• Macromolecular Research
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• 제8권3호
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• pp.137-141
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• 2000

3,4-Di-(2'-hydroxyethoxy)-4-nitrostilbene (2) was prepared by the reaction of 2-iodoethanol with 3,4-dihydroxy-4-nitrostilbene (1). Diol 2 was condensed with 2,4-toluenediisocyanate ,3,3-dimethoxy-4,4'-biphenylenediisocyanate , and 1,6-hexamethylenediisocyanate to yield polyurethanes 3, 4, and 5 containing the NLO-chromophore. Polymers 3-5 were soluble in common organic solvents such as acetone and DMSO. The glass transition temperatures(T$\sub$g/) of the resulting polymers 3-5 were obseved around 100-114$^{\circ}C$. Electrooptic coefficients (r$\sub$33/) of the poled polymer films were in the range of 18-25 pm/V at 633 nm. Polymers 3-5 began to decompose around 250$^{\circ}C$ in TGA thermograms.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2002년도 International Meeting on Information Display
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• pp.479-482
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• 2002

Benzylideneacetophenones are known as chalcones[1]. The chalcone has been known to be a photo-isomerizable and photo-dimerizable chromophore. The chalcone derivatives were prepared by base-catalyzed condensation of aldehydes and acetophenones, which were substituted with various alkyl chains. The synthesized chalcone was introduced into the t-BOC protected diamine through William synthesis reaction. Photocrosslinkable polyimide was prepared via one-step imidization reaction of DOCDA (5-(2,5-dioxotetrahydro furyl}-3-methyl-3-cyclohexene-1,2-dicarboxylic anhydride) and the chalcone introduced diamine using isoquinoline (5 wt%) in m-cresol. The polyimide solutions were spin-coated onto the quartz, silicone wafer and glass substrates and the obtained thin films were irradiated obliquely with linearly polarized UV light.

• Journal of Pharmaceutical Investigation
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• 제12권4호
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• pp.132-144
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• 1982

The inclusion of ${\beta}-cyclodextrin$ $({\beta}-CyD)$ with prothionamide in aqueous phase was investigated by circular dichroism(CD), ultraviolet (UV) absorption, and solubility technique. The results suggested that a region of drug chromophore was located within the asymmetric center of ${\beta}-cyclodextrin$. Solubility and spectral changes were quantitatively treated to obtain stoichiometric ratio, which was found to be 1 : 1, and formation constants which were determined by solubility, CD, and UV method were 257, 367, and 389 $M^{-1}$, respectively. Also, the formation constant of the inclusion complex was determined by CD method at various pH. The result was that $K_c$ depended upon the pH of medium, and this fact also supported that thioamide moiety was accomodated in the cavity of ${\beta}-cyclodextrin$.

• 한국재료학회지
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• 제6권12호
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• pp.1242-1247
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• 1996

Spatially fixed bichromophoric systems with nonidentical chromophores have been extensively employed for studies of electron transfer and excitation transfer. Excitation hopping behavior between two naphthy1 moieties on 7,14-dihydro-7,14-ethanodibenz[a,h] anthracene(DEA)has been explored by the time-resolved fluorescence anisotropy measurements. The experimentally obtained value of the hopping rate in DEA agrees at least qualitatively with that calculated on the basis of the Dexter's theory, but disagrees with that calculated on the basis of the Forster's theory, indicates that for a pair of donor and acceptor with inter-chromophore separation as short as 4.5 $\AA$, excitation transfer via electron exchange is a predominant process.

• 한국염색가공학회지
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• 제26권3호
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• pp.165-172
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• 2014

Novel super hydrophobic orange dyes having maximum absorption band at 450-500nm were synthesized to dye polyolefin fibers such as polypropylene and ultra high molecular weight polyethylene fibers, using 4-alkylanilines and ${\beta}$-naphthol. Their absorption spectra at visible range showed almost the same, which meant that the alkyl substituents introduced to chromophore did not affect on color appearance of the dyes. Considering both color strength and wash fastness, the decyl-substituted dye was determined as the optimum one practically. From the dyeing results at various conditions, the optimum dyeing was $130^{\circ}C$ for 1 hour with 5% owf of dyes. The good fastness ratings to washing, rubbing were obtained showing 4-5 for both fibers. Light fastness was also acceptable giving rating 3-4 for polypropylene fibers and rating 3 for ultra high molecular weight polyethylene fibers.

• 한국염색가공학회지
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• 제24권2호
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• pp.106-112
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• 2012

As a subsequent research of the previously reported$^{9)}$, a series of diaminoanthraquinoid blue dyes having hexyl, heptyl and octyl substituents were newly synthesized in order to investigate dyeability toward polypropylene fibers. As the length of alkyl groups introduced to the chromophore increased, the dyeability of the dyes toward polypropylene fibers also increased and then gradually decreased. From the result of dyeing, the hexyl-substituted dye showed the highest color strength and deep shade on pure polypropylene fibers. The good fastness rates to wash, rubbing and light were also obtained for all of the synthesized dyes.

• Molecules and Cells
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• 제43권6호
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• pp.509-516
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• 2020

To perceive fluctuations in light quality, quantity, and timing, higher plants have evolved diverse photoreceptors including UVR8 (a UV-B photoreceptor), cryptochromes, phototropins, and phytochromes (Phys). In contrast to plants, prokaryotic oxygen-evolving photosynthetic organisms, cyanobacteria, rely mostly on bilin-based photoreceptors, namely, cyanobacterial phytochromes (Cphs) and cyanobacteriochromes (CBCRs), which exhibit structural and functional differences compared with plant Phys. CBCRs comprise varying numbers of light sensing domains with diverse color-tuning mechanisms and signal transmission pathways, allowing cyanobacteria to respond to UV-A, visible, and far-red lights. Recent genomic surveys of filamentous cyanobacteria revealed novel CBCRs with broader chromophore-binding specificity and photocycle protochromicity. Furthermore, a novel Cph lineage has been identified that absorbs blue-violet/yellow-orange light. In this minireview, we briefly discuss the diversity in color sensing and signal transmission mechanisms of Cphs and CBCRs, along with their potential utility in the field of optogenetics.

• Bulletin of the Korean Chemical Society
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• 제23권7호
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• pp.957-963
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• 2002

We successfully synthesized the addition-type polynorbonenes (PNB) exhibiting photochromic properties and excellent thermal stability. Three norbornene-based monomers with different azobenzene moiety (R=NO2, H,OCH3) were synthesized by transesterification method. The corresponding PNB copolymers were synthesized by transition metal-catalyzed addition polymerization method, and characterized by GPC, UV-Vis spectroscopy, NMR, and thermal analysis. For comparison of the photochromic properties depending on the rigidity of polymer backbone, we prepared the polymethylmethacrylate (PMMA) copolymer with the corresponding azobenzene moiety. We investigated the photoisomerization behavior by means of optical muitichannel analyzer with Xe lamp as well as real-time UV-Vis spectroscopy with high-pressure mercury lamp. Among three PNB copolymers, a polymer with azobenzene (R=H) was the most adaptable for observation of photoisomerization behavior. It was found that the rate of photoisomerization and relaxation depended on the structure of azobenzene chromophore, rather than that of polymer backbone.

• Bulletin of the Korean Chemical Society
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• 제23권4호
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• pp.571-574
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• 2002

The photorefractive polymeric composite with good performance was prepared. The carbazole-substituted polysiloxane sensitized by 2,4,7-trinitro-9-fluorenone was used as a photoconducting medium and 1-[4-(2-nitrovinyl)phenyl]piperidine was added as an optically nonlinear chromophore. The photorefractive property of polymer was determined by diffraction efficiency using a 100 ㎛-thick film. The maximum diffraction efficiency ( ηmax) of 71% was obtained at the electric field of 70 V/ ㎛. The potential of the current polymer material as a holographic recording medium was evaluated by the demonstration of holographic recording and subsequent reading of optical image.

• Bulletin of the Korean Chemical Society
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• 제24권12호
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• pp.1727-1728
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• 2003