The Experts below are selected from a list of 318 Experts worldwide ranked by ideXlab platform

Atsushi Takahara - One of the best experts on this subject based on the ideXlab platform.

  • Imogolite Polymer Nanocomposites
    Developments in Clay Science, 2020
    Co-Authors: Wei Ma, Yuji Higaki, Atsushi Takahara
    Abstract:

    Imogolite is a naturally occurring aluminosilicate nanotube consisting of a single-walled with a composition of (OH)3Al2O3SiOH, with Al–OH and Si–OH groups distributed on the external and internal surfaces of the tube wall, respectively. The recent progress in surface modification of Imogolite utilizing specific interaction between Al–OH and phosphonic acid is reported in this chapter, and the preparation procedures of novel Imogolite-based polymer nanocomposites are introduced.

  • structure and properties of hybrid film fabricated by spin assisted layer by layer assembly of sacran and Imogolite nanotubes
    Langmuir, 2020
    Co-Authors: Linlin Li, Atsushi Takahara, Akihiko Takada, Shigenori Fujikawa, Miho Ariyoshi, Kousuke Igata, Maiko K Okajima, Tatsuo Kaneko
    Abstract:

    A free-standing (biomacomolecule/synthetic inorganic nanotubes) hybrid film was fabricated through an alternative layer-by-layer (LBL) assembly of sacran and Imogolite nanotubes. Sacran is a natural polysaccharide extracted from the cyanobacterium Aphanothece sacrum, while Imogolite is a natural tubular aluminosilicate clay found in volcano ash. The hybrid film thickness increased linearly with the number of the bilayers, because of the interaction between the negatively charged surface of sacran and the positively charged surface of Imogolite. UV–vis spectroscopy indicated that the LBL film exhibited good transparency. The surface morphology of the LBL film was smooth in the micrometer scale; many Imogolite nanotubes were adsorbed onto the sacran layer, while no Imogolite clusters were observed. Furthermore, the structure, stability, gas permeability, and mechanical properties of the LBL films were investigated.

  • organic inorganic hybrid thin films fabricated by layer by layer assembly of the phosphorylated cellulose nanocrystal and Imogolite nanotubes
    Langmuir, 2018
    Co-Authors: Linlin Li, Yuji Higaki, Kazutaka Kamitani, Atsushi Takahara
    Abstract:

    Phosphorylated cellulose nanocrystal (P-CNC)/Imogolite nanotube (natural aluminosilicate nanotube) hybrid thin films were fabricated by spin-assisted layer-by-layer assembly. Phosphorylation of CNC with diammonium hydrogen phosphate ((NH4)2HPO4) was carried out to introduce phosphate groups on the CNC surface for enhanced interaction with Imogolite. Structure of the P-CNC/Imogolite thin film was characterized by atomic force microscopy, scanning electron microscopy, X-ray diffraction (XRD), and grazing incidence wide-angle XRD. The film thickness increased linearly with the increment of the P-CNC/Imogolite bilayer. Benefitting from the strong affinity between the phosphate group of the P-CNC and the Al–OH group of Imogolite, the P-CNC/Imogolite thin films were quite stable in water within a wide range of pH values, compared with the deterioration of the CNC/Imogolite film under same soaking conditions.

  • application of Imogolite clay nanotubes in organic inorganic nanohybrid materials
    Journal of Materials Chemistry, 2012
    Co-Authors: Hideyuki Otsuka, Atsushi Takahara
    Abstract:

    The unique one dimensional structure and the positively charged external surface are the driving forces for Imogolite clay nanotubes emerging as one of the most promising nano building blocks for various hybrid materials. This paper reviews the utility of Imogolite in organic–inorganic nanohybrids, including polymer–Imogolite nanocomposites and Imogolite based hybrid hydrogels. Several effective approaches for dispersing Imogolite down to small-sized bundles or even individual nanotubes in polymer matrices, including both hydrophobic and hydrophilic polymers, are introduced. The application of Imogolite for the direct gel formation of biomolecules is also introduced.

  • Application of Imogolite clay nanotubes in organic–inorganic nanohybrid materials
    Journal of Materials Chemistry, 2012
    Co-Authors: Wei Ma, Hideyuki Otsuka, Atsushi Takahara
    Abstract:

    The unique one dimensional structure and the positively charged external surface are the driving forces for Imogolite clay nanotubes emerging as one of the most promising nano building blocks for various hybrid materials. This paper reviews the utility of Imogolite in organic–inorganic nanohybrids, including polymer–Imogolite nanocomposites and Imogolite based hybrid hydrogels. Several effective approaches for dispersing Imogolite down to small-sized bundles or even individual nanotubes in polymer matrices, including both hydrophobic and hydrophilic polymers, are introduced. The application of Imogolite for the direct gel formation of biomolecules is also introduced.

Antoine Thill - One of the best experts on this subject based on the ideXlab platform.

  • Imogolites as a tool for evaluating the hazard of HARN
    Mineralogical Magazine, 2020
    Co-Authors: Clément Levard, Antoine Thill, Perrine Chaurand, Jérôme Rose, Melanie Auffan, Armand Masion, Emmanuel Doelsch, Olivier Proux, Jean-yves Bottero
    Abstract:

    Since the discovery of carbon nanotubes (NTs), there has been great interest in the synthesis and characterization of similar shaped structures like inorganic nanotubes, nanorods, or nanowires. Imogolites (Al2SiO3 (OH)4) are natural aluminosilicate single wall nanotubes. To date, only Ge-Al Imogolite analogues have been successfully synthesized 100 times more concentrated than Si-Al Imogolites. The growth mechanisms of Imogolite-like aluminogermanate nanotubes were examined using a combination of local- (XAS at the Ge-Kedge and 27Al NMR) and semilocal scale techniques (in situ SAXS). A model is proposed for the precursors of the nanotubular structure and consist in rooftileshaped particles, up to 5 nm in size, with ca. 26% of Ge vacancies and varying curvatures. These precursors assemble to form short nanotubes/nanorings observed during the aging process. The final products are most likely obtained by an edge-edge assembly of these short nanotube segments. Two structures are revealed by SAXS: at 0.25M of Al the Al-Ge Imogolite are double-walled NTs whereas at 0.5 M single-walled NTs are obtained. First tests to reveal cyto and genotoxicity on various vertebrates cells (human fibroblasts and CHO-K1) are interesting. They show a genotoxicity for concentrations from 8 10-5 g/L and effects decreasing from proto-Imogolite to long tube. (Texte integral)

  • Reactivity and toxicity of Imogolite nanotubes
    2020
    Co-Authors: Clément Levard, Antoine Thill, Perrine Chaurand, Jérôme Rose, Melanie Auffan, Armand Masion, Emmanuel Doelsch, Jean-yves Bottero
    Abstract:

    Since the discovery of carbon nanotubes (NTs), there has been great interest in the synthesis and characterization of similar shaped structures like inorganic nanotubes, nanorods, or nanowires. Imogolites (Al2SiO3(OH)4) are natural aluminosilicate single wall nanotubes. To date, only Ge-Al Imogolite analogues have been successfully synthesized 100 times more concentrated than Si-Al Imogolites. The growth mechanisms of Imogolite-like aluminogermanate nanotubes were examined using a combination of local- (XAS at the Ge-Kedge and 27Al NMR) and semilocal scale techniques (in situ SAXS). A model is proposed for the precursors of the nanotubular structure and consist in rooftile-shaped particles, up to 5 nm in size, with ca. 26% of Ge vacancies and varying curvatures. These precursors assemble to form short nanotubes/nanorings observed during the aging process. The final products are most likely obtained by an edge-edge assembly of these short nanotube segments. Two structures are revealed by SAXS: at 0.25M of Al the Al-Ge Imogolite are double-walled NTs whereas at 0.5 M single-walled NTs are obtained. First tests to reveal cyto and genotoxicity on various vertebrates cells (human fibroblasts and CHO-K1) are interesting. They show a genotoxicity for concentrations from 8 10-5 g/L and effects decreasing from proto-Imogolite to long tubes. (Texte integral)

  • Mechanisms of formation and reactivity of Imogolite types material
    2020
    Co-Authors: Jérôme Rose, Antoine Thill, Perrine Chaurand, Clément Levard, Armand Masion, Emmanuel Doelsch, Isabelle Basile-doelsch, Jean-yves Bottero
    Abstract:

    Reactivity of nanopar8cles represents a central issue for many laboratories around the world. Among many supported efforts the control of the morphology of nanopar8cles is mo8vated by the fact that morphology strongly influence the proper8es of the final products. Among the vast family of available nanopar8cles, Imogolite is a clay nanotube for which perfect control of the diameter is possible. Imogolites were first observed in volcanic soils[1]. They are natural aluminosilicate nanotubes having the general formula (OH)3Al2O3SiOH with a 2 nm external diameter and up to micrometers in length. The impressive monodispersity in Imogolite nanotube diameter has mo8vated research on their forma8on mechanism. Synthesis protocols to produce Imogolite were quickly developed. Farmer et al. were the first to obtain synthe8c Imogolite using low concentra8ons of AlCl3 and SiO 2 monomers as star8ng materials (millimolar concentra8ons of the reagents) [2]. However, the produc8on of large amount of Imogolite or Imogolite type materials remained challenging for long 8me. We will present our most recent results concerning the possibility to produce Imogolite type materials from highly concentrated stock solu8ons. We will also detail the possibility to form double wall Al- Ge nanotubes and the different stages of their forma8on [3-7]. We will then detail the surface reac8vity of these nanotubes toward metals at he lab scale as well as in natural soil. (Resume d'auteur)

  • Alignment of Ge-Imogolite nanotubes in isomalt with tunable inter-tube distances
    RSC Advances, 2020
    Co-Authors: Clément Levard, Antoine Thill, Armand Masion, Cyprien Mauroy, Vladimir Vidal, Astrid Avellan, Andrea P. C. Campos, Jérôme Rose
    Abstract:

    This study shows the almost perfect alignment of inorganic nanotubes (Ge-Imogolite) within polyol filaments. Alignment was obtained by simply cooling a Ge-Imogolite-polyol mixture under mechanical stress. Additionally, inter-tube distances in the plane normal to the filaments can be tuned by simply varying the weight fraction of Imogolite in the starting solution. The ease of the alignment protocol will stimulate interest for testing new applications which require a good control of the pore density and morphology (periodicity, and high monodispersity of the pore size distribution).

  • dual internal functionalization of Imogolite nanotubes as evidenced by optical properties of nile red
    Applied Clay Science, 2019
    Co-Authors: Pierre Picot, Thibaud Coradin, Frederic Gobeaux, Antoine Thill
    Abstract:

    Abstract Hybrid Imogolites have been prepared by combining methyltrimethoxysilane with various organosilanes (Si-R) to obtain nanotubes with a bi-functional internal cavity. With an initial doping ratio Si-R/Si of 5%, nanotubes remain the major product in the samples and their diameter is not modified compared to pristine methyl Imogolite (Imo–CH3). The nanotube wall's internal polarity and reactivity is significantly changed as evidenced by using a solvatochromic dye (Nile red). This research opens many possibilities to bring selectivity to the internal cavity or to manipulate the properties of trapped organic molecules.

Daewon Sohn - One of the best experts on this subject based on the ideXlab platform.

  • structural response of Imogolite poly acrylic acid hydrogel under deformation
    Macromolecules, 2016
    Co-Authors: Jaehyoung Ko, Taegyu Shin, Daewon Sohn
    Abstract:

    The structures of Imogolite–poly(acrylic acid) hydrogels were investigated using small-angle X-ray scattering (SAXS) and small-angle neutron scattering (SANS) to determine the effects of particle concentration and the magnitude of deformation. The Imogolite–poly(acrylic acid) hydrogel was synthesized by using γ-ray radiation as a nanocomposite gel with chemical bonds between the particles and polymers. The SAXS measurements revealed that the Imogolite network was composed of particle overlaps. Under deformation, the gel structure was rearranged to increase the dimensionality of the network, forming a relaxed structure of overlaps by changing the orientation of the Imogolite. The structural response of the deformed gel depended on the Imogolite concentration, which influenced the changes in dimensionality of the network and the number of overlaps. The SANS patterns indicated that the polymers wrapped the Imogolite aggregates, allowing polymers to follow the Imogolite behavior. These observations demonstrat...

  • Strain Energy and Structural Property of Methyl Substituted Imogolite
    Molecular Crystals and Liquid Crystals, 2014
    Co-Authors: Geunyeong Park, Daewon Sohn
    Abstract:

    Aluminosilicate mineral, Imogolite, with chemical composition [(OH)3Al2O3SiOH] has high monodispersity of diameter originated by the arrangements of inner hydroxyl (OH) groups that induced the strain energy minimum due to hydrogen bond networks. We have successfully synthesized substituted Imogolite with methyl groups (Me-imo) instead of inner hydroxyl groups. While Imogolite prefers zigzag chirality, Me-imo prefers armchair chirality which was confirmed by the simulation and the x-ray diffraction (XRD) pattern. Me-imo has larger specific surface area and less hydrogen bond contribution than that of Imogolite, which was confirmed by the Barrett-Joyner-Halenda (BJH) pore size distribution.

  • preparation of an Imogolite poly acrylic acid hybrid gel
    Journal of Colloid and Interface Science, 2013
    Co-Authors: Daewon Sohn
    Abstract:

    Abstract Many efforts in the field of hydrogels have been focused toward increasing the mechanical strength of the gel using inorganic materials. In this study, we synthesized a hydrogel that has excellent mechanical properties using surface-modified inorganic nanofibers composed of Imogolite (Al2SiO3(OH)4), which is a hydrated aluminum silicate that has a hollow tube structure. Gamma ray radiation generates peroxide radicals on the nanofibers (Imogolite), resulting in an additive free hybrid hydrogel. Structural optimization was carried out by changing the composition of Imogolite and poly(acrylic acid). Chemical bonding between the nanofiber and the polymer was simulated by a cluster model and characterized by wide area Raman spectroscopy. The results indicate that Imogolite embedded in a polymer matrix can align along the direction of an elongational force, as confirmed by small angle X-ray scattering (SAXS).

  • Preparation of an Imogolite/poly(acrylic acid) hybrid gel
    Journal of Colloid and Interface Science, 2013
    Co-Authors: Daewon Sohn
    Abstract:

    Abstract Many efforts in the field of hydrogels have been focused toward increasing the mechanical strength of the gel using inorganic materials. In this study, we synthesized a hydrogel that has excellent mechanical properties using surface-modified inorganic nanofibers composed of Imogolite (Al2SiO3(OH)4), which is a hydrated aluminum silicate that has a hollow tube structure. Gamma ray radiation generates peroxide radicals on the nanofibers (Imogolite), resulting in an additive free hybrid hydrogel. Structural optimization was carried out by changing the composition of Imogolite and poly(acrylic acid). Chemical bonding between the nanofiber and the polymer was simulated by a cluster model and characterized by wide area Raman spectroscopy. The results indicate that Imogolite embedded in a polymer matrix can align along the direction of an elongational force, as confirmed by small angle X-ray scattering (SAXS).

  • origin of the strain energy minimum in Imogolite nanotubes
    Journal of Physical Chemistry C, 2011
    Co-Authors: Young Cheol Choi, Sang Gil Youm, Daewon Sohn
    Abstract:

    We have systematically analyzed the structure of Imogolite and their energetics, to understand the physics governing control over Imogolite nanotube diameter and strain energy. In this work, we have presented evidence that the arrangements of inner and outer hydroxyl (OH) groups, that is hydrogen bond (HB) networks, play an important role in the formation of Imogolite nanotubes and their structural stability. The outer HB significantly affects the Al−O distances and generates two different structures. Even though the relaxation of inner and outer Al−O and Si−O bond distances is the driving force for tubular Imogolite formation, we show that the origin of the strain energy minimum, that is high monodispersity of diameter in Imogolite nanotubes, is the inner HB networks. The preference for zigzag chirality and the formation mechanism of tubular Imogolite also can be understood based on HB networks. Therefore, we present that a comprehensive understanding of the origin of high monodispersity of diameter and ...

Hideyuki Otsuka - One of the best experts on this subject based on the ideXlab platform.

  • application of Imogolite clay nanotubes in organic inorganic nanohybrid materials
    Journal of Materials Chemistry, 2012
    Co-Authors: Hideyuki Otsuka, Atsushi Takahara
    Abstract:

    The unique one dimensional structure and the positively charged external surface are the driving forces for Imogolite clay nanotubes emerging as one of the most promising nano building blocks for various hybrid materials. This paper reviews the utility of Imogolite in organic–inorganic nanohybrids, including polymer–Imogolite nanocomposites and Imogolite based hybrid hydrogels. Several effective approaches for dispersing Imogolite down to small-sized bundles or even individual nanotubes in polymer matrices, including both hydrophobic and hydrophilic polymers, are introduced. The application of Imogolite for the direct gel formation of biomolecules is also introduced.

  • Application of Imogolite clay nanotubes in organic–inorganic nanohybrid materials
    Journal of Materials Chemistry, 2012
    Co-Authors: Wei Ma, Hideyuki Otsuka, Atsushi Takahara
    Abstract:

    The unique one dimensional structure and the positively charged external surface are the driving forces for Imogolite clay nanotubes emerging as one of the most promising nano building blocks for various hybrid materials. This paper reviews the utility of Imogolite in organic–inorganic nanohybrids, including polymer–Imogolite nanocomposites and Imogolite based hybrid hydrogels. Several effective approaches for dispersing Imogolite down to small-sized bundles or even individual nanotubes in polymer matrices, including both hydrophobic and hydrophilic polymers, are introduced. The application of Imogolite for the direct gel formation of biomolecules is also introduced.

  • preparation and characterization of Imogolite dna hybrid hydrogels
    Biomacromolecules, 2012
    Co-Authors: Nattha Jiravanichanun, Kazuya Yamamoto, Hideyuki Otsuka, Kenichi Kato, Shin Horiuchi, Atsushi Takahara
    Abstract:

    Imogolite is one of the clay minerals contained in volcanic ash soils. The novel hybrid hydrogels were prepared from Imogolite nanofibers and DNA by utilizing strong interaction between the aluminol groups on Imogolite surface and phosphate groups of DNA. The hybrid hydrogels of Imogolite and DNA were prepared in various feed ratios, and their physicochemical properties and molecular aggregation states were investigated in both dispersion and gel states. The maximum DNA content in the hybrid gels was shown in equivalent molar ratio of Imogolite and DNA. The physical properties of the hybrid gels were changed by varying DNA blend ratios. In the dispersion state, the hybrid gels showed a fibrous structure of Imogolite, whereas a continuous network structure was observed in pure Imogolite, indicating that the hybrid with DNA enhanced the dispersion of Imogolite. In the gel state, DNA and Imogolite nanofibers formed a 3D network structure.

  • Preparation and Characterization of Imogolite/DNA Hybrid Hydrogels
    Biomacromolecules, 2011
    Co-Authors: Nattha Jiravanichanun, Kazuya Yamamoto, Hideyuki Otsuka, Kenichi Kato, Shin Horiuchi, Atsushi Takahara
    Abstract:

    Imogolite is one of the clay minerals contained in volcanic ash soils. The novel hybrid hydrogels were prepared from Imogolite nanofibers and DNA by utilizing strong interaction between the aluminol groups on Imogolite surface and phosphate groups of DNA. The hybrid hydrogels of Imogolite and DNA were prepared in various feed ratios, and their physicochemical properties and molecular aggregation states were investigated in both dispersion and gel states. The maximum DNA content in the hybrid gels was shown in equivalent molar ratio of Imogolite and DNA. The physical properties of the hybrid gels were changed by varying DNA blend ratios. In the dispersion state, the hybrid gels showed a fibrous structure of Imogolite, whereas a continuous network structure was observed in pure Imogolite, indicating that the hybrid with DNA enhanced the dispersion of Imogolite. In the gel state, DNA and Imogolite nanofibers formed a 3D network structure.

  • preparation and properties of pvc pmma g Imogolite nanohybrid via surface initiated radical polymerization
    Polymer, 2011
    Co-Authors: Hideyuki Otsuka, Atsushi Takahara
    Abstract:

    Abstract Poly(methyl methacrylate) (PMMA) grafted Imogolite clay nanotubes (PMMA-g-Imogolite) were prepared through activators regenerated by electron transfer for atom transfer radical polymerization (ARGET ATRP) by developing a water soluble amphiphilic ATRP initiator, which carries both an initiator moiety and a surface-attachable phosphate group. Poly(vinyl chloride)/PMMA-g-Imogolite nanohybrid was prepared by using this PMMA grafted Imogolite. The structure and properties of the prepared nanohybrid were characterized by differential scanning calorimetry (DSC), transmission electron microscopy (TEM), scanning electron microscopy (SEM), and tensile test. DSC and TEM results indicate that well-dispersed PMMA-g-Imogolite dominates in the nanohybrid, in spite of some Imogolite rich regions. SEM observation of the fracture surfaces and the fractured films reveals that the interfacial adhesion between PMMA grafted Imogolite and the matrix may be weak or strong with respect to the cohesive energy of the poly(vinyl chloride) (PVC) matrix, depending on the environmental temperature. In liquid nitrogen or at room temperature, the interfacial adhesion between PMMA grafted Imogolite and the matrix is weaker, while at 90 °C, is stronger than the cohesion of the PVC matrix. In accordance with the interfacial performance, the nanohybrid shows inferior tensile performance at room temperature; whereas, superior tensile performance at 90 °C compared with the pristine PVC.

Jérôme Rose - One of the best experts on this subject based on the ideXlab platform.

  • Imogolites as a tool for evaluating the hazard of HARN
    Mineralogical Magazine, 2020
    Co-Authors: Clément Levard, Antoine Thill, Perrine Chaurand, Jérôme Rose, Melanie Auffan, Armand Masion, Emmanuel Doelsch, Olivier Proux, Jean-yves Bottero
    Abstract:

    Since the discovery of carbon nanotubes (NTs), there has been great interest in the synthesis and characterization of similar shaped structures like inorganic nanotubes, nanorods, or nanowires. Imogolites (Al2SiO3 (OH)4) are natural aluminosilicate single wall nanotubes. To date, only Ge-Al Imogolite analogues have been successfully synthesized 100 times more concentrated than Si-Al Imogolites. The growth mechanisms of Imogolite-like aluminogermanate nanotubes were examined using a combination of local- (XAS at the Ge-Kedge and 27Al NMR) and semilocal scale techniques (in situ SAXS). A model is proposed for the precursors of the nanotubular structure and consist in rooftileshaped particles, up to 5 nm in size, with ca. 26% of Ge vacancies and varying curvatures. These precursors assemble to form short nanotubes/nanorings observed during the aging process. The final products are most likely obtained by an edge-edge assembly of these short nanotube segments. Two structures are revealed by SAXS: at 0.25M of Al the Al-Ge Imogolite are double-walled NTs whereas at 0.5 M single-walled NTs are obtained. First tests to reveal cyto and genotoxicity on various vertebrates cells (human fibroblasts and CHO-K1) are interesting. They show a genotoxicity for concentrations from 8 10-5 g/L and effects decreasing from proto-Imogolite to long tube. (Texte integral)

  • Reactivity and toxicity of Imogolite nanotubes
    2020
    Co-Authors: Clément Levard, Antoine Thill, Perrine Chaurand, Jérôme Rose, Melanie Auffan, Armand Masion, Emmanuel Doelsch, Jean-yves Bottero
    Abstract:

    Since the discovery of carbon nanotubes (NTs), there has been great interest in the synthesis and characterization of similar shaped structures like inorganic nanotubes, nanorods, or nanowires. Imogolites (Al2SiO3(OH)4) are natural aluminosilicate single wall nanotubes. To date, only Ge-Al Imogolite analogues have been successfully synthesized 100 times more concentrated than Si-Al Imogolites. The growth mechanisms of Imogolite-like aluminogermanate nanotubes were examined using a combination of local- (XAS at the Ge-Kedge and 27Al NMR) and semilocal scale techniques (in situ SAXS). A model is proposed for the precursors of the nanotubular structure and consist in rooftile-shaped particles, up to 5 nm in size, with ca. 26% of Ge vacancies and varying curvatures. These precursors assemble to form short nanotubes/nanorings observed during the aging process. The final products are most likely obtained by an edge-edge assembly of these short nanotube segments. Two structures are revealed by SAXS: at 0.25M of Al the Al-Ge Imogolite are double-walled NTs whereas at 0.5 M single-walled NTs are obtained. First tests to reveal cyto and genotoxicity on various vertebrates cells (human fibroblasts and CHO-K1) are interesting. They show a genotoxicity for concentrations from 8 10-5 g/L and effects decreasing from proto-Imogolite to long tubes. (Texte integral)

  • Mechanisms of formation and reactivity of Imogolite types material
    2020
    Co-Authors: Jérôme Rose, Antoine Thill, Perrine Chaurand, Clément Levard, Armand Masion, Emmanuel Doelsch, Isabelle Basile-doelsch, Jean-yves Bottero
    Abstract:

    Reactivity of nanopar8cles represents a central issue for many laboratories around the world. Among many supported efforts the control of the morphology of nanopar8cles is mo8vated by the fact that morphology strongly influence the proper8es of the final products. Among the vast family of available nanopar8cles, Imogolite is a clay nanotube for which perfect control of the diameter is possible. Imogolites were first observed in volcanic soils[1]. They are natural aluminosilicate nanotubes having the general formula (OH)3Al2O3SiOH with a 2 nm external diameter and up to micrometers in length. The impressive monodispersity in Imogolite nanotube diameter has mo8vated research on their forma8on mechanism. Synthesis protocols to produce Imogolite were quickly developed. Farmer et al. were the first to obtain synthe8c Imogolite using low concentra8ons of AlCl3 and SiO 2 monomers as star8ng materials (millimolar concentra8ons of the reagents) [2]. However, the produc8on of large amount of Imogolite or Imogolite type materials remained challenging for long 8me. We will present our most recent results concerning the possibility to produce Imogolite type materials from highly concentrated stock solu8ons. We will also detail the possibility to form double wall Al- Ge nanotubes and the different stages of their forma8on [3-7]. We will then detail the surface reac8vity of these nanotubes toward metals at he lab scale as well as in natural soil. (Resume d'auteur)

  • Alignment of Ge-Imogolite nanotubes in isomalt with tunable inter-tube distances
    RSC Advances, 2020
    Co-Authors: Clément Levard, Antoine Thill, Armand Masion, Cyprien Mauroy, Vladimir Vidal, Astrid Avellan, Andrea P. C. Campos, Jérôme Rose
    Abstract:

    This study shows the almost perfect alignment of inorganic nanotubes (Ge-Imogolite) within polyol filaments. Alignment was obtained by simply cooling a Ge-Imogolite-polyol mixture under mechanical stress. Additionally, inter-tube distances in the plane normal to the filaments can be tuned by simply varying the weight fraction of Imogolite in the starting solution. The ease of the alignment protocol will stimulate interest for testing new applications which require a good control of the pore density and morphology (periodicity, and high monodispersity of the pore size distribution).

  • Elaboration of Cellulose Nanocrystal/Ge-Imogolite Nanotube Multilayered Thin Films
    Langmuir, 2018
    Co-Authors: Cyprien Mauroy, Jérôme Rose, Clément Levard, Celine Moreau, Vladimir Vidal, Bernard Cathala
    Abstract:

    Multilayered thin films combining two oppositely charged nanoparticles (NPs), i.e., cellulose nanocrystals (CNCs) and Ge-Imogolites, have been successfully obtained by the layer-by-layer method. CNC/Ge-Imogolite (NP/NP) film growth patterns were studied by comparing growth mode of all of the nanoparticles thin films to that of films composed of CNC or Ge-Imogolites combined with polyelectrolytes (PEs), i.e., cationic poly(allylamine hydrochloride) and anionic poly-4-styrene sulfonate (NP/PE films). NP/NP and NP/PE films growth patterns were found to be different. To get a deeper understanding of the growth mode of NP/NP, impact of different parameters, such as Imogolites aspect ratio, adsorption time, ionic strength, and repeated immersion/drying, was evaluated and influence of the drying step is emphasized. The aspect ratio of Imogolites was identified as an important feature for the film’s architecture. The short Ge-Imogolites form denser films because the surface packing was more efficient.