading to a higher diffraction efficiency and a larger surface relief modulation in the case of polarization holographic recordings. This review aims to cover the most important achievements in this new but fast-growing field of research and to present an extensive comparative analysis of the result, reported by many research groups during the last two decades. Different hypotheses to explain the mechanism of photoanisotropy enhancement in these nanocomposites are also discussed. Finally, we present our vision for the future development of this scientific field and outline its potential applications in advanced photonics technologies.
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Affiliation(s)
- Dimana Nazarova
- Institute of Optical Materials and Technologies, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria; (D.N.); (N.B.-B.); (G.M.)
- Department of Physics, University of Chemical Technology and Metallurgy, 1756 Sofia, Bulgaria
| | - Lian Nedelchev
- Institute of Optical Materials and Technologies, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria; (D.N.); (N.B.-B.); (G.M.)
- Department of Physics, University of Chemical Technology and Metallurgy, 1756 Sofia, Bulgaria
| | - Nataliya Berberova-Buhova
- Institute of Optical Materials and Technologies, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria; (D.N.); (N.B.-B.); (G.M.)
- Department of Physics, University of Chemical Technology and Metallurgy, 1756 Sofia, Bulgaria
| | - Georgi Mateev
- Institute of Optical Materials and Technologies, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria; (D.N.); (N.B.-B.); (G.M.)
- Department of Physics, University of Chemical Technology and Metallurgy, 1756 Sofia, Bulgaria
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Urban D, Marcucci N, Wölfle CH, Torgersen J, Hjelme DR, Descrovi E. Polarization-driven reversible actuation in a photo-responsive polymer composite. Nat Commun 2023; 14:6843. [PMID: 37891157 PMCID: PMC10611746 DOI: 10.1038/s41467-023-42590-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Accepted: 10/16/2023] [Indexed: 10/29/2023] Open
Abstract
Light-responsive polymers and especially amorphous azopolymers with intrinsic anisotropic and polarization-dependent deformation photo-response hold great promises for remotely controlled, tunable devices. However, dynamic control requires reversibility characteristics far beyond what is currently obtainable via plastic deformation of such polymers. Here, we embed azopolymer microparticles in a rubbery elastic matrix at high density. In the resulting composite, cumulative deformations are replaced by reversible shape switching - with two reversible degrees of freedom defined uniquely by the writing beam polarization. We quantify the locally induced strains, including small creeping losses, directly by means of a deformation tracking algorithm acting on microscope images of planar substrates. Further, we introduce free-standing 3D actuators able to smoothly undergo multiple configurational changes, including twisting, roll-in, grabbing-like actuation, and even continuous, pivot-less shape rotation, all dictated by a single wavelength laser beam with controlled polarization.
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Affiliation(s)
- David Urban
- Department of Electronic Systems, Norwegian University of Science and Technology, O.S. Bragstads plass 2b, 7034, Trondheim, Norway
- Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Torino, Italy
| | - Niccolò Marcucci
- Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Torino, Italy
| | - Christoph Hubertus Wölfle
- Institute of Materials Science, Department of Materials Engineering, TUM School of Engineering and Design, Technical University of Munich, Boltzmannstraße 15, 85748, Garching, Germany
| | - Jan Torgersen
- Institute of Materials Science, Department of Materials Engineering, TUM School of Engineering and Design, Technical University of Munich, Boltzmannstraße 15, 85748, Garching, Germany
| | - Dag Roar Hjelme
- Department of Electronic Systems, Norwegian University of Science and Technology, O.S. Bragstads plass 2b, 7034, Trondheim, Norway
| | - Emiliano Descrovi
- Dipartimento di Scienza Applicata e Tecnologia, Politecnico di Torino, Corso Duca degli Abruzzi 24, 10129, Torino, Italy.
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Kaban B, Bagatur S, Soter M, Hillmer H, Fuhrmann-Lieker T. Reversible Photo-Induced Reshaping of Imprinted Microstructures Using a Low Molecular Azo Dye. Polymers (Basel) 2022; 14:586. [PMID: 35160576 PMCID: PMC8838706 DOI: 10.3390/polym14030586] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/20/2022] [Accepted: 01/28/2022] [Indexed: 02/05/2023] Open
Abstract
A blend of low molecular azo glass (AZOPD) and polystyrene (PS) were used for the systematic investigation of photo-induced stretching and recovery of nanoimprinted structures. For this purpose, light and heat was used as recovery stimuli. The AZOPD/PS microstructures, fabricated with thermal nanoimprint lithography (tNIL), comprises three different shapes (circles, crosses and squares) and various concentrations of AZOPD fractions. The results show a concentration-dependent reshaping. Particularly the sample with 43 w-% of the AZOPD fraction have shown the best controllable recovery for the used parameters. A possible explanation for shape recovery might be the stabilizing effect of the PS-matrix.
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Affiliation(s)
- Burhan Kaban
- Institute of Nanostructure Technologies and Analytics (INA) and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany; (B.K.); (M.S.); (H.H.)
| | - Sekvan Bagatur
- Physical Chemistry of Nanomaterials, Institute of Chemistry and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany;
| | - Marcus Soter
- Institute of Nanostructure Technologies and Analytics (INA) and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany; (B.K.); (M.S.); (H.H.)
| | - Hartmut Hillmer
- Institute of Nanostructure Technologies and Analytics (INA) and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany; (B.K.); (M.S.); (H.H.)
| | - Thomas Fuhrmann-Lieker
- Physical Chemistry of Nanomaterials, Institute of Chemistry and Center for Interdisciplinary Nanostructure Science and Technology (CINSaT), University of Kassel, Heinrich-Plett-Straße 40, 34132 Kassel, Germany;
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Koch M, Saphiannikova M, Guskova O. Cyclic Photoisomerization of Azobenzene in Atomistic Simulations: Modeling the Effect of Light on Columnar Aggregates of Azo Stars. Molecules 2021; 26:7674. [PMID: 34946756 PMCID: PMC8709326 DOI: 10.3390/molecules26247674] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Revised: 12/14/2021] [Accepted: 12/15/2021] [Indexed: 12/02/2022] Open
Abstract
This computational study investigates the influence of light on supramolecular aggregates of three-arm azobenzene stars. Every star contains three azobenzene (azo) moieties, each able to undergo reversible photoisomerization. In solution, the azo stars build column-shaped supramolecular aggregates. Previous experimental works report severe morphological changes of these aggregates under UV-Vis light. However, the underlying molecular mechanisms are still debated. Here we aim to elucidate how light affects the structure and stability of the columnar stacks on the molecular scale. The system is investigated using fully atomistic molecular dynamics (MD) simulations. To implement the effects of light, we first developed a stochastic model of the cyclic photoisomerization of azobenzene. This model reproduces the collective photoisomerization kinetics of the azo stars in good agreement with theory and previous experiments. We then apply light of various intensities and wavelengths on an equilibrated columnar stack of azo stars in water. The simulations indicate that the aggregate does not break into separate fragments upon light irradiation. Instead, the stack develops defects in the form of molecular shifts and reorientations and, as a result, it eventually loses its columnar shape. The mechanism and driving forces behind this order-disorder structural transition are clarified based on the simulations. In the end, we provide a new interpretation of the experimentally observed morphological changes.
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Affiliation(s)
- Markus Koch
- Institute Theory of Polymers, Leibniz Institute of Polymer Research Dresden, Hohe Str. 6, 01069 Dresden, Germany;
| | - Marina Saphiannikova
- Institute Theory of Polymers, Leibniz Institute of Polymer Research Dresden, Hohe Str. 6, 01069 Dresden, Germany;
- Dresden Center for Computational Materials Science (DCMS), Technische Universität Dresden, 01062 Dresden, Germany
| | - Olga Guskova
- Institute Theory of Polymers, Leibniz Institute of Polymer Research Dresden, Hohe Str. 6, 01069 Dresden, Germany;
- Dresden Center for Computational Materials Science (DCMS), Technische Universität Dresden, 01062 Dresden, Germany
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7
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Bagatur S, Schlesag M, Fuhrmann-Lieker T. Polarization Dependent Photoinduced Supramolecular Chirality in High-Performance Azo Materials. Molecules 2021; 26:2842. [PMID: 34064773 PMCID: PMC8150594 DOI: 10.3390/molecules26102842] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/26/2021] [Accepted: 05/04/2021] [Indexed: 11/26/2022] Open
Abstract
Here, we will show photo-induced supramolecular chirality in thin films of achiral amorphous polymers with azo groups in their side-chain. A matter of particular interest is the effect of various film thicknesses on azimuthal rotation and ellipticity of incident/transmitted polarized light. Furthermore, we investigated the temporal stability of inscribed chirality. By polarimetric measurements, we found out that the azimuthal rotation gets higher with layer thickness. In this scope, we were able to measure a very high azimuthal rotation of Δψ/d=112.5∘/μm. The inscribed chirality was stable for several days. Furthermore, we investigated the time-resolved behavior of incident and transmitted polarization ellipticities for various thicknesses. The time dependency may be explained by a two-step process: (1) fast trans-cis-isomerization resulting in photo-orientation and (2) slow photo-induced mass flow.
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Affiliation(s)
| | | | - Thomas Fuhrmann-Lieker
- Physical Chemistry of Nanomaterials, Institute of Chemistry and Center for Interdisciplinary Nanostructure Science and Technology, University of Kassel, Heinrich-Plett Str. 40, 34132 Kassel, Germany; (S.B.); (M.S.)
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Mitus AC, Saphiannikova M, Radosz W, Toshchevikov V, Pawlik G. Modeling of Nonlinear Optical Phenomena in Host-Guest Systems Using Bond Fluctuation Monte Carlo Model: A Review. MATERIALS (BASEL, SWITZERLAND) 2021; 14:1454. [PMID: 33809785 PMCID: PMC8002275 DOI: 10.3390/ma14061454] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 03/05/2021] [Accepted: 03/08/2021] [Indexed: 12/14/2022]
Abstract
We review the results of Monte Carlo studies of chosen nonlinear optical effects in host-guest systems, using methods based on the bond-fluctuation model (BFM) for a polymer matrix. In particular, we simulate the inscription of various types of diffraction gratings in degenerate two wave mixing (DTWM) experiments (surface relief gratings (SRG), gratings in polymers doped with azo-dye molecules and gratings in biopolymers), poling effects (electric field poling of dipolar molecules and all-optical poling) and photomechanical effect. All these processes are characterized in terms of parameters measured in experiments, such as diffraction efficiency, nonlinear susceptibilities, density profiles or loading parameters. Local free volume in the BFM matrix, characterized by probabilistic distributions and correlation functions, displays a complex mosaic-like structure of scale-free clusters, which are thought to be responsible for heterogeneous dynamics of nonlinear optical processes. The photoinduced dynamics of single azopolymer chains, studied in two and three dimensions, displays complex sub-diffusive, diffusive and super-diffusive dynamical regimes. A directly related mathematical model of SRG inscription, based on the continuous time random walk (CTRW) formalism, is formulated and studied. Theoretical part of the review is devoted to the justification of the a priori assumptions made in the BFM modeling of photoinduced motion of the azo-polymer chains.
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Affiliation(s)
- Antoni C. Mitus
- Department of Theoretical Physics, Wroclaw University of Science and Technology, 50-370 Wroclaw, Poland; (A.C.M.); (W.R.)
| | - Marina Saphiannikova
- Leibniz-Institut für Polymerforschung Dresden e.V., Hohe Strasse 6, 01069 Dresden, Germany;
| | - Wojciech Radosz
- Department of Theoretical Physics, Wroclaw University of Science and Technology, 50-370 Wroclaw, Poland; (A.C.M.); (W.R.)
| | - Vladimir Toshchevikov
- Institute of Macromolecular Compounds, Russian Academy of Sciences, Bolshoi Prospect 31, 199004 Saint Petersburg, Russia;
| | - Grzegorz Pawlik
- Department of Theoretical Physics, Wroclaw University of Science and Technology, 50-370 Wroclaw, Poland; (A.C.M.); (W.R.)
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Huang H, Wang Z, Li X, Yang F, Su Y, Xu J, Wang X. Directional mass transfer of azo molecular glass microsphere induced by polarized light in aqueous immersion media. RSC Adv 2021; 11:15387-15399. [PMID: 35424066 PMCID: PMC8698237 DOI: 10.1039/d1ra01904j] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Accepted: 04/16/2021] [Indexed: 12/16/2022] Open
Abstract
Photoinduced mass transfer of azo polymer and azo molecular glass has been intensively investigated under various light irradiation conditions simply using air as the ambient environment. In this work, in order to understand the effects of the surrounding medium on the light-induced process, azo molecular glass microspheres adhered on a substrate were immersed in water and different aqueous solutions, and their mass transfer behavior was investigated by irradiation with linearly polarized light. The microspheres in the aqueous media showed significant deformation through directional mass transfer upon light irradiation and transformed into a series of shape-anisotropic particles as revealed by microscopic observations. Compared with their counterparts upon light irradiation in air, the particles immersed in the aqueous media exhibited larger elongation parallel to the substrate and higher shape anisotropy. Optical simulation showed that this was caused by the alteration of the direction of the electric vibration of the refracted light at the medium–microsphere interface, which controlled the mass transfer behavior. On the other hand, the viscosity of the aqueous media showed no effect on the mass transfer process induced by the irradiation. The photo-thermal effect on the mass transfer behavior was ruled out as the thermal dissipation through a liquid is much more efficient than that through air. On the basis of this, this methodology was also successfully employed in the photo-fabrication of anisotropic submicron-sized periodic structures in aqueous medium. These observations can supply deep understanding of this fascinating process induced by polarized light and extend the scope of its applications. Directional mass transfer of azo molecular glass microspheres is comprehensively investigated upon polarized light irradiation in various aqueous immersion media, and the key factors to influence mass transfer and shape deformation are elucidated.![]()
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Affiliation(s)
- Hao Huang
- Department of Chemical Engineering
- Laboratory of Advanced Materials (MOE)
- Tsinghua University
- Beijing 100084
- People's Republic of China
| | - Zenan Wang
- Department of Chemical Engineering
- Laboratory of Advanced Materials (MOE)
- Tsinghua University
- Beijing 100084
- People's Republic of China
| | - Xu Li
- Department of Chemical Engineering
- Laboratory of Advanced Materials (MOE)
- Tsinghua University
- Beijing 100084
- People's Republic of China
| | - Fan Yang
- Department of Physics
- State Key Laboratory of Low Dimensional Quantum Physics
- Tsinghua University
- Beijing 100084
- People's Republic of China
| | - Yechao Su
- Department of Chemical Engineering
- The State Key Lab of Chemical Engineering
- Tsinghua University
- Beijing 100084
- People's Republic of China
| | - Jianhong Xu
- Department of Chemical Engineering
- The State Key Lab of Chemical Engineering
- Tsinghua University
- Beijing 100084
- People's Republic of China
| | - Xiaogong Wang
- Department of Chemical Engineering
- Laboratory of Advanced Materials (MOE)
- Tsinghua University
- Beijing 100084
- People's Republic of China
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10
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Bobrovsky A, Mochalov K, Solovyeva D, Shibaev V, Cigl M, Hamplová VCBR, Bubnov A. Laser-induced formation of "craters" and "hills" in azobenzene-containing polymethacrylate films. SOFT MATTER 2020; 16:5398-5405. [PMID: 32452491 DOI: 10.1039/d0sm00601g] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Functional organic polymer materials with an ability to change their surface topography in response to external contactless stimuli, like light irradiation, have attracted considerable attention. This work is devoted to the study of contactless control of the surface topography and the formation of the surface features in the amorphousized and liquid crystalline films of two azobenzene-containing polymers. The investigated polymers are side-chain polymethacrylates containing azobenzene chromophores with two lateral methyl substituents in ortho-positions and differing in the length of flexible spacer with six and ten methylene units. Two lateral methyl substituents at the azobenzene chromophore ensure high photoresponses of these polymeric samples in the whole visible spectral range. Irradiation of the polymethacrylate films by focused polarized light of green (532 nm) and red (633 nm) lasers induces a specific photodeformation of the film surface. In the case of the green light formation of circular "craters" with anisotropic borders was found, whereas for the red light highly asymmetric "hills" were observed. The possible mechanisms of the surface topography formation and their features are discussed.
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Affiliation(s)
- Alexey Bobrovsky
- Faculty of Chemistry, Moscow State University, Leninskie gory, Moscow, 119991, Russia.
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Swan S, Egemole FO, Nguyen ST, Kim JH. Assembly of Short-Chain Amphiphilic Homopolymers into Well-Defined Particles. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:4548-4555. [PMID: 32248691 DOI: 10.1021/acs.langmuir.0c00073] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Linear homopolymers of norbornene (NBE) derivatives equipped with short-chain alcohol pendant groups were prepared by ring-opening metathesis polymerization (ROMP) and subsequently assembled into well-defined structures in alcohol solvents. The ratios of hydrophobic carbons and hydrophilic alcohol groups at the repeating monomeric unit in these short-chain amphiphilic polymers were found to play an important role in determining the size and distribution of the final globular structures. Unlike the assembly of other linear homo- and copolymers possessing long-chain amphiphilicity, NBE-based linear polymers were readily transformed into spherical particles with a layered conformation, whose sizes range from a few hundred nanometers to micrometers with narrow distributions, simply by controlling the concentration and molecular weights of the linear homopolymers without using any surfactants. In addition, the degree of the intermolecular forces with solvents (e.g., solvation) possessing different surface tensions and polarities highly affected the final diameter and distribution of the polymer particles, implying the importance of the selection of a proper solvent to regulate their structural features. As such, understanding the assembly of these types of short-chain homopolymers into uniform particles can allow for regulating the transformation of diverse linear amphiphilic polymers into precisely controlled structures for various applications.
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Affiliation(s)
- Stephanie Swan
- Department of Chemistry, Illinois State University, Normal, Illinois 61790-4160, United States
| | - Franklin O Egemole
- Department of Chemistry, Illinois State University, Normal, Illinois 61790-4160, United States
| | - SonBinh T Nguyen
- Department of Chemistry and the International Institute for Nanotechnology, Northwestern University, Evanston, Illinois 60208, United States
| | - Jun-Hyun Kim
- Department of Chemistry, Illinois State University, Normal, Illinois 61790-4160, United States
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12
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Yadav B, Domurath J, Saphiannikova M. Modeling of Stripe Patterns in Photosensitive Azopolymers. Polymers (Basel) 2020; 12:E735. [PMID: 32224848 PMCID: PMC7240688 DOI: 10.3390/polym12040735] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2020] [Revised: 03/20/2020] [Accepted: 03/21/2020] [Indexed: 01/29/2023] Open
Abstract
Placed at interfaces, azobenzene-containing materials show extraordinary phenomena when subjected to external light sources. Here we model the surface changes induced by one-dimensional Gaussian light fields in thin azopolymer films. Such fields can be produced in a quickly moving film irradiated with a strongly focused laser beam or illuminating the sample through a cylindrical lens. To explain the appearance of stripe patterns, we first calculate the unbalanced mechanical stresses induced by one-dimensional Gaussian fields in the interior of the film. In accordance with our orientation approach, the light-induced stress originates from the reorientation of azobenzenes that causes orientation of rigid backbone segments along the light polarization. The resulting volume forces have different signs and amplitude for light polarization directed perpendicular and parallel to the moving direction. Accordingly, the grooves are produced by the stretching forces and elongated protrusions by the compressive forces. Implementation into a viscoplastic model in a finite element software predicts a considerably weaker effect for the light polarized along the moving direction, in accordance with the experimental observations. The maximum value in the distribution of light-induced stresses becomes in this case very close to the yield stress which results in smaller surface deformations of the glassy azopolymer.
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Affiliation(s)
| | | | - Marina Saphiannikova
- Leibniz-Institut für Polymerforschung, Hohe Straße 6, 01069 Dresden, Germany; (B.Y.); (J.D.)
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13
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Cheng Q, Zhang Y, Luan T, Wang Z, Tang R, Xing P, Hao A. Hydrogels Self-Assembled from an Azobenzene Building Block: Stability toward UV Irradiation in the Gel and Thin-Film States. Chempluschem 2020; 84:328-332. [PMID: 31939216 DOI: 10.1002/cplu.201900042] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2019] [Revised: 02/27/2019] [Indexed: 10/27/2022]
Abstract
Azobenzene and its derivatives are widely used as photoresponsive units for the fabrication of photoresponsive smart materials. In this work, two azobenzene derivatives were designed and investigated as hydrogelators, namely N-4-azodiphenyl-maleimic acid (ADPMA) and N-4-azodiphenyl-succinic acid (ADPSA) bearing azobenzene and carboxylic acid segments. In the process of deprotonation/protonation of the carboxylic acids by pH variation, the self-assembly of these two gelators was triggered. ADPMA could transform from solution to hydrogel while the solution of ADPSA formed a precipitate under the same conditions. The solution-gel/precipitate transformation can be repeated by changing the pH. In contrast to the conventional responsiveness to UV-light irradiation for azobenzene-based gels, the ADPMA hydrogel shows typical trans-cis isomerization of the azobenzene unit in solution, yet the hydrogel demonstrates remarkable stability to UV light irradiation in both the bulk gel and thin film states.
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Affiliation(s)
- Qiuhong Cheng
- Key Laboratory of Colloid and Interface Chemistry of Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100, P. R. China
| | - Yimeng Zhang
- Key Laboratory of Colloid and Interface Chemistry of Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100, P. R. China
| | - Tianxiang Luan
- Key Laboratory of Colloid and Interface Chemistry of Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100, P. R. China
| | - Zhuoer Wang
- Key Laboratory of Colloid and Interface Chemistry of Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100, P. R. China
| | - Ruipeng Tang
- Key Laboratory of Colloid and Interface Chemistry of Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100, P. R. China
| | - Pengyao Xing
- Key Laboratory of Colloid and Interface Chemistry of Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100, P. R. China
| | - Aiyou Hao
- Key Laboratory of Colloid and Interface Chemistry of Ministry of Education, School of Chemistry and Chemical Engineering, Shandong University, Jinan, 250100, P. R. China
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Dattler D, Fuks G, Heiser J, Moulin E, Perrot A, Yao X, Giuseppone N. Design of Collective Motions from Synthetic Molecular Switches, Rotors, and Motors. Chem Rev 2019; 120:310-433. [PMID: 31869214 DOI: 10.1021/acs.chemrev.9b00288] [Citation(s) in RCA: 241] [Impact Index Per Article: 48.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Precise control over molecular movement is of fundamental and practical importance in physics, biology, and chemistry. At nanoscale, the peculiar functioning principles and the synthesis of individual molecular actuators and machines has been the subject of intense investigations and debates over the past 60 years. In this review, we focus on the design of collective motions that are achieved by integrating, in space and time, several or many of these individual mechanical units together. In particular, we provide an in-depth look at the intermolecular couplings used to physically connect a number of artificial mechanically active molecular units such as photochromic molecular switches, nanomachines based on mechanical bonds, molecular rotors, and light-powered rotary motors. We highlight the various functioning principles that can lead to their collective motion at various length scales. We also emphasize how their synchronized, or desynchronized, mechanical behavior can lead to emerging functional properties and to their implementation into new active devices and materials.
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Affiliation(s)
- Damien Dattler
- SAMS Research Group, Institute Charles Sadron, CNRS , University of Strasbourg , 23 rue du Loess , BP 84047, 67034 Strasbourg Cedex 2 , France
| | - Gad Fuks
- SAMS Research Group, Institute Charles Sadron, CNRS , University of Strasbourg , 23 rue du Loess , BP 84047, 67034 Strasbourg Cedex 2 , France
| | - Joakim Heiser
- SAMS Research Group, Institute Charles Sadron, CNRS , University of Strasbourg , 23 rue du Loess , BP 84047, 67034 Strasbourg Cedex 2 , France
| | - Emilie Moulin
- SAMS Research Group, Institute Charles Sadron, CNRS , University of Strasbourg , 23 rue du Loess , BP 84047, 67034 Strasbourg Cedex 2 , France
| | - Alexis Perrot
- SAMS Research Group, Institute Charles Sadron, CNRS , University of Strasbourg , 23 rue du Loess , BP 84047, 67034 Strasbourg Cedex 2 , France
| | - Xuyang Yao
- SAMS Research Group, Institute Charles Sadron, CNRS , University of Strasbourg , 23 rue du Loess , BP 84047, 67034 Strasbourg Cedex 2 , France
| | - Nicolas Giuseppone
- SAMS Research Group, Institute Charles Sadron, CNRS , University of Strasbourg , 23 rue du Loess , BP 84047, 67034 Strasbourg Cedex 2 , France
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Ilnytskyi JM, Toshchevikov V, Saphiannikova M. Modeling of the photo-induced stress in azobenzene polymers by combining theory and computer simulations. SOFT MATTER 2019; 15:9894-9908. [PMID: 31774109 DOI: 10.1039/c9sm01853k] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
It has been shown recently that the photo-induced deformations in azobenzene-containing polymers of a side-chain architecture can be explained by means of the so-called orientational approach. The explanation is based on the following sequence of steps: (i) reorientation of azobenzenes under illumination, (ii) reorientation of the polymer backbones coupled mechanically to azobenzenes, and (iii) development of large stress in a material. Step (i) is based on the angle selective absorption of the azobenzene chromophore, which is a well established fact. Step (iii) has been validated in a series of recent theoretic studies in an infinite coupling limit. Concerning step (ii), in a real material, the backbone-azobenzene coupling will be always finite, resulting in a decrease of the effective torque sensed by the backbones and in a time delay in their reorientation. To study the relevance of these effects in detail, we perform coarse-grained molecular dynamics simulations of side-chain azobenzene-containing oligomers in bulk at conditions close to the glassy state. The focus is on the dynamical properties of such a system and on its response to the illumination, with the latter modeled either as an orientation potential applied to the azobenzenes or via their stochastic photo-isomerization. By matching the amount of light-induced stress evaluated in both cases, we obtained the equivalent orientation potential as a function of the illumination intensity and the system density.
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Affiliation(s)
- Jaroslav M Ilnytskyi
- Institute for Condensed Matter Physics of the National Academy of Sciences of Ukraine, 1, Svientsitskii Str., 79011 Lviv, Ukraine.
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Koch M, Saphiannikova M, Guskova O. Do Columns of Azobenzene Stars Disassemble under Light Illumination? LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:14659-14669. [PMID: 31627699 DOI: 10.1021/acs.langmuir.9b02960] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
The clustering properties of star-shaped molecules comprising three photochromic azobenzene-containing arms are investigated with specific focus on the influence of light on these structures. Previous experimental works report self-assembly of azobenzene stars in aqueous solution into long columnar clusters that are detectable using optical microscopy. These clusters appear to vanish under UV irradiation, which is known to induce trans-to-cis photoisomerization of the azobenzene groups. We have performed MD simulations, density functional theory, and density functional tight binding calculations to determine conformational properties and binding energies of these clusters. Our simulation data suggest that the binding strength of the clusters is large enough to prevent a breaking along their main axis. We conclude that very likely other mechanisms lead to the apparent disappearance of the clusters.
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Affiliation(s)
- Markus Koch
- Institute Theory of Polymers , Leibniz Institute of Polymer Research Dresden , Hohe Str. 6 , 01069 Dresden , Germany
| | - Marina Saphiannikova
- Institute Theory of Polymers , Leibniz Institute of Polymer Research Dresden , Hohe Str. 6 , 01069 Dresden , Germany
- Dresden Center for Computational Materials Science (DCMS) , Technische Universität Dresden , 01062 Dresden , Germany
| | - Olga Guskova
- Institute Theory of Polymers , Leibniz Institute of Polymer Research Dresden , Hohe Str. 6 , 01069 Dresden , Germany
- Dresden Center for Computational Materials Science (DCMS) , Technische Universität Dresden , 01062 Dresden , Germany
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Yadav B, Domurath J, Kim K, Lee S, Saphiannikova M. Orientation Approach to Directional Photodeformations in Glassy Side-Chain Azopolymers. J Phys Chem B 2019; 123:3337-3347. [PMID: 30896167 DOI: 10.1021/acs.jpcb.9b00614] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
To make a polymer-based material photosensitive, it is usually modified by inclusion of azobenzene (azo) chromophores. Their interaction with the light leads to conversion of absorbed energy into mechanical work. The wavelengths ∼500 nm induce cyclic trans-cis isomerization, which results in preferred orientation of the trans-isomers perpendicular to light polarization. This causes reorientation of the polymer backbones to which the azos are attached and appearance of the light-induced stress that dictates a direction of the macroscopic deformation. The directional photodeformations can be explained by an orientation approach, in which the reorientation of azos is described by the effective orientation potential. Here, we show how to calculate the time-dependent orientation state of the polymer backbones and the light-induced stress tensor. For side-chain azopolymers, a tensile stress in the direction of light polarization is predicted. Implementing the stress in a viscoplastic material model of the finite element software ANSYS, we show that a square azopolymer post elongates along the electric field vector for the linearly polarized light and contracts along the propagation direction for the circularly polarized light. These results of viscoplastic material modeling are in accordance with the experiments on light-induced reshaping of microscaled square and cylinder posts. Hence, the orientation approach works rather well for homogeneous illumination. We discuss how this approach can be used to describe surface deformations induced by complex light interference patterns.
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Affiliation(s)
- Bharti Yadav
- Leibniz-Institut für Polymerforschung , Hohe Str. 6 , 01069 Dresden , Germany
| | - Jan Domurath
- Leibniz-Institut für Polymerforschung , Hohe Str. 6 , 01069 Dresden , Germany
| | - Kwangjin Kim
- KU-KIST Graduate School of Converging Science and Technology and Department of Biomicrosystem Technology , Korea University , 02841 Seoul , Republic of Korea
| | - Seungwoo Lee
- KU-KIST Graduate School of Converging Science and Technology and Department of Biomicrosystem Technology , Korea University , 02841 Seoul , Republic of Korea
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Si Q, Feng Y, Yang W, Fu L, Yan Q, Dong L, Long P, Feng W. Controllable and Stable Deformation of a Self-Healing Photo-Responsive Supramolecular Assembly for an Optically Actuated Manipulator Arm. ACS APPLIED MATERIALS & INTERFACES 2018; 10:29909-29917. [PMID: 30047262 DOI: 10.1021/acsami.8b08025] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
It is highly challenging to achieve an optically deformable polymer with good controllability, stability, and self-healability for fabricating an optically controlled microrobotics. Here, we present a photo-responsive self-healing supramolecular assembly cross-linked by 3,3',5,5'-azobenzenetetracarboxylic acid (t-Azo) enabling the controllable and stable deformation. The network (PAA-u) of polyacrylic acid (PAA) grafted with 2-ureido-4[1 H]-pyrimidinone (UPy) is formed via multiple intermolecular hydrogen bonds (H-bonds) between UPy and t-Azo moieties. Molecular H-bonds stabilize the cis-isomer, enables stress transfer at the interface, and also contributes to fast healability. The PAA-u/t-Azo assembly shows a green-light-induced bending deformation, which recovers its shape under the irradiation of UV light. On the basis of this controllable and reversible deformation, the PAA-u/t-Azo "hand" realizes reversible light-driven grabbing and releasing of an object by optimizing bending and recovery. The assembly also shows a fast and excellent self-healing performance irradiated by green light during deformation. The multiple-H-bonding-cross-linked assembly with stable deformation and fast self-healability can be used for the development of a multitude of advanced microrobotics.
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