Papers by mark schaerlaekens
Journal of Physical Chemistry B, May 1, 2002
We have prepared new photorefractive methacrylate copolymers functionalized with a highly polar b... more We have prepared new photorefractive methacrylate copolymers functionalized with a highly polar bifunctional chromophore. The photorefractive response was studied by ellipsometry, four-wave mixing, and two-beam coupling and is compared to that of polymers and polymer composites studied previously. The polymer could be sensitized with C 60 for operation at the writing wavelength of 780 nm, which results in an improved grating build-up time. At this wavelength, we have observed overmodulation of the internal diffraction efficiency at an applied bias field of 43 V/µm. We have found evidence for the formation of aggregates and phase separation in the copolymers.
Proceedings of SPIE, Jan 17, 2002
ABSTRACT We have studied the photorefractive properties of three different polymer types. A first... more ABSTRACT We have studied the photorefractive properties of three different polymer types. A first class were (2,4,7-trinitro- 9-fluorenylidene)malononitrile sensitized poly(N- vinylcarbazole)/N-ethylcarbazole polymer composites doped with dyes of varying polarity. The performance was optimized, and at an applied field of 59 Volt/micrometer, we have observed complete internal diffraction and a gain coefficient of 167 cm-1. A photorefractive two-beam coupling novelty filter was constructed with such a polymer. The response of these composites was compared to that of polymethacrylates functionalized with carbazole, an internal plasticizer and different chromophores. The best results were obtained in a third polymer type, where only a bifunctional chromophore was attached to the polymer backbone.
Proceedings of SPIE, Dec 10, 2003
ABSTRACT We report on the synthesis, the molecular properties and an evaluation of the photorefra... more ABSTRACT We report on the synthesis, the molecular properties and an evaluation of the photorefractive performance of different types of polymer composites. Samples were C60 and (2, 4, 7-trinitro-9-fluorenylidene)malonitrile (TNFDM) sensitized and characterized by four-wave mixing and two-beam coupling experiments at 680 and 780 nm. In a first type of composite, new synthesized N-arylated carbazoles were used as bifunctional chromophores to demonstrate the importance of the relative orientation of dipole moment and polarizability tensor on the Figure-of-Merit (FOM) of photorefractive experiments. Investigations were performed on mixed inorganic/organic nanocomposites to extend the photosensitivity of the samples to longer wavelengths, photoconductivity at 980 nm was studied on PbS colloids/PVK samples. Finally, a fully functionalized photorefractive polymer was synthesized and analyzed by four-wave mixing and two beam coupling experiments. The polymer showed a strange oscillating behavior in diffraction efficiency and gain. Thus far the temporally oscillation couldn"t be explained properly.
Chemical Physics, Mar 1, 2002
ABSTRACT We report on the synthesis and the molecular properties of new N-arylated carbazole deri... more ABSTRACT We report on the synthesis and the molecular properties of new N-arylated carbazole derivatives that are used as bifunctional chromophores in photorefractive (PR) polymer composites. The C–N bond of the N-aryl carbazole chromophore was formed directly by a nucleophilic aromatic substitution and Ullmann type coupling of carbazole with aryl halides. We performed calculations on the molecular conformation, the magnitude of the dipole moment and the linear polarizability tensor and their relative orientation. The PR performance of the chromophores, doped in an inert polymer host matrix and in a carbazole matrix, with C60 as sensitizer, was evaluated using four-wave mixing experiments and photoconductivity measurements at 680 nm. The impact of the relative orientation of dipole moment and polarizability tensor on the Figure-Of-Merit (FOM) of photorefractive experiments was clearly demonstrated.
Journal of Materials Chemistry, Feb 15, 2002
ABSTRACT A series of photorefractive polymethacrylates, containing a Disperse Red type chromophor... more ABSTRACT A series of photorefractive polymethacrylates, containing a Disperse Red type chromophore and carbazole as charge transport agent with various spacer lengths, was synthesized and characterized. The photorefractive effect of these materials was studied by four-wave mixing and two beam-coupling at 780 nm after sensitization with 1 wt% TNFM. We have found a gain coefficient of Γ = 140 cm−1 at an applied electric field of 60 V µm−1 and complete internal diffraction at an applied electric field of 52 V µm−1. For fully functionalized photorefractive polymers, these values rank among the highest reported up to date.
Springer eBooks, 2009
Page 77. Chapter 3 Innovative Textile Materials, Stiffening Procedures and Fabric-Joining Methods... more Page 77. Chapter 3 Innovative Textile Materials, Stiffening Procedures and Fabric-Joining Methods 3.1 Shape-Memory Textile Polymer Fibres Yan Ji, Mark Schaerlaekens, Eugene M. Terentjev Abstract The use of shape-memory ...
Nonlinear Optical Transmission Processes and Organic Photorefractive Materials, 2002
ABSTRACT We have studied the photorefractive properties of three different polymer types. A first... more ABSTRACT We have studied the photorefractive properties of three different polymer types. A first class were (2,4,7-trinitro- 9-fluorenylidene)malononitrile sensitized poly(N- vinylcarbazole)/N-ethylcarbazole polymer composites doped with dyes of varying polarity. The performance was optimized, and at an applied field of 59 Volt/micrometer, we have observed complete internal diffraction and a gain coefficient of 167 cm-1. A photorefractive two-beam coupling novelty filter was constructed with such a polymer. The response of these composites was compared to that of polymethacrylates functionalized with carbazole, an internal plasticizer and different chromophores. The best results were obtained in a third polymer type, where only a bifunctional chromophore was attached to the polymer backbone.
The Journal of Physical Chemistry B, 2002
We have prepared new photorefractive methacrylate copolymers functionalized with a highly polar b... more We have prepared new photorefractive methacrylate copolymers functionalized with a highly polar bifunctional chromophore. The photorefractive response was studied by ellipsometry, four-wave mixing, and two-beam coupling and is compared to that of polymers and polymer composites studied previously. The polymer could be sensitized with C 60 for operation at the writing wavelength of 780 nm, which results in an improved grating build-up time. At this wavelength, we have observed overmodulation of the internal diffraction efficiency at an applied bias field of 43 V/µm. We have found evidence for the formation of aggregates and phase separation in the copolymers.
Chemical Physics, 2002
ABSTRACT We report on the synthesis and the molecular properties of new N-arylated carbazole deri... more ABSTRACT We report on the synthesis and the molecular properties of new N-arylated carbazole derivatives that are used as bifunctional chromophores in photorefractive (PR) polymer composites. The C–N bond of the N-aryl carbazole chromophore was formed directly by a nucleophilic aromatic substitution and Ullmann type coupling of carbazole with aryl halides. We performed calculations on the molecular conformation, the magnitude of the dipole moment and the linear polarizability tensor and their relative orientation. The PR performance of the chromophores, doped in an inert polymer host matrix and in a carbazole matrix, with C60 as sensitizer, was evaluated using four-wave mixing experiments and photoconductivity measurements at 680 nm. The impact of the relative orientation of dipole moment and polarizability tensor on the Figure-Of-Merit (FOM) of photorefractive experiments was clearly demonstrated.
Journal of Materials Chemistry, 2002
ABSTRACT A series of photorefractive polymethacrylates, containing a Disperse Red type chromophor... more ABSTRACT A series of photorefractive polymethacrylates, containing a Disperse Red type chromophore and carbazole as charge transport agent with various spacer lengths, was synthesized and characterized. The photorefractive effect of these materials was studied by four-wave mixing and two beam-coupling at 780 nm after sensitization with 1 wt% TNFM. We have found a gain coefficient of Γ = 140 cm−1 at an applied electric field of 60 V µm−1 and complete internal diffraction at an applied electric field of 52 V µm−1. For fully functionalized photorefractive polymers, these values rank among the highest reported up to date.
We have studied the photorefractive properties of three different polymer types. A first class we... more We have studied the photorefractive properties of three different polymer types. A first class were (2/4/7-trinitro-9-fluorenylidene)rnalononitrile sensitized poly(N-vinylcarbazole)/N-ethylcarbazole polymer composites doped with dyes of varying polarity. The performance was optimized, and at an applied field of 59 Volt/micrometer, we have observed complete internal diffraction and a gain coefficient of 167 cm-1. A photorefractive two-beam coupling novelty filter was constructed with such a polymer. The response of these composites was compared to that of polymethacrylates functionalized with carbazole, an internal plasticizer and different chromophores. The best results were obtained in a third polymer type, where only a bifunctional chromophore was attached to the polymer backbone.
… Clothing Production Into a …, 2009
Page 77. Chapter 3 Innovative Textile Materials, Stiffening Procedures and Fabric-Joining Methods... more Page 77. Chapter 3 Innovative Textile Materials, Stiffening Procedures and Fabric-Joining Methods 3.1 Shape-Memory Textile Polymer Fibres Yan Ji, Mark Schaerlaekens, Eugene M. Terentjev Abstract The use of shape-memory ...
Organic Holographic Materials and Applications, 2003
ABSTRACT We report on the synthesis, the molecular properties and an evaluation of the photorefra... more ABSTRACT We report on the synthesis, the molecular properties and an evaluation of the photorefractive performance of different types of polymer composites. Samples were C60 and (2, 4, 7-trinitro-9-fluorenylidene)malonitrile (TNFDM) sensitized and characterized by four-wave mixing and two-beam coupling experiments at 680 and 780 nm. In a first type of composite, new synthesized N-arylated carbazoles were used as bifunctional chromophores to demonstrate the importance of the relative orientation of dipole moment and polarizability tensor on the Figure-of-Merit (FOM) of photorefractive experiments. Investigations were performed on mixed inorganic/organic nanocomposites to extend the photosensitivity of the samples to longer wavelengths, photoconductivity at 980 nm was studied on PbS colloids/PVK samples. Finally, a fully functionalized photorefractive polymer was synthesized and analyzed by four-wave mixing and two beam coupling experiments. The polymer showed a strange oscillating behavior in diffraction efficiency and gain. Thus far the temporally oscillation couldn"t be explained properly.
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Papers by mark schaerlaekens