Benzospiropyrans as photochromic and/or thermochromic photoinitiators

Lee, Suk Kyu; Neckers, Douglas C.

doi:10.1021/cm00017a021

Cited by 11 publications

(9 citation statements)

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“…In our system, the writing step is based on a highly selective, high-yielding reaction of one of the two photoisomers of our photochromic system, which cross-links the linear polymer chains and produces an insoluble gel network. A possible alternative strategy is the use of photochromic molecules as photoinitiatiors. , …”

Section: Introductionmentioning

confidence: 99%

Spirothiopyran-Based Reversibly Saturable Photoresist

2017

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Super-resolution lithography holds the promise of achieving three-dimensional (3D) nanopatterning at deep subwavelength resolutions with high throughput. 3D super-resolution lithography schemes demonstrated thus far have all been serial in nature, primarily due to the lack of a photoresist chemistry that not only couples a saturable reversibly switchable reaction with a writing step but also has a low saturation threshold. Here, we demonstrate that combining the reversible photoisomerization of spirothiopyran with the thiol-Michael conjugate addition reaction achieves the necessary photochemical characteristics. Green light was found to saturate inhibition of the thiol-Michael addition writing step at very low intensity thresholds. By formulating a spirothiopyran-functionalized polyethylene glycol copolymer, we demonstrate spatial control over cross-linking using inhibition by green light. Kinetics measurements combined with photokinetic simulations show that interference lithography on a spirothiopyran maleimide-based writing system using conventional light sources (e.g., a 2 W green laser) should deliver super-resolution features (∼45 nm wide lines) in thick films (tens of microns) over large areas (hundreds of microns on a side). The unique combination of reversible photochromic switching of spirothiopyran with the thiol-Michael addition reaction marks an important step toward realizing a highly parallelized 3D super-resolution writing system.

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Section: Introductionmentioning

confidence: 99%

Spirothiopyran-Based Reversibly Saturable Photoresist

2017

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“…Since then, a multitude of substitution patterns have been synthesized [ 11 , 56 ], whereas the first detailed report on the photo-response of this class of molecules was published by Fischer et al in 1954 [ 57 ]. Benzospiropyrane molecules mainly switch to the open form upon irradiation at 365 nm and close the ring typically triggered by irradiation at 560 nm [ 58 , 59 , 60 ]. Copolymers containing a spiropyrane moiety were intensively studied by Smets in 1972, including a copolymer with MMA synthesized via free radical polymerization [ 61 ].…”

Section: λ-Dependent Photo-response In Block Copolymer Nanostructumentioning

confidence: 99%

Micellization of Photo-Responsive Block Copolymers

2017

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This review focuses on block copolymers featuring different photo-responsive building blocks and self-assembly of such materials in different selective solvents. We have subdivided the specific examples we selected: (1) according to the wavelength at which the irradiation has to be carried out to achieve photo-response; and (2) according to whether irradiation with light of a suitable wavelength leads to reversible or irreversible changes in material properties (e.g., solubility, charge, or polarity). Exemplarily, an irreversible change could be the photo-cleavage of a nitrobenzyl, pyrenyl or coumarinyl ester, whereas the photo-mediated transition between spiropyran and merocyanin form as well as the isomerization of azobenzenes would represent reversible response to light. The examples presented cover applications including drug delivery (controllable release rates), controlled aggregation/disaggregation, sensing, and the preparation of photochromic hybrid materials.

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“…Holographic recording with organic polymer materials has been studied intensively in order to achieve high efficiency, low cost, and high storage density [6,7,8]. …”

Section: Introductionmentioning

confidence: 99%

“…The development of photopolymer materials has become one of the most dynamic developing branches of holography [ 1 , 2 , 3 , 4 , 5 ]. Holographic recording with organic polymer materials has been studied intensively in order to achieve high efficiency, low cost, and high storage density [ 6 , 7 , 8 ].…”

Section: Introductionmentioning

confidence: 99%

Nopal Cactus (Opuntia Ficus-Indica) as a Holographic Material

2012

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The nopal cactus (Opuntia ficus-indica) releases a substance through its mucilage, which comes from the degradation of pectic substances and chlorophyll. Combined in a polyvinyl alcohol matrix, this substance can be used as a recording medium. The resulting extract material has excellent photosensitizer properties, is easy to handle, has a low cost, and low toxicity. This material has the property of self-developing, and it can be used in holographic applications. The polyvinyl alcohol and extract from the nopal cactus was deposited by a gravity technique on a glass substrate, which dried to form a photosensitive emulsion. We show experimental results on a holographic grating using this material, written by a He-Cd laser (442 nm). We obtained diffraction gratings by transmission with a diffraction efficiency of approximately 32.3% to first order.

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Benzospiropyrans as photochromic and/or thermochromic photoinitiators

Cited by 11 publications

References 0 publications

Spirothiopyran-Based Reversibly Saturable Photoresist

Spirothiopyran-Based Reversibly Saturable Photoresist

Micellization of Photo-Responsive Block Copolymers

Nopal Cactus (Opuntia Ficus-Indica) as a Holographic Material

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