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Guy Koeckelberghs - One of the best experts on this subject based on the ideXlab platform.

  • Unraveling the Supramolecular Organization Mechanism of Chiral Star-Shaped Poly(3-alkylthiophene)
    Macromolecules, 2020
    Co-Authors: Michèle Moris, Marie-paule Van Den Eede, Guy Koeckelberghs, Olivier Deschaume, Carmen Bartic, Koen Clays, Stijn Van Cleuvenbergen, Thierry Verbiest
    Abstract:

    The Supramolecular Organization of star-shaped polythiophenes was investigated in a solvent/nonsolvent system and upon cooling. Both systems yield entirely different Supramolecular aggregates. Clas...

  • Controlled Synthesis and Supramolecular Organization of Conjugated Star-Shaped Polymers
    Macromolecules, 2018
    Co-Authors: Marie-paule Van Den Eede, Julien De Winter, Pascal Gerbaux, Joan Teyssandier, Steven De Feyter, Cédric Van Goethem, Ivo F.j. Vankelecom, Guy Koeckelberghs
    Abstract:

    Through the incorporation of chiral and achiral poly(3-alkylthiophenes) (P3ATs) into a star-shaped system, a well-defined Supramolecular Organization is obtained lacking the unfavorable linear lamellar structure typically obtained for P3AT. Through the combination of a controlled chain-growth polymerization and efficient postpolymerization and click reactions, well-defined star-shaped P3ATs with a low dispersity of 1.1 were obtained. The combination of UV–vis, circular dichroism (CD), atomic force microscopy (AFM), and transmission electron microscopy (TEM) measurements showed the formation of a strong (chiral) Supramolecular Organization into fibers, different and stronger than those obtained with the linear P3ATs. The fact that the width of the fibers is in good agreement with the width of a single star-shaped P3AT excludes the formation of a linear lamellar structure. Furthermore, the particular Supramolecular Organization of the star-shaped polymers, which appears thanks to the precision polymer synth...

  • Synthesis and Supramolecular Organization of chiral poly(thiophene)–magnetite hybrid nanoparticles
    Polymer Chemistry, 2018
    Co-Authors: Ward Ceunen, Julien De Winter, Pascal Gerbaux, Steven De Feyter, Thierry Verbiest, Annelien Van Oosten, Rick Vleugels, Guy Koeckelberghs
    Abstract:

    In this study, poly((S)-3-(3′,7′-dimethyloctyl)thiophene) is synthesized via KCTCP, using a catechol-based external Ni-initiator. After characterization, the polymer's catechol functionality is deprotected and coupled with magnetite nanoparticles and the Supramolecular Organization is studied using UV/Vis, CD, AFM and Faraday measurements. We conclude that no long range Supramolecular ordering is present in the hybrid material and that only interchain interactions between polymer chains attached on different nanoparticles are present. Also the effect of the new initiator and the branched monomer side chain on the controlled character of the KCTCP is investigated. It is found that a methyl group on the 3-position of the monomer sidechain already affects the controlled character of the polymerization. Also, a mechanism for the observed effects of the branched monomer and the new catechol-based initiator on the controlled character of the polymerization is proposed.

  • Influence of the Supramolecular Organization on the Magnetic Properties of Poly(3-alkylthiophene)s in Their Neutral State
    Macromolecules, 2011
    Co-Authors: Steven Vandeleene, Thierry Verbiest, Mihaela Jivanescu, Andre Stesmans, J. Cuppens, Margriet J. Van Bael, Guy Koeckelberghs
    Abstract:

    The influence of the Supramolecular behavior on the magnetic properties of head-to-tail coupled poly(3-alkylthiophene)s (P3AT) is reported. Samples with a different molar mass were prepared, and differences in their behavior were illustrated by UV–vis and CD spectroscopy. In addition, tuning of the Supramolecular Organization was also accomplished by applying thermal annealing. ESR spectroscopy was performed on powder samples. From the line features, information on the nature of the unpaired spins, the mobility, and the Supramolecular order of the sample was derived. These spins are paramagnetic. SQUID magnetometry, in contrast, shows for all samples a ferromagnetic behavior at 5 K and superparamagnetism at 300 K. The coercivity does not depend on the degree of Supramolecular order but is inherent to the molecular structure and, related to this, the π-interactions. The saturation magnetization, on the contrary, seems to be mainly influenced by the fraction of planarized polymer chains.

Arun K. Nandi - One of the best experts on this subject based on the ideXlab platform.

  • Supramolecular Organization of Poly(vinylidene fluoride)−Camphor Sulfonic Acid Blends: Giant Spherulites
    Langmuir, 2003
    Co-Authors: M. Habibur Rahman, Arun K. Nandi
    Abstract:

    A gradual change in morphology of poly(vinylidene fluoride)-camphor sulfonic acid (PVF 2 -CSA) blend from compact spherulites of PVF 2 to open spherulites and finally to giant spherulites with increasing CSA concentration in the blend is observed when viewed in optical microscopy. An X-ray study indicates the presence of two types of lamella, viz., (i) Supramolecularly organized lamella of the PVF 2 -CSA system and (ii) lamella of pure PVF 2 crystal in the blends. A differential scanning calorimetry study reveals that the crystallization of the Supramolecular organized structure is a slow process Supramolecular Organization of PVF 2 -CSA blends produces giant spherulites at CSA-rich compositions. The giant spherulites contain a fibrillar network structure with the piezoelectric form of PVF 2 and may find application as a sensor material.

  • Thermoreversible Supramolecular Organization in Poly(vinylidene fluoride)–Dodecyl Benzene Sulfonic Acid Blends
    Macromolecular Chemistry and Physics, 2003
    Co-Authors: M. Habibur Rahman, Sudip Malik, Arun K. Nandi
    Abstract:

    Blends of poly(vinylidene fluoride) (PVF 2 ) and dodecyl benzene sulfonic acid (DBSA) were found to phase separate in the melt state from hot-stage polarizing optical microscopy and differential scanning calorimetry (DSC). Both these studies also indicated the formation of a reversible mesomorphic order in the DBSA-rich phase of the blends. Scanning electron microscopy (SEM) showed a fibrillar network morphology of the DBSA-rich phase. Wide-angle X-ray diffraction (WAXD) revealed the formation of a lamellar structure in the blends corresponding to a long period of 26 A. The mesomorphic nature of the blends is believed to arise from the Supramolecular Organization of the surfactant molecules within the lamella. Thermal study indicated that the Supramolecularly organized complex is the VF 2 monomer unit:DBSA ≈ 4:1, and the enthalpy of complexation is ~723 J mol −1 .

A. V. Kazak - One of the best experts on this subject based on the ideXlab platform.

  • Supramolecular Organization and optical properties of BODIPY derivatives in Langmuir–Schaefer films
    New Journal of Chemistry, 2020
    Co-Authors: Yu. S. Marfin, A. V. Kazak, Sergey D. Usoltsev, Olga S. Vodyanova, N. E. Novikova, I. A. Verin, Evgeniy V. Rumyantsev, I. V. Kholodkov, D. A. Merkushev
    Abstract:

    Four BODIPY (boron-dipyrrin) dyes with various condensed aromatic moieties (phenyl, naphthyl, anthryl and pyrenyl) as 8-substituents were chosen and their Supramolecular Organization and properties in Langmuir–Schaefer (LS) films with different numbers of layers were investigated. The spectral characteristics of the dyes in LS-films and solution and the structure of the films were examined. The BODIPY substituent structure influences the character of the intermolecular interactions of the dyes in LS-films. The phenyl-substituted compound was found to form excimers with a long wavelength fluorescence peak at 582 nm upon the layer number increase, yet only minor bathochromic shifts of the peak position were observed for the films of the other investigated compounds. Moreover, unlike in liquid solutions, the dyes in LS-films were not found to exhibit solvatochromic properties. All of the compounds (except anthryl-substituted) were found to retain fluorescence in solid films. Transfer of films from a floating monolayer was indicated by further material analysis: the measured average periodicity corresponds to a single-layer structure of BODIPY molecules located parallel to the surface with an interplanar distance of d = 0.3 nm. The obtained results broaden the prospects of BODIPY based thin film material applications, denoting versatile modification routes leading to increased fluorescence, tunable excimer formation equilibrium and crystallinity.

  • Influence of molecular structure peculiarities of phthalocyanine derivatives on their Supramolecular Organization and properties in the bulk and thin films
    Phase Transitions, 2014
    Co-Authors: Nadezhda V. Usol’tseva, V. V. Sotsky, A. V. Kazak, S. G. Yudin, Ivan Yu. Luk'yanov, A. I. Smirnova, G. P. Shaposhnikov, N. E. Galanin
    Abstract:

    In order to study the influence of molecular structure peculiarities on Supramolecular Organization and properties in the bulk and thin films of discotic mesogens six new mix-substituted phthalocyanine derivatives with 3,6-dioctyloxyphthalonitrile and 3,4,5,6-tetrachlorophthalonitrile fragments were synthesized. Temperatures of phase transitions, types of mesophase and their dependence on molecule structure, chemical nature, position and ratio of different substituents as well as presence of holmium in the metal complexes were analyzed. The behavior of the studied molecules on the boundary between water and air was investigated and the peculiarity of Supramolecular Organization in floating layers as well as in thin films was determined. Quenching of luminescence in solutions of the studied compounds in the presence of fullerene C60 was determined, thus giving prospects for application of these compounds as sensors for fullerene microquantities.

  • Supramolecular Organization of meso-substituted derivatives of tetraphenylporphine in thin films
    Journal of Surface Investigation. X-ray Synchrotron and Neutron Techniques, 2013
    Co-Authors: A. V. Kazak, Nadezhda V. Usol’tseva, S. G. Yudin, Vladimir V. Volkov
    Abstract:

    Films of meso-substituted derivatives of tetraphenylporphine substituted in the paraor ortho-positions of the phenyl rings with alkoxy groups (-OC4H9 or -OC16H33) and films of their metal complexes are prepared using the Langmuir-Schaefer (LS) method. The effect of the molecular structure on the Supramolecular Organization of thin films is determined. The films are obtained by transferring layers of the compounds from the surface of the water onto silicon substrates using the Langmuir-Schaefer technique. The structures of the one-component LS films of the investigated compounds are studied by the small-angle X-ray scattering method, and also the lattice periodicities are calculated. The Supramolecular Organization of the meso-substituted tetraphenylporphine derivatives is modeled and refined by means of the X-ray diffraction method. When Ni or Cu serve as chelating metal, it is found that the macrocycle-macrocycle interaction is so large that it leads to violation of the molecular linearity, i.e., the lateral substituents are folded toward the macrocycle, reducing the area occupied by the structural units.

  • Influence of meso-substituted tetraphenylporphyrin derivatives structure on their Supramolecular Organization in floating layers and Langmuir-Blodgett films.
    Langmuir, 2012
    Co-Authors: A. V. Kazak, V. V. Sotsky, Nadezhda V. Usol’tseva, S. G. Yudin, Alexandr S. Semeikin
    Abstract:

    To study the influence of structure peculiarities of porphyrin derivatives on their Supramolecular Organization in thin films, 15 new meso-substituted tetraphenylporphyrin derivatives and their metal complexes with substituents (−OC4H9 or −OC16H33) in para or ortho positions were studied. The films of the studied compounds were obtained by the Langmuir–Schaefer method. The behavior of porphyrin derivatives at the water–air interface was analyzed, and the conformity of the influence of molecular structure on Supramolecular Organization in floating layers and Langmuir–Blodgett films was defined. The absorption of these films over a wide spectral range was analyzed. The Supramolecular Organization of meso-substituted tetraphenylporphyrin derivatives was modeled and specified with the help of X-ray diffraction analysis. It was determined that the formation of monomolecular layers is typical for the compounds with short lateral substituents or without substituents. Tetraphenylporphyrins with extensive substitu...

  • Influence of porphine derivatives molecular structure on their Supramolecular Organization in floating layers and Langmuir-Blodgett films
    2012
    Co-Authors: A. V. Kazak, V. V. Sotsky, Nadezhda V. Usol’tseva, Kirill A. Dembo, S. G. Yudin, Alexandr S. Semeikin
    Abstract:

    In order to study the influence of molecular structure features on their Supramolecular Organization in the floating layers and thin films 15 new meso-substituted tetraphenylporphine derivatives and their metal complexes with substitution in para- or ortho-positions (-OC 4 H 9 or -OC 16 H 33 ) were investigated. Methods full-scale modeling of Supramolecular Organization of the compounds in the floating layers was performed using molecular mechanics and molecular dynamics. The dependence of supra-molecular Organization of floating layers and thin films from the structure of the porphines was studied.

Alexandr S. Semeikin - One of the best experts on this subject based on the ideXlab platform.

Thierry Verbiest - One of the best experts on this subject based on the ideXlab platform.

  • Unraveling the Supramolecular Organization Mechanism of Chiral Star-Shaped Poly(3-alkylthiophene)
    Macromolecules, 2020
    Co-Authors: Michèle Moris, Marie-paule Van Den Eede, Guy Koeckelberghs, Olivier Deschaume, Carmen Bartic, Koen Clays, Stijn Van Cleuvenbergen, Thierry Verbiest
    Abstract:

    The Supramolecular Organization of star-shaped polythiophenes was investigated in a solvent/nonsolvent system and upon cooling. Both systems yield entirely different Supramolecular aggregates. Clas...

  • Synthesis and Supramolecular Organization of chiral poly(thiophene)–magnetite hybrid nanoparticles
    Polymer Chemistry, 2018
    Co-Authors: Ward Ceunen, Julien De Winter, Pascal Gerbaux, Steven De Feyter, Thierry Verbiest, Annelien Van Oosten, Rick Vleugels, Guy Koeckelberghs
    Abstract:

    In this study, poly((S)-3-(3′,7′-dimethyloctyl)thiophene) is synthesized via KCTCP, using a catechol-based external Ni-initiator. After characterization, the polymer's catechol functionality is deprotected and coupled with magnetite nanoparticles and the Supramolecular Organization is studied using UV/Vis, CD, AFM and Faraday measurements. We conclude that no long range Supramolecular ordering is present in the hybrid material and that only interchain interactions between polymer chains attached on different nanoparticles are present. Also the effect of the new initiator and the branched monomer side chain on the controlled character of the KCTCP is investigated. It is found that a methyl group on the 3-position of the monomer sidechain already affects the controlled character of the polymerization. Also, a mechanism for the observed effects of the branched monomer and the new catechol-based initiator on the controlled character of the polymerization is proposed.

  • Influence of the Supramolecular Organization on the Magnetic Properties of Poly(3-alkylthiophene)s in Their Neutral State
    Macromolecules, 2011
    Co-Authors: Steven Vandeleene, Thierry Verbiest, Mihaela Jivanescu, Andre Stesmans, J. Cuppens, Margriet J. Van Bael, Guy Koeckelberghs
    Abstract:

    The influence of the Supramolecular behavior on the magnetic properties of head-to-tail coupled poly(3-alkylthiophene)s (P3AT) is reported. Samples with a different molar mass were prepared, and differences in their behavior were illustrated by UV–vis and CD spectroscopy. In addition, tuning of the Supramolecular Organization was also accomplished by applying thermal annealing. ESR spectroscopy was performed on powder samples. From the line features, information on the nature of the unpaired spins, the mobility, and the Supramolecular order of the sample was derived. These spins are paramagnetic. SQUID magnetometry, in contrast, shows for all samples a ferromagnetic behavior at 5 K and superparamagnetism at 300 K. The coercivity does not depend on the degree of Supramolecular order but is inherent to the molecular structure and, related to this, the π-interactions. The saturation magnetization, on the contrary, seems to be mainly influenced by the fraction of planarized polymer chains.