The Experts below are selected from a list of 267 Experts worldwide ranked by ideXlab platform

Georgina K. Such - One of the best experts on this subject based on the ideXlab platform.

  • the generic enhancement of photochromic dye switching speeds in a rigid polymer matrix
    Nature Materials, 2005
    Co-Authors: Georgina K. Such, Richard A. Evans, Tracey Hanley, Melissa A Skidmore, Thomas P Davis
    Abstract:

    The switching or isomerization speed of photochromic dyes in a rigid polymeric matrix (such as an Ophthalmic Lens) is generally significantly slower than that observed in the mobile environment of a solution. Here we describe that the attachment of flexible oligomers having a low glass-transition temperature—such as poly(dimethylsiloxane)—to photochromic dyes greatly increases their switching speeds in a rigid polymer matrix. The greatest impact was observed in the thermal fade parameters T1/2 and T3/4—the times it takes for the optical density to reduce by half and three quarters of the initial optical density of the coloured state—which were reduced by 40–95% and 60–99% respectively for spirooxazines, chromenes and an azo dye in a host polymer with a glass-transition temperature of 120 °C. The method does not alter the electronic nature of the dyes but simply protects them from the host matrix and provides greater molecular mobility for the switching process. In addition to Ophthalmic Lenses, the generic nature of the method may find further utility in data recording or optical switching.

A-young Sung - One of the best experts on this subject based on the ideXlab platform.

  • Study on Dispersant and Surface Analysis of Ophthalmic Lens Materials Containing Carbon Nanotubes.
    Journal of nanoscience and nanotechnology, 2021
    Co-Authors: Su-mi Shin, A-young Sung
    Abstract:

    In this study, two types of carbon nanotubes were used as Ophthalmic material, and hydrogel contact Lenses were polymerized by adding two types of dispersants to effectively exert the functions of carbon nanotubes. The physical properties and surfaces of the Ophthalmic hydrogel Lenses prepared to confirm the functionality as a dispersant were compared and analyzed to find the utility as an Ophthalmic Lens material. For the polymerization, single-walled carbon nanotubes (SWCNTs), single-walled carbon nanotubes carboxylic acid functionalized (SWCCNTs), 2-hydroxyethyl methacrylate (HEMA), ethylene glycol dimethacrylate (EGDMA, a crosslinking agent), and azobisisobutyronitrile (AIBN, an initiator) was used. In addition, as a dispersant, PVP (polyvinylpyrrolidone) and BYK-111 were copolymerized. As a result of this study, PVP increased the water content and decreased refractive index regardless of the type of carbon, whereas BYK-111 did not show a significant difference in basic properties. Also, PVP gradually decreased breaking strength, while BYK-111 gradually increased breaking strength. BYK-111 effectively exerted the function of carbon nanotubes, and it was confirmed whether it was dispersed through TEM. Therefore, if carbon nanotubes are used as Ophthalmic materials by utilizing BYK-111, it considered to be used as functional Ophthalmic Lens materials.

  • Polymerization and Preparation of High Functional Ophthalmic Lens Material Containing 2-Fluoro Styrene with Si and Ag Nanoparticles
    Science of Advanced Materials, 2020
    Co-Authors: Min-jae Lee, A-young Sung
    Abstract:

    This research was conducted to produce the high functional silicone hydrogel Ophthalmic Lens containing styrene group and nanoparticles. 2F (2-fluorostyrene) was added to enhance polymerization stability during Lens formation, Si and Ag nanoparticles were used as additives for the basic combination including Sil-H (Silicone monomer), TSMA (Trimethylsilyl methacrylate), DMA (N,N-Dimethylacetamide) and MMA (methyl methacrylate). And also, the materials were copolymerized with EGDMA (ethylene glycol dimethacrylate) as the crosslinking agent and AIBN (azobisisobutyronitrile) as the initiator. Measurement of the physical, optical, surface and antimicrobial characteristics of the produced material showed the possibility of utilization as an opthalmic contact Lens. As a result of the polymerization stability measurement, no significant difference was observed in all the samples, so it can be judged that the stabilization of nanoparticles in the polymer was maintained. Therefore, these materials are expected to satisfy the basic requirements of Ophthalmic Lenses and used usefully as an antimicrobial material for silicone hydrogel Ophthalmic Lens.

  • Preparation and Characterization of Ophthalmic Lens Materials Containing Titanium Silicon Oxide and Silver Nanoparticles.
    Journal of nanoscience and nanotechnology, 2015
    Co-Authors: Don-kyu Kim, Min-jae Lee, Tae Hyeon Kim, A-young Sung
    Abstract:

    Hydrogel Ophthalmic Lenses containing fluorine-substituted aniline group, titanium silicon oxide nartoparticles, and silver nanoparticles were copolymerized, and the physical and optical properties of the hydrogel Lenses were measured. To produce the hydrophilic Ophthalmic Lenses, the additives were added to the mixture containing HEMA, NVP, MA, EGDMA, and AIBN. The cast mold method was used for the manufacture of the hydrogel Ophthalmic Lenses, and the produced Lenses were completely soaked in a 0.9% NaCl normal saline solution for 24 hours for hydration. The physical properties of the produced macromolecule showed that the water content was 32.5-37.6%, the refractive index was 1.450-1.464, the UV-B transmittance was 0.5-35.2%, and the contact angle was between 56 and 69°. Also, the addition of aniline, titanium silicon oxide, and silver nanoparticles allowed the Ophthalmic Lenses to block UV. These results show that the produced macromolecule can be used as hydrophilic Lenses for ophthalmologic purposes that can block UV.

  • Optical application of poly(HEMA-co-MMA) containing silver nanoparticles and N,N-dimethylacrylamide
    Korean Journal of Chemical Engineering, 2012
    Co-Authors: A-young Sung, Tae-hun Kim
    Abstract:

    High functional Ophthalmic Lens materials, poly(HEMA- co -MMA)s, were prepared by the copolymerization of HEMA, MMA, NVP, EDGMA, and N,N-dimethylacrylamide in the presence of silver nanoparticles. Silver nanoparticles have antimicrobial properties and a hydrophilic monomer N,N-dimethylacrylamide has excellent biocompatibility and oxygen transmissibility. The water content was in the range of 36.63–44.45%, indicating the characteristics of general water-content contact Lenses, and the refractive index was measured to be in the range of 1.423–1.435. Meanwhile, the oxygen transmissibility ranged from 10.63×10^−11 to 18.85×10^−11 (cm^2/sec)(mlO_2/ml×mmHg) increasing with increasing the addition ratio of N,N-dimethylacrylamide. The polymeric materials satisfied the basic characteristics required for Ophthalmic contact Lenses. The polymers can be used to fabricate antimicrobial hydrogel contact Lenses with high oxygen transmissibility.

Richard A. Evans - One of the best experts on this subject based on the ideXlab platform.

  • the generic enhancement of photochromic dye switching speeds in a rigid polymer matrix
    Nature Materials, 2005
    Co-Authors: Georgina K. Such, Richard A. Evans, Tracey Hanley, Melissa A Skidmore, Thomas P Davis
    Abstract:

    The switching or isomerization speed of photochromic dyes in a rigid polymeric matrix (such as an Ophthalmic Lens) is generally significantly slower than that observed in the mobile environment of a solution. Here we describe that the attachment of flexible oligomers having a low glass-transition temperature—such as poly(dimethylsiloxane)—to photochromic dyes greatly increases their switching speeds in a rigid polymer matrix. The greatest impact was observed in the thermal fade parameters T1/2 and T3/4—the times it takes for the optical density to reduce by half and three quarters of the initial optical density of the coloured state—which were reduced by 40–95% and 60–99% respectively for spirooxazines, chromenes and an azo dye in a host polymer with a glass-transition temperature of 120 °C. The method does not alter the electronic nature of the dyes but simply protects them from the host matrix and provides greater molecular mobility for the switching process. In addition to Ophthalmic Lenses, the generic nature of the method may find further utility in data recording or optical switching.

James Robinson Ltd - One of the best experts on this subject based on the ideXlab platform.

  • Grey Colouring Photochromic Fused Pyrans
    2000
    Co-Authors: Clarke, David A., Heron B. Mark, Gabbutt, Christopher D., Hepworth, John D., Partington, Steven M., Corns, Stephen N., James Robinson Ltd
    Abstract:

    A photochromic grey colouring 2$i(H)-naphtho[1,2-$i(b)]pyran of formula (I) wherein R?1¿ is selected from mono-, di- or poly-substituted aryl groups, mono-, di- or poly-substituted naphthyl groups and mono-, di- or poly-substituted heteroaryl groups, wherein at least one substituent is a nitrogen containing group, including amino, C¿1?-C¿20? and C¿6?-C¿20? alkylamino, C¿1?-C¿20? and C¿6?-C¿20? dialkylamino, C¿2?-C¿20? dialkenylamino, C¿2?-C¿20? or C¿4?-C¿20? di(polyalkenyl)amino, arylamino, diarylamino, C¿1?-C¿20? alkylarylamino, tetra (C¿1?-C¿10? linear or branched alkyl) guanidino and cyclic-amino groups and at least one of R?7¿ and R?9¿, which may be the same or different, is selected from C¿1?-C¿20? $i(N) alkylamino C¿1?-C¿20? $i(N)-alkylamido, C¿1?-C¿20? $i(N,N)-dialkylamido, amido, nitro, amino, C¿1?-C¿20? alkylamino, C¿1?-C¿20? dialkylamino, C¿2?-C¿20? dialkenylamino, C¿4?-C¿20? di(polyalkenyl)amino, arylamino, diarylamino, C¿1?-C¿20? alkylarylamino, or cyclicamino groups. The compounds may be combined with a polymeric host material such as plastic or glass to make a sunglass Lens, an Ophthalmic Lens or a window. The compounds may also be included in an ink or a fuel

  • Photochromic Substituted 2H-Naphtho[1,2-b]pyrans
    2000
    Co-Authors: Clarke, David A., Heron B. Mark, Gabbutt, Christopher D., Hepworth, John D., Partington, Steven M., Corns, Stephen N., James Robinson Ltd
    Abstract:

    A 2$i(H)-naphtho[1,2-$i(b)]pyran of general formula (I) wherein R?5¿ is substituted and where R?8¿ is selected from the substituents including hydrogen, linear or branched C¿1?-C¿20? alkyl, C¿3?-C¿20? cycloalkyl, C¿4?-C¿20? bicycloalkyl, C¿5?-C¿20? polycycloalkyl, linear or branched C¿1?-C¿20? haloalkyl, linear or branched C¿1?-C¿20? perhaloalkyl, linear or branched C¿2?-C¿20? alkenyl, linear or branched C¿4?-C¿20? polyalkenyl, linear or branched C¿2?-C¿20? alkynyl, linear or branched C¿4?-C¿20? polyalkynyl, linear or branched C¿1?-C¿20? hydroxyalkyl, linear or branched C¿1?-C¿20? alkylcarbonyl, linear or branched C¿1?-C¿20? polyhydroxyalkyl, linear or branched C¿1?-C¿20? alkoxy, linear of branched C¿1?-C¿20? alkylthio, linear or branched C¿1?-C¿20?(C¿1?-C¿5? or C¿1?-C¿10?alkoxy)alkyl, linear or branched C¿1?-C¿20?(C¿1?-C¿5? or C¿1?-C¿10?alkylthio)alkyl, benzoyl, aroyl, heteraroyl, phenyl, aryl, heteroaryl, halogen, hydroxyl, formyl, acetyl, linear or branched C¿3?-C¿20? alkenoyl, linear or branched C¿5?-C¿20? polyalkenoyl, nitrile, carboxyl, C¿1?-C¿20? or C¿1?-C¿5? alkoxycarbonyl, C¿1?-C¿20? $i(N)-alkylamido, C¿1?-C¿20? or C¿1?-C¿5? $i(N, N)-dialkylamido, amido, nitro, amino, C¿1?-C¿20? or C¿1?-C¿5? alkylamino, C¿1?-C¿20? dialkylamino, C¿2?-C¿20? dialkenylamino, C¿4?-C¿20?di(polyalkenyl)amino, arylamino, diarylamino, C¿1?-C¿20? alkylarylamino, cyclic-amino groups, arylsulfanyl, aryloxy, arylsulfinyl, arylsulfonyl, linear or branched C¿1?-C¿20? alkylsulfonyl, and di-(C¿1?-C¿10? or C¿1?-C¿20? alkoxyalkyl)phosphonyl and X includes O, S, NH, or the function R?8¿X is selected from aziridino, mono- or poly- substituted linear or branched C¿1?-C¿20? alkyl aziridino, pyrrolidino, mono- or poly- substituted linear or branched C¿1?-C¿20? alkyo pyrrolidino, piperidino, mono- or poly- substituted linear or branched C¿1?-C¿20? alkyl piperidino, morpholino, mono- or poly- substituted linear or branched C¿1?-C¿20? alkyl morpholino, thiomorpholino, mono- or poly- substituted linear or branched C¿1?-C¿20? alkyl thiomorpholino, indolino, mono- or poly- substituted linear or branched C¿1?-C¿20? alkyl indolino, piperazino, mono- or poly- substituted linear or branched C¿1?-C¿20? alkyl piperazino, linear or branched C¿1?-C¿20?$i(N)-alkylpiperazino, linear or branched C¿1?-C¿20?$i(N)-hydroxyalkylpiperazino, $i(N)-phenylpiperazino, $i(N)-aryliperazino, homopiperidino, mono- or poly- substituted linear or branched C¿1?-C¿20? alkyl homopiperidino, $i(N)-indolinyl, $i(N)-1,2,3,4-tetrahydroquinolinyl, $i(N)-1,2,3,4,4a-hexahydrocarbazolyl. The compounds may be combined with polymeric host material such as plastic or glass or make a sunglass Lens, an Ophthalmic Lens or a window. The compounds may also be included in an ink or a fuel

  • Intense Colouring Photochromic 2H-Naphtho[1,2-b]pyrans and Heterocyclic Pyrans
    1998
    Co-Authors: Clarke, David A., Heron B. Mark, Gabbutt, Christopher D., Hepworth, John D., Partington, Steven M., Corns, Stephen N., James Robinson Ltd
    Abstract:

    A naphtho [1,2-$i(b)] pyran of general formula (I), wherein one or both of R?1¿ and R?2¿ is a 4-aminoaryl group; R?5¿ is selected from linear or branched C¿1?-C¿10? alkyl, C¿1?-C¿20? cycloalkyl, C¿1?-C¿20? bicycloalkyl, C¿1?-C¿20? polycycloalkyl, linear or branched C¿1?-C¿10? haloalkyl, linear or branched C¿1?-C¿10? perhaloalkyl, linear or branched C¿1?-C¿10? perhaloalkenyl, linear or branched C¿1?-C¿10? alkenyl, C¿1?-C¿10? alkynyl, linear or branched C¿1?-C¿10? alkoxy, linear or branched C¿1?-C¿10? alkylthio, linear or branched C¿1?-C¿10? alkoxy (linear or branched C¿1?-C¿10? alkyl), linear or branched C¿1?-C¿10? hydroxyalkyl, linear or branched C¿1?-C¿10? aminoalkyl, aryl, phenyl, heteroaryl, halogen, nitrile, nitro, amino, linear or branched C¿1?-C¿20? alkoxycarbonyl, hydroxyl, formyl, acetyl, amido, C¿1?-C¿5? alkylamido, C¿1?-C¿5? dialkylamido, aroyl, benzoyl, alkyl C¿1?-C¿5? amino, dialkyl C¿1?-C¿5? amino, arylamino, diarylamino, aryl C¿1?-C¿5? alkylamino and cyclicamino groups; arylsulfinyl, arylsulfanyl, arylsulfonyl, linear or branched C¿1?-C¿10? alkylsulfonyl, P(O)(O-C¿1?-C¿10? alkyl)¿2? or is the alkenyl function (II), wherein R?11¿ and/or R?12¿ and/or R?13¿ is hydrogen or is as defined for R?5¿, and R?3¿, R?4¿ and R?6¿-R?10¿ are each hydrogen or as defined R?1¿, R?2¿ or R?5¿. The compounds may be combined with a polymeric host material such as a plastic or a glass to make a sunglass Lens, an Ophthalmic Lens or a window

  • Neutral Colouring Photochromic 2H-Naphtho[1,2-b]pyrans and Heterocyclic Pyrans and Their Use
    1998
    Co-Authors: Clarke, David A., Heron B. Mark, Gabbutt, Christopher D., Hepworth, John D., Partington, Steven M., Corns, Stephen N., James Robinson Ltd
    Abstract:

    A naphtho[1,2-$i(b)]pyran of general formula (I) wherein R?1¿ and R?2¿ are each selected from unsubstituted, mono-, di- or polysubstituted aryl groups, phenyl and naphthyl and heteroaryl groups. R?5¿ is selected from linear or branched C¿1?-C¿10? alkyl, C¿1?-C¿20? cycloalkyl, C¿1?-C¿20? bicycloalkyl, C¿1?-C¿20? polycycloalkyl, linear or branched C¿1?-C¿10? haloalkyl, linear or branched C¿1?-C¿10? perhaloalkyl, linear or branched C¿1?-C¿10? perhaloalkenyl, linear or branched C¿1?-C¿10? alkenyl, C¿1?-C¿10? alkynyl, linear or branched C¿1?-C¿10? alkoxy, linear or branched C¿1?-C¿10? alkylthio, linear or branched C¿1?-C¿10? alkoxy (linear or branched C¿1?-C¿10? alkyl), linear or branched C¿1?-C¿10? hydroxyalkyl, linear or branched C¿1?-C¿10? aminoalkyl, aryl, phenyl, heteroaryl, halogen, nitrile, nitro, amino, linear or branched C¿1?-C¿20? alkoxycarbonyl, hydroxyl, formyl, acetyl, amido, C¿1?-C¿5? alkyl amido, C¿1?-C¿5? dialkylamido, aroyl, benzoyl, alkyl C¿1?-C¿5? amino, dialkyl C¿1?-C¿5? amino, arylamino, diarylamino, aryl C¿1?-C¿5? alkylamino and cyclicamino groups, arylsulfinyl, arylsulfanyl, arylsulfonyl, linear or branched C¿1?-C¿10? alkylsulfonyl, P(O)(O-C¿1?-C¿10? alkyl)¿2? or is an alkenyl function of general formula (a) wherein R?11¿ and/or R?12¿ and/or R?13¿ is hydrogen or R?5¿, R?3¿, R?4¿, R?6¿, R?8¿ and R?10¿ are each hydrogen, R?1¿, R?2¿ or R?5¿; and R?7¿ and/or R?9¿ is hydrogen or an amino group provided that R?7¿ and R?9¿ are not both hydrogen. The compounds may be combined with a polymeric host material such as plastic or glass to make a sunglass Lens, an Ophthalmic Lens or a window

Tracey Hanley - One of the best experts on this subject based on the ideXlab platform.

  • the generic enhancement of photochromic dye switching speeds in a rigid polymer matrix
    Nature Materials, 2005
    Co-Authors: Georgina K. Such, Richard A. Evans, Tracey Hanley, Melissa A Skidmore, Thomas P Davis
    Abstract:

    The switching or isomerization speed of photochromic dyes in a rigid polymeric matrix (such as an Ophthalmic Lens) is generally significantly slower than that observed in the mobile environment of a solution. Here we describe that the attachment of flexible oligomers having a low glass-transition temperature—such as poly(dimethylsiloxane)—to photochromic dyes greatly increases their switching speeds in a rigid polymer matrix. The greatest impact was observed in the thermal fade parameters T1/2 and T3/4—the times it takes for the optical density to reduce by half and three quarters of the initial optical density of the coloured state—which were reduced by 40–95% and 60–99% respectively for spirooxazines, chromenes and an azo dye in a host polymer with a glass-transition temperature of 120 °C. The method does not alter the electronic nature of the dyes but simply protects them from the host matrix and provides greater molecular mobility for the switching process. In addition to Ophthalmic Lenses, the generic nature of the method may find further utility in data recording or optical switching.