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Mathieu Surin - One of the best experts on this subject based on the ideXlab platform.

  • regioregular poly 3 hexylthiophene poly e caprolactone block copolymers controlled synthesis Microscopic Morphology and charge transport properties
    Organic Electronics, 2010
    Co-Authors: Mathieu Surin, Roberto Lazzaroni, Philippe Leclere, Olivier Coulembier, Khoa Tran, Julien De Winter, Pascal Gerbaux, Philippe Dubois
    Abstract:

    Abstract In this paper, we describe the design and characterization of regioregular poly(3-hexylthiophene)-poly(e-caprolactone) di- and tri-block copolymers (RRP3HT- b -PCL and PCL- b -RRP3HT- b -PCL). The well-controlled synthesis of (di)hydroxyl-terminated RRP3HT makes possible to design block copolymer structures with a narrow molecular weight distribution. The Microscopic Morphology is investigated by atomic force microscopy, which reveals self-assembled fibrillar structures with the RRP3HT nanoribbons separated by narrow domains of insulating PCL. The charge transport properties are characterized in thin films field-effect transistors, and comparison between the devices performances is carried out in view of the nanoscale Morphology within the transistor channel.

  • synthesis characterization and comparative ofet behaviour of indenofluorene bithiophene and terthiophene alternating copolymers
    Synthetic Metals, 2010
    Co-Authors: Prashant Sonar, Roberto Lazzaroni, Luke Oldridge, Andrew C Grimsdale, Klaus Mullen, Mathieu Surin, Philippe Leclere, Jason Pinto, Laylay Chua, Henning Sirringhaus
    Abstract:

    The synthesis of alternating copolymers of tetraalkylindenofluorene with bithiophene and terthiophene using Suzuki polycondensation route is reported. We report on the optical and electrochemical properties of these copolymers. AFM analysis of the Microscopic Morphology of thin deposits showed that the copolymer with terthiophene units produced the more ordered films, with well-defined fibrillar structures, resulting from highly-regular dense packing due to strong π-π interchain interactions, in contrast to the amorphous bithiophene copolymer. Upon testing these materials in FETs the terthienyl copolymers displayed the higher charge mobilities among the studied compounds, with values of over 10-4 cm2 V-1 s-1 being obtained.

  • relationship between the Microscopic Morphology and the charge transport properties in poly 3 hexylthiophene field effect transistors
    Journal of Applied Physics, 2006
    Co-Authors: Mathieu Surin, Ph. Leclère, Roberto Lazzaroni, Jonathan D Yuen, Guangming Wang, D Moses, A J Heeger, Shinuk Cho, Kwanghee Lee
    Abstract:

    We fabricate field-effect transistors (FETs) by depositing a regioregular poly(3-hexylthiophene) (RR-P3HT) active layer via different preparation methods. The solvent used in the polymer film deposition and the deposition technique determine the film microstructure, which ranges from amorphous or granular films to a well-defined fibrillar texture. The crystalline ordering of RR-P3HT into fibrillar structures appears to lead to optimal FET performances, suggesting that fibrils act as efficient “conduits” for the charge carrier transport. Treating the silicon oxide gate insulator with hexamethyldisilazane enhanced the FET performance.

  • Microscopic Morphology of polyfluorene poly ethylene oxide block copolymers influence of the block ratio
    Advanced Functional Materials, 2004
    Co-Authors: Mathieu Surin, Roberto Lazzaroni, Andrew C Grimsdale, Klaus Mullen, Dirk Marsitzky, Philippe Leclere
    Abstract:

    In this paper, we describe the synthesis and characterization of poly(9,9′-dioctylfluorene)–poly(ethylene oxide) (PF-PEO) block copolymers with different block ratio and molecular architectures (diblock or triblock copolymers). Tapping-mode atomic force microscopy is used to investigate the relationship between the molecular structure and the Microscopic Morphology of thin deposits. Copolymers with a low average volume ratio of PEO (fEO from 0.1 to 0.3) exhibit a well-defined organization into nanoribbons. A model of chain packing is proposed; these structures arise from the interplay of π–π interactions between conjugated PF segments and the interactions of PEO with the mica substrate surface. For copolymers with higher average volume ratio of PEO (fEO > 0.4), the organized structures disappear and lead to untextured aggregates, probably because long-range, regular π–π stacking of the segments can no longer take place. We also observe that the nature of the solvent from which deposits are grown and the substrate polarity have a strong impact on the Microscopic Morphology.

  • correlation between the Microscopic Morphology and the solid state photoluminescence properties in fluorene based polymers and copolymers
    Chemistry of Materials, 2004
    Co-Authors: Mathieu Surin, Roberto Lazzaroni, Andrew C Grimsdale, Klaus Mullen, Dirk Marsitzky, Emmanuelle Hennebicq, Christophe Ego, Jeanluc Bredas, Philippe Leclere
    Abstract:

    The Microscopic Morphology of a series of substituted fluorene-based conjugated polymers and copolymers are analyzed with tapping-mode atomic force microscopy. Different structures are observed depending on the nature of the substituents. Thin deposits of polyfluorenes substituted with linear alkyl groups are made of long fibrils, with lateral dimensions on the order of a few nanometers; polymers with branched alkyl or aromatic substituents form homogeneous, featureless films. To understand how polymer chains pack into these structures, comparisons are made with molecular modeling calculations; the simulation results highlight the dependence between intermolecular π−π interactions and steric hindrance among substituents:  linear alkyl substituents allow for a close packing of the conjugated chains into very long, regular π−π stacks, in contrast to the bulkier substituents. A strong correlation is established between the degree of order in the thin deposits and the solid-state photoluminescence spectra; a ...

Roberto Lazzaroni - One of the best experts on this subject based on the ideXlab platform.

  • regioregular poly 3 hexylthiophene poly e caprolactone block copolymers controlled synthesis Microscopic Morphology and charge transport properties
    Organic Electronics, 2010
    Co-Authors: Mathieu Surin, Roberto Lazzaroni, Philippe Leclere, Olivier Coulembier, Khoa Tran, Julien De Winter, Pascal Gerbaux, Philippe Dubois
    Abstract:

    Abstract In this paper, we describe the design and characterization of regioregular poly(3-hexylthiophene)-poly(e-caprolactone) di- and tri-block copolymers (RRP3HT- b -PCL and PCL- b -RRP3HT- b -PCL). The well-controlled synthesis of (di)hydroxyl-terminated RRP3HT makes possible to design block copolymer structures with a narrow molecular weight distribution. The Microscopic Morphology is investigated by atomic force microscopy, which reveals self-assembled fibrillar structures with the RRP3HT nanoribbons separated by narrow domains of insulating PCL. The charge transport properties are characterized in thin films field-effect transistors, and comparison between the devices performances is carried out in view of the nanoscale Morphology within the transistor channel.

  • synthesis characterization and comparative ofet behaviour of indenofluorene bithiophene and terthiophene alternating copolymers
    Synthetic Metals, 2010
    Co-Authors: Prashant Sonar, Roberto Lazzaroni, Luke Oldridge, Andrew C Grimsdale, Klaus Mullen, Mathieu Surin, Philippe Leclere, Jason Pinto, Laylay Chua, Henning Sirringhaus
    Abstract:

    The synthesis of alternating copolymers of tetraalkylindenofluorene with bithiophene and terthiophene using Suzuki polycondensation route is reported. We report on the optical and electrochemical properties of these copolymers. AFM analysis of the Microscopic Morphology of thin deposits showed that the copolymer with terthiophene units produced the more ordered films, with well-defined fibrillar structures, resulting from highly-regular dense packing due to strong π-π interchain interactions, in contrast to the amorphous bithiophene copolymer. Upon testing these materials in FETs the terthienyl copolymers displayed the higher charge mobilities among the studied compounds, with values of over 10-4 cm2 V-1 s-1 being obtained.

  • Microscopic Morphology of chlorinated polyethylene based nanocomposites synthesized from poly e caprolactone clay masterbatches
    Langmuir, 2008
    Co-Authors: Patrick Brocorens, Michael Alexandre, Samira Benali, Cédric Broekaert, Fabien Monteverde, Hans Miltner, Bruno Van Mele, Philippe Dubois, Roberto Lazzaroni
    Abstract:

    Chlorinated polyethylene (CPE) nanocomposites were synthesized by melt blending clay-rich/poly(e-caprolactone) (PCL) masterbatches to CPE matrices. The masterbatches were prepared following two synthetic routes:  either PCL is melt-blended to the clay or it is grafted to the clay platelets by in situ polymerization. The Microscopic Morphology of the nanocomposites was characterized by X-ray diffraction, atomic force microscopy, transmission electron microscopy, and modulated temperature differential scanning calorimetry. When using free PCL, intercalated composites are formed, with clay aggregates that can have micrometric dimensions and a Morphology similar to that of the talc particles used as fillers in commercial CPE. PCL crystallizes as long lamellae dispersed in the polymer matrix. When using grafted PCL, the nanocomposite is intercalated/exfoliated, and the clay stacks are small and homogeneously dispersed. PCL crystallizes as lamellae and smaller crystals, which are localized along the clay layers...

  • relationship between the Microscopic Morphology and the charge transport properties in poly 3 hexylthiophene field effect transistors
    Journal of Applied Physics, 2006
    Co-Authors: Mathieu Surin, Ph. Leclère, Roberto Lazzaroni, Jonathan D Yuen, Guangming Wang, D Moses, A J Heeger, Shinuk Cho, Kwanghee Lee
    Abstract:

    We fabricate field-effect transistors (FETs) by depositing a regioregular poly(3-hexylthiophene) (RR-P3HT) active layer via different preparation methods. The solvent used in the polymer film deposition and the deposition technique determine the film microstructure, which ranges from amorphous or granular films to a well-defined fibrillar texture. The crystalline ordering of RR-P3HT into fibrillar structures appears to lead to optimal FET performances, suggesting that fibrils act as efficient “conduits” for the charge carrier transport. Treating the silicon oxide gate insulator with hexamethyldisilazane enhanced the FET performance.

  • Microscopic Morphology of polyfluorene poly ethylene oxide block copolymers influence of the block ratio
    Advanced Functional Materials, 2004
    Co-Authors: Mathieu Surin, Roberto Lazzaroni, Andrew C Grimsdale, Klaus Mullen, Dirk Marsitzky, Philippe Leclere
    Abstract:

    In this paper, we describe the synthesis and characterization of poly(9,9′-dioctylfluorene)–poly(ethylene oxide) (PF-PEO) block copolymers with different block ratio and molecular architectures (diblock or triblock copolymers). Tapping-mode atomic force microscopy is used to investigate the relationship between the molecular structure and the Microscopic Morphology of thin deposits. Copolymers with a low average volume ratio of PEO (fEO from 0.1 to 0.3) exhibit a well-defined organization into nanoribbons. A model of chain packing is proposed; these structures arise from the interplay of π–π interactions between conjugated PF segments and the interactions of PEO with the mica substrate surface. For copolymers with higher average volume ratio of PEO (fEO > 0.4), the organized structures disappear and lead to untextured aggregates, probably because long-range, regular π–π stacking of the segments can no longer take place. We also observe that the nature of the solvent from which deposits are grown and the substrate polarity have a strong impact on the Microscopic Morphology.

I O Agbakwuru - One of the best experts on this subject based on the ideXlab platform.

  • the mandibular salivary gland Microscopic Morphology of the adult african giant pouched rat cricetomys gambianus waterhouse 1840
    European journal of anatomy, 2014
    Co-Authors: Ekele Ikpegbu, U C Nlebedum, O Nnadozie, I O Agbakwuru
    Abstract:

    The mandibular salivary gland Microscopic Morphology of the adult African giant pouched rat was investigated. This study was carried out to provide the basic histology of this organ in the giant pouched rat, as there is dearth of information of its Microscopic architecture in available literature. This is of the most importance, as the possible use of this species of rodent is considered as a future laboratory animal instead of the Wistar rat because of its bigger size; also, for purposes of domestication and use as a ready source of animal protein. Hence the need to understand the digestive biology to help animal nutritionist in feed formulation. Histology revealed the presence of both serous and mucus secretory acini. Some mucous cells presented serous demilunes. Myoeithelial cells were seen around secretory cells and the intercalated ducts. The serous gland region with more relatively profuse intralobular ducts was larger in size than the mucus gland region. The intralobular ducts of intercalated and striated ducts were lined by simple cuboidal and simple columnar cells respectively. The excretory duct was lined by stratified cuboidal cells. The large serous glandular region reflects the need for more enzymic action in the oral cavity, while the mucus glands will help produce mucin that will lubricate the digestive tract. This study for the first time documents the normal histology of the mandibular salivary gland in this species, hence filling a gap that will help further investigative research, especially the role of myoepithelial cells in secretory glands tumors.

  • the submandibular salivary gland Microscopic Morphology of the adult african giant pouched rat cricetomys gambianus waterhouse 1840
    Iranian Journal of Veterinary Medicine, 2013
    Co-Authors: Ekele Ikpegbu, U C Nlebedum, O Nnadozie, I O Agbakwuru
    Abstract:

    BACKGROUND: In the present study, the submandibular salivary gland Microscopic Morphology of the adult African giant pouched rat was investigated. This study was carried out to provide the basic histology of this organ in the giant pouched rat, to accompany the dearth of information of its Microscopic architecture in the available literature. This becomes of even higher importance when considering the possible use of this species of rodent as a future laboratory animal to replace the Winster rat, because of its bigger size and the possibility of domesticating the giant pouched rat as a ready source of animal protein. In addition, the need to understand the digestive biology to help animal nutritionists in feeding formulation may also be achieved. The histology revealed the presence of both serous and mucus secretory acini. Some mucus cells showed serous demilumes. The myoeithelial cells were seen around the secretory cells and the intercalated ducts. The serous gland region with more relatively profuse intralobular ducts was larger in size than the mucus gland region. The intralobular ducts of intercalated and striated ducts were lined by simple cuboidal and simple columnar cells, respectively. The excretory duct was lined by the stratified cuboidal cells. The large serous glandular region reflects need for more enzymic action in the oral cavity, while the mucus glands will help produce mucin that will lubricate the digestive tract. This study, for the first time documents the normal histology of submandibular salivary gland in this species, hence filling the knowledge gap that will help further research especially on the role of myoepihelial cells in the secretory glands tumours.

Ekele Ikpegbu - One of the best experts on this subject based on the ideXlab platform.

  • the mandibular salivary gland Microscopic Morphology of the adult african giant pouched rat cricetomys gambianus waterhouse 1840
    European journal of anatomy, 2014
    Co-Authors: Ekele Ikpegbu, U C Nlebedum, O Nnadozie, I O Agbakwuru
    Abstract:

    The mandibular salivary gland Microscopic Morphology of the adult African giant pouched rat was investigated. This study was carried out to provide the basic histology of this organ in the giant pouched rat, as there is dearth of information of its Microscopic architecture in available literature. This is of the most importance, as the possible use of this species of rodent is considered as a future laboratory animal instead of the Wistar rat because of its bigger size; also, for purposes of domestication and use as a ready source of animal protein. Hence the need to understand the digestive biology to help animal nutritionist in feed formulation. Histology revealed the presence of both serous and mucus secretory acini. Some mucous cells presented serous demilunes. Myoeithelial cells were seen around secretory cells and the intercalated ducts. The serous gland region with more relatively profuse intralobular ducts was larger in size than the mucus gland region. The intralobular ducts of intercalated and striated ducts were lined by simple cuboidal and simple columnar cells respectively. The excretory duct was lined by stratified cuboidal cells. The large serous glandular region reflects the need for more enzymic action in the oral cavity, while the mucus glands will help produce mucin that will lubricate the digestive tract. This study for the first time documents the normal histology of the mandibular salivary gland in this species, hence filling a gap that will help further investigative research, especially the role of myoepithelial cells in secretory glands tumors.

  • the submandibular salivary gland Microscopic Morphology of the adult african giant pouched rat cricetomys gambianus waterhouse 1840
    Iranian Journal of Veterinary Medicine, 2013
    Co-Authors: Ekele Ikpegbu, U C Nlebedum, O Nnadozie, I O Agbakwuru
    Abstract:

    BACKGROUND: In the present study, the submandibular salivary gland Microscopic Morphology of the adult African giant pouched rat was investigated. This study was carried out to provide the basic histology of this organ in the giant pouched rat, to accompany the dearth of information of its Microscopic architecture in the available literature. This becomes of even higher importance when considering the possible use of this species of rodent as a future laboratory animal to replace the Winster rat, because of its bigger size and the possibility of domesticating the giant pouched rat as a ready source of animal protein. In addition, the need to understand the digestive biology to help animal nutritionists in feeding formulation may also be achieved. The histology revealed the presence of both serous and mucus secretory acini. Some mucus cells showed serous demilumes. The myoeithelial cells were seen around the secretory cells and the intercalated ducts. The serous gland region with more relatively profuse intralobular ducts was larger in size than the mucus gland region. The intralobular ducts of intercalated and striated ducts were lined by simple cuboidal and simple columnar cells, respectively. The excretory duct was lined by the stratified cuboidal cells. The large serous glandular region reflects need for more enzymic action in the oral cavity, while the mucus glands will help produce mucin that will lubricate the digestive tract. This study, for the first time documents the normal histology of submandibular salivary gland in this species, hence filling the knowledge gap that will help further research especially on the role of myoepihelial cells in the secretory glands tumours.

Philippe Leclere - One of the best experts on this subject based on the ideXlab platform.

  • regioregular poly 3 hexylthiophene poly e caprolactone block copolymers controlled synthesis Microscopic Morphology and charge transport properties
    Organic Electronics, 2010
    Co-Authors: Mathieu Surin, Roberto Lazzaroni, Philippe Leclere, Olivier Coulembier, Khoa Tran, Julien De Winter, Pascal Gerbaux, Philippe Dubois
    Abstract:

    Abstract In this paper, we describe the design and characterization of regioregular poly(3-hexylthiophene)-poly(e-caprolactone) di- and tri-block copolymers (RRP3HT- b -PCL and PCL- b -RRP3HT- b -PCL). The well-controlled synthesis of (di)hydroxyl-terminated RRP3HT makes possible to design block copolymer structures with a narrow molecular weight distribution. The Microscopic Morphology is investigated by atomic force microscopy, which reveals self-assembled fibrillar structures with the RRP3HT nanoribbons separated by narrow domains of insulating PCL. The charge transport properties are characterized in thin films field-effect transistors, and comparison between the devices performances is carried out in view of the nanoscale Morphology within the transistor channel.

  • synthesis characterization and comparative ofet behaviour of indenofluorene bithiophene and terthiophene alternating copolymers
    Synthetic Metals, 2010
    Co-Authors: Prashant Sonar, Roberto Lazzaroni, Luke Oldridge, Andrew C Grimsdale, Klaus Mullen, Mathieu Surin, Philippe Leclere, Jason Pinto, Laylay Chua, Henning Sirringhaus
    Abstract:

    The synthesis of alternating copolymers of tetraalkylindenofluorene with bithiophene and terthiophene using Suzuki polycondensation route is reported. We report on the optical and electrochemical properties of these copolymers. AFM analysis of the Microscopic Morphology of thin deposits showed that the copolymer with terthiophene units produced the more ordered films, with well-defined fibrillar structures, resulting from highly-regular dense packing due to strong π-π interchain interactions, in contrast to the amorphous bithiophene copolymer. Upon testing these materials in FETs the terthienyl copolymers displayed the higher charge mobilities among the studied compounds, with values of over 10-4 cm2 V-1 s-1 being obtained.

  • Microscopic Morphology of polyfluorene poly ethylene oxide block copolymers influence of the block ratio
    Advanced Functional Materials, 2004
    Co-Authors: Mathieu Surin, Roberto Lazzaroni, Andrew C Grimsdale, Klaus Mullen, Dirk Marsitzky, Philippe Leclere
    Abstract:

    In this paper, we describe the synthesis and characterization of poly(9,9′-dioctylfluorene)–poly(ethylene oxide) (PF-PEO) block copolymers with different block ratio and molecular architectures (diblock or triblock copolymers). Tapping-mode atomic force microscopy is used to investigate the relationship between the molecular structure and the Microscopic Morphology of thin deposits. Copolymers with a low average volume ratio of PEO (fEO from 0.1 to 0.3) exhibit a well-defined organization into nanoribbons. A model of chain packing is proposed; these structures arise from the interplay of π–π interactions between conjugated PF segments and the interactions of PEO with the mica substrate surface. For copolymers with higher average volume ratio of PEO (fEO > 0.4), the organized structures disappear and lead to untextured aggregates, probably because long-range, regular π–π stacking of the segments can no longer take place. We also observe that the nature of the solvent from which deposits are grown and the substrate polarity have a strong impact on the Microscopic Morphology.

  • correlation between the Microscopic Morphology and the solid state photoluminescence properties in fluorene based polymers and copolymers
    Chemistry of Materials, 2004
    Co-Authors: Mathieu Surin, Roberto Lazzaroni, Andrew C Grimsdale, Klaus Mullen, Dirk Marsitzky, Emmanuelle Hennebicq, Christophe Ego, Jeanluc Bredas, Philippe Leclere
    Abstract:

    The Microscopic Morphology of a series of substituted fluorene-based conjugated polymers and copolymers are analyzed with tapping-mode atomic force microscopy. Different structures are observed depending on the nature of the substituents. Thin deposits of polyfluorenes substituted with linear alkyl groups are made of long fibrils, with lateral dimensions on the order of a few nanometers; polymers with branched alkyl or aromatic substituents form homogeneous, featureless films. To understand how polymer chains pack into these structures, comparisons are made with molecular modeling calculations; the simulation results highlight the dependence between intermolecular π−π interactions and steric hindrance among substituents:  linear alkyl substituents allow for a close packing of the conjugated chains into very long, regular π−π stacks, in contrast to the bulkier substituents. A strong correlation is established between the degree of order in the thin deposits and the solid-state photoluminescence spectra; a ...

  • correlation between molecular structure Microscopic Morphology and optical propertiesof poly tetraalkylindenofluorene s
    Advanced Functional Materials, 2002
    Co-Authors: Andrew C Grimsdale, Roberto Lazzaroni, Philippe Leclere, J D Mackenzie, C Murphy, Sepas Setayesh, Carlos Silva, Richard Henry Friend, Klaus Mullen
    Abstract:

    The emission properties of polyindenofluorenes with various proportions of straight- and branched-chain alkyl substituents have been compared. The polymer with straight octyl substituents shows green emission due to formation of aggregates, while the polymer with branched 2-ethylhexyl substituents shows blue emission. Studies of the film Morphology show the presence of ordered structures due to π-stacking of the polymer chains for the octyl-substituted polymer, whereas the polymer with branched side-chains shows no such order. Copolymers show intermediate behavior. A clear correlation is established between the degree of straight-chain alkyl substitution, the formation of ordered structures in the films, and the amount of long wavelength emission in the solid-state spectra.