Photochromic Bulk Materials

Morimoto, Masakazu; Kobatake, Seiya; Irie, Masahiro; Bisoyi, Hari Krishna; Li, Quan; Wang, Sheng; Tian, He

doi:10.1002/9783527683734.ch8

Cited by 5 publications

(4 citation statements)

References 253 publications

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“…By definition, photochromism is the phenomenon of reversible transformation of a chemical species between two isomeric forms by the absorption of electromagnetic radiation, where the two forms display different absorption spectra and some distinct physical properties. − If the photochromic chemical compounds are colored, they would exhibit color change upon exposure to light of appropriate wavelength. The reversible structural changes by absorption of appropriate wavelength of light qualify such materials as light-driven molecular switches or motors.…”

Section: Introductionmentioning

confidence: 99%

Light-Driven Liquid Crystalline Materials: From Photo-Induced Phase Transitions and Property Modulations to Applications

2016

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Light-driven phenomena both in living systems and nonliving materials have enabled truly fascinating and incredible dynamic architectures with terrific forms and functions. Recently, liquid crystalline materials endowed with photoresponsive capability have emerged as enticing systems. In this Review, we focus on the developments of light-driven liquid crystalline materials containing photochromic components over the past decade. Design and synthesis of photochromic liquid crystals (LCs), photoinduced phase transitions in LC, and photoalignment and photoorientation of LCs have been covered. Photomodulation of pitch, polarization, lattice constant and handedness inversion of chiral LCs is discussed. Light-driven phenomena and properties of liquid crystalline polymers, elastomers, and networks have also been analyzed. The applications of photoinduced phase transitions, photoalignment, photomodulation of chiral LCs, and photomobile polymers have been highlighted wherever appropriate. The combination of photochromism, liquid crystallinity, and fabrication techniques has enabled some fascinating functional materials which can be driven by ultraviolet, visible, and infrared light irradiation. Nanoscale particles have been incorporated to widen and diversify the scope of the light-driven liquid crystalline materials. The developed materials possess huge potential for applications in optics, photonics, adaptive materials, nanotechnology, etc. The challenges and opportunities in this area are discussed at the end of the Review.

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Section: Introductionmentioning

confidence: 99%

Light-Driven Liquid Crystalline Materials: From Photo-Induced Phase Transitions and Property Modulations to Applications

2016

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“…The physical properties of a polymer matrix, in particular its stiffness/softness and the amount of polymer free volume can impede or allow the required dynamic motion on the molecular level during photoswitching. [39,40] Therefore, we utilized in situ photorheology (Figure S7) to assess the mechanical properties and photoreactivity of the resulting networks.…”

Section: Network Structure and Mechanical Propertiesmentioning

confidence: 99%

Nano-3D-printed Photochromic Objects

Ulrich¹,

Wang²,

Rottmar³

et al. 2020

Preprint

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A new class of photoresist is described for direct laser writing of photoswitchable 3D microstructures. The material comprising off-stoichiometric thiol-ene photo-clickable resins enables rapid two-photon laser processing of highly complex structures and facile post-modification with photoswitches. The microstructures were functionalized with a series of donor-acceptor Stenhouse adducts (DASAs) photoswitches with different excitation wavelength. The versatility of thiol–ene photo-click reaction enabled fine-tuning of the network structure and physical properties as well as the type and concentration of DASA photoswitches. When exposed to visible light, these microstructures exhibit excellent photo-responsiveness and undergo reversible color-changing via photoisomerization of DASA moieties. We describe that the weak fluorescence of DASAs can be used as a reporter of photoswitching, color changes, and thermal recovery, allowing the reading of DASA-containing sub-micrometric structures in 3D. This work delivers a new approach for custom microfabrication of 3D photochromic objects with molecularly engineered color and responsiveness.

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“…In general, the relative ease of photoisomerization depends on the position of the photochromic unit in the polymer chain, with photoisomerization being the fastest in free dyes, followed by chain ends, as the pendant group and the slowest when present in the middle of the polymer chain. − Recently, fast photochromic switching was reported in polymers tethered with one photochromic unit per chain. ,,− However, initiation was slow, the molecular weight of the polymers obtained was low, and by using these photochromic unit tethered initiators it was challenging to polymerize functional monomers. − In order to make the process of forming photochromic materials environmentally friendly, various photochromic polymers and glasses have been prepared by dispersing the dye in solid matrixes. , …”

Section: Introductionmentioning

confidence: 99%

“…41−45 In order to make the process of forming photochromic materials environmentally friendly, various photochromic polymers and glasses have been prepared by dispersing the dye in solid matrixes. 46,47 Developing smart materials based on photoresponsive functionality sustainably has been of high interest in the past few years. 48−50 A general method of preparing vinyl polymers tethered with photochromic units in the chain end by making use of a hitherto unknown photochromic azo-initiator is reported in this article.…”

Section: ■ Introductionmentioning

confidence: 99%

Cast, Dip, Spray, and Print─Covalently Embedded Photochromic Materials from a Versatile Spiropyran Conjugate

Vasantha

Chen

Zhao

et al. 2023

ACS Appl. Polym. Mater.

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Dynamic photochromic dyes are in great demand for various applications. These are used as active materials with tunable optical properties. However, producing photochromic materials in significant quantities is still a challenge. The ability to retain and prolong the interconversion of switching between open and closed forms is affected by undesirable aggregation of dyes in the matrix. The often-employed method of adding photochromic dyes into bulk materials causes issues such as aggregation, leaching of dye, and photoinstability. A versatile light-responsive spiropyran substituted azo-initiator was conveniently synthesized and utilized for incorporating photochromic units at the α-chain end of the vinyl polymers. Accordingly, processes in bulk, solution, and emulsion/dispersion were developed by radical polymerization of common vinyl monomers such as styrene and acrylates. This approach enabled the preparation of light-responsive polymers possessing photochromic spiropyran units covalently incorporated at the polymer chain end. Thus, monodisperse, covalently embedded photochromic colloidal particles with low dye content (<0.1 mmol) were prepared. The fabrication and high-resolution spatiotemporal control of materials such as gels, elastomers, resins, and transparent films of commodity polymers embedded with photochromic units are demonstrated with detailed coloring, fading, and fatigue behavior. The facile and straightforward approach developed to prepare photochromic colloidal particles can be applied to any substrate through cast, dip, spray, or print to make “smart” photochromic materials.

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Photochromic Bulk Materials

Cited by 5 publications

References 253 publications

Light-Driven Liquid Crystalline Materials: From Photo-Induced Phase Transitions and Property Modulations to Applications

Light-Driven Liquid Crystalline Materials: From Photo-Induced Phase Transitions and Property Modulations to Applications

Nano-3D-printed Photochromic Objects

Cast, Dip, Spray, and Print─Covalently Embedded Photochromic Materials from a Versatile Spiropyran Conjugate

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