Anisotropic Photomechanical Response of Stretched Blend Film Made of Polycaprolactone‐Polyvinyl Ether with Azobenzene Group as Side Chain

Tanaka, Shimon; Kim, Hyun-Kyoung; Sudo, Astushi; Nishida, Haruo; Endō, Takeshi

doi:10.1002/macp.200800215

Cited by 23 publications

(11 citation statements)

References 30 publications

(64 reference statements)

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“…Photo‐isomerization of these films resulted in contraction of the film when stretching parallel to the tensile stress, and film elongation when stretching perpendicular to the tensile stress. The photo‐mechanical response was observed to increase with film stretching extent, and was speculated to arise from and anisotropic response effected by the isomerization‐induced vibration of azobenzene units, which decreased the modulus of the amorphous area being deformed . Other polymer film systems that exhibited large bending angles (90°), and high bending intensities have since been also reported …”

Section: Photo‐mechanical Effectsmentioning

confidence: 97%

Shape‐Shifting Azo Dye Polymers: Towards Sunlight‐Driven Molecular Devices

Bushuyev

Aizawa

Shishido

et al. 2017

Macromol. Rapid Commun.

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The development of stimuli-responsive polymers is among the key goals of modern materials science. The structure and properties of such switchable materials can be designed to be controlled via various stimuli, among which light is frequently the most powerful trigger. Light is a gentle energy source that can target materials remotely, and with extremely high spatial and temporal resolution easily and cheaply. Reversible light-control over molecular mechanical properties in particular has in recent years attracted great interest due to potential applications as optical-to-mechanical conversion actuators and 'devices', enabling 'molecular robotic machines'. In this review, some recent examples and emerging trends in this exciting field of research are highlighted, covering a wide variety of polymer hosts that contain azobenzene photo-reversible switches. It is hoped that this review will help stimulate more interest towards the development of light-reversible materials for energy harvesting and conversion, and their successful incorporation into a wide variety of current and future high-tech applications in devices.

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Section: Photo‐mechanical Effectsmentioning

confidence: 97%

Shape‐Shifting Azo Dye Polymers: Towards Sunlight‐Driven Molecular Devices

Bushuyev

Aizawa

Shishido

et al. 2017

Macromol. Rapid Commun.

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“…Hence, photoisomerization behavior was observed for all polymers, irrespective of the lengths of their methylene spacers. It should be noted that the spectral changes in the present study are more dramatic than those of a previous azobenzene‐based PVE with a cross‐linked structure, which highlights the efficient photoreactivities of our systems. The difference in the λ max value in a film compared to that in solution is known to be an index of the degree of aggregation of the azobenzene moiety (Table ) .…”

Section: Resultsmentioning

confidence: 54%

Semicrystalline poly(vinyl ether)s with high and phototunable glass transition temperature: application for thermally stable and reworkable adhesives

Ito

Akiyama

Mori

et al. 2020

Journal of Polymer Science

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The photoinduced solid–liquid phase transition of azobenzene‐based polymers is an attractive method to synthesize stimuli‐responsive functional materials. As the structure–property relationships of such materials are not fully understood, a new class of polymer backbone, that is, poly(vinyl ether) (PVE), was studied for the development of azobenzene‐based polymers with high thermal stability. For this purpose, a series of azobenzene‐based PVEs with different monomer structures were synthesized using a Lewis acid catalyst‐based cationic polymerization method. Typical PVEs are viscous polymers with low glass‐transition temperatures (Tg's). The flexibility of the polymer backbone improves with the use of alkylene spacers, changing the order of alignment of the mesogenic azobenzene moieties attached to the backbone, leading to high Tg's of the azobenzene‐based PVEs. One of the synthesized PVEs shows a high glass‐transition temperature of 94 °C, which is 14 °C higher compared to that of the corresponding polymethacrylate. Furthermore, the PVE exhibits photoinduced solid–liquid phase transition from the semicrystalline state. This phase transition material, with its high thermal stability, has the potential for broader applications, such as for the phototuning of adhesion. © 2020 Wiley Periodicals, Inc. J. Polym. Sci. 2020, 58, 568–577

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“…In other studies, similar films of azobenzene‐containing vinyl ethers with polycaprolactone achieved a “rapid” (at that time, a few seconds) anisotropic shape deformation and recovery. This photomechanical response was reported to increase with the extent of film stretching, and it was proposed to arise from an anisotropic response effected by the isomerization‐induced vibration of azobenzene groups, which lowered the modulus of the amorphous regions being deformed …”

Section: Polymeric Photoactuators: Moving Toward Artificial Musclesmentioning

confidence: 99%

Photoreversible Soft Azo Dye Materials: Toward Optical Control of Bio‐Interfaces

Chang

Fedele

Priimägi

et al. 2019

Advanced Optical Materials

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systems interact with artificial materials, researchers have now assembled a versatile toolkit of materials and processes that allows one to fine-tune interactions at the interface, tailoring specific biological responses on demand. These strategies for biocontrol can be broadly categorized as chemical (charge, ligand presence, surface groups), material changes (moisture content, stiffness), or morphological changes (molecular orientation, surface topography, or mechanical actuation). Rational design of materials for biological interface applications has a unique set of challenges due to the unique requirements of a wide range of biological systems, since different tissues present specific compositions, with their own elasticity, structural organization, and triggering mechanisms. Even within a single organ or tissue, mechanical properties can vary widely depending on the region. A recent study of viscoelasticity in live mouse brain tissue for example found a tenfold difference within the brain depending on the region and morphological structure studied. [2] However, most biological tissues are far less stiff, and far more viscoelastic than typical artificial materials employed at their interface, especially early artificial cell culture materials, which can be much stiffer than in vivo extracellular matrix by many orders of magnitude. [3] In vivo, cells interface with a surrounding microenvironment consisting of an intricate macromolecular network of proteins and sugars swollen in an aqueous media gel. Therefore, the interaction between cells and the extracellular matrix (ECM) in the body is complex and involves a variety of cues related to topography, chemical markers, protein composition, solubility factors, and mechanical properties such as stiffness and elasticity (Figure 1a). [4] Yet much research over the past decades was focused on studying in vitro the effects of each of these signals on cell behavior, with a particular interest on the chemical factors, whereas only recently more advanced biomaterials with controlled physicomechanical properties have been developed, such as those with tunable and variable stiffness, alignment and orientation of key functional groups, and mechanical actuation. There is a large range of stiffness in human tissue, where bone (≈100 GPa) is nine orders of magnitude harder than brain tissue (≈0.1 kPa). [4] Therefore, biomaterial researchers assume a complex task of providing materials and processing technologies for controlling stiffness and micro-and nanostructures in Photoreversible optically switchable azo dye molecules in polymer-based materials can be harnessed to control a wide range of physical, chemical, and mechanical material properties in response to light, that can be exploited for optical control over the bio-interface. As a stimulus for reversibly influencing adjacent biological cells or tissue, light is an ideal triggering mechanism, since it can be highly localized (in time and space) for precise and dynamic control over a biosystem, and low-power visible light...

show abstract

Anisotropic Photomechanical Response of Stretched Blend Film Made of Polycaprolactone‐Polyvinyl Ether with Azobenzene Group as Side Chain

Cited by 23 publications

References 30 publications

Shape‐Shifting Azo Dye Polymers: Towards Sunlight‐Driven Molecular Devices

Shape‐Shifting Azo Dye Polymers: Towards Sunlight‐Driven Molecular Devices

Semicrystalline poly(vinyl ether)s with high and phototunable glass transition temperature: application for thermally stable and reworkable adhesives

Photoreversible Soft Azo Dye Materials: Toward Optical Control of Bio‐Interfaces

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