Hydrogen bonding between adsorbed gases and surface hydroxyl groups on silica

1968 ◽  
Vol 72 (13) ◽  
pp. 4676-4682 ◽  
Author(s):  
William Hertl ◽  
Michael L. Hair
Keyword(s):  
Hydrogen Bonding ◽  
Hydroxyl Groups ◽  
Surface Hydroxyl ◽  
Surface Hydroxyl Groups

Kaolinite hydroxyls – a Raman microscopy study

Clay Minerals ◽  
1997 ◽  
Vol 32 (3) ◽  
pp. 471-484 ◽  
Author(s):  
R. L. Frost ◽  
S. J. van der Gaast
Keyword(s):  
Hydrogen Bonding ◽  
Domain Size ◽  
Microscopy Study ◽  
Raman Microscopy ◽  
Hydroxyl Groups ◽  
Surface Hydroxyl ◽  
Surface Hydroxyl Groups ◽  
Inner Surface ◽  
Relationship Of ◽  
Spectral Intensities

AbstractRaman microscopy of the kaolinite polymorphs was used to study single crystals and bundles of aligned crystals of kaolinite. The spectra of the hydroxyl stretching region were both sample and orientation dependent. Kaolinites can be classified into two groups according to the ratio of the intensities of the 3685 and 3695 cm−1 bands. No relationship was found between the d-spacing and the crystal domain size measurement from the 001 reflection and the Raman spectral intensities indicating the Raman spectra are independent of d-spacing and crystallinity. However, a relationship of the crystallinity in the a-b direction and intensities of the 3685 and 3695 cm−1 bands indicate that the relative position of one layer to the other determines the position of the inner surface hydroxyl groups and the hydrogen bonding with the oxygen of the opposite layer. A new hypothesis based on symmetric and non-symmetric hydrogen bonding of the inner surface hydroxyl groups is proposed to explain the two inner surface hydroxyl bands centred at 3685 and 3695 cm−1. The bands at 3670 and 3650 cm−1 are described in terms of the out-of-phase vibrations of the in-phase vibrations at 3695 and 3685 cm−1.

scholarly journals Novel Hybrid Materials And Their Applications

2021 ◽  
Author(s):  
◽  
Aaron Charles Small
Keyword(s):  
Quantum Dots ◽  
Hydrogen Bonding ◽  
Magnetite Nanoparticles ◽  
Uv Light ◽  
Precipitation Method ◽  
Hydroxyl Groups ◽  
Cellulose Fibres ◽  
X Ray ◽  
Surface Hydroxyl ◽  
Surface Hydroxyl Groups

<p>The development of novel hybrid materials of cellulose fibres and substrates with nanoparticles, conducting polymers and quantum dots, opens up novel application for new packaging materials and paper based products for the ‘smart packaging’ and ‘functional products’ areas that are emerging in the paper and packaging industries. Examples of these materials which have been developed here include cellulose fibres and substrates functionalised with magnetic nanoparticles, electrically conducting polypyrrole, and photoluminescent zinc sulfide quantum dots.  Such materials were synthesised and then characterised using Alternating Gradient Magnetometry (AGM), Atomic Absorption Spectroscopy (AA), Cotec Profilometer Measurements, DC Conductivity Measurements, Photoluminescence Spectroscopy (PL), Scanning Electron Microscopy (SEM), SQUID Magnetometry, Transmission Electron Microscopy (TEM), Vibrational Sample Magnetometry (VSM), X-ray Diffraction (XRD), X-ray Fluorescence (XRF) and X-ray Photoelectron Spectroscopy (XPS).  Ferrimagnetic magnetite nanoparticles (particle size 12-26 nm) were synthesised by a simple aqueous precipitation method and had a magnetic saturation of approximately 60 emu g⁻¹, a coercive field of approximately 12-120 Oe, and a remnant magnetisation of approximately 11 emu g⁻¹.  Magnetite coated Kraft fibres (1.2 – 3.15 wt. % Fe) were synthesised by adding a colloidal suspension of magnetite nanoparticles to a suspension of Kraft fibres. The fibres retained their inherent properties, such as tensile strength and flexibility, but inherited the magnetic properties of the magnetic nanoparticles. The nanoparticles remained unchanged on bonding - presumably through hydrogen bonding between the surface hydroxyl groups of the cellulose and the oxygen present in the magnetite.  Newsprint, Kraft Board and Cotton fabric were coated with polypyrrole using a chemical polymerisation method. SEM shows a complete coating, whereby the fibres are completely encapsulated by the polymer, including individual fibrils. Again, bonding is facilitated through hydrogen bonding between the surface hydroxyl groups of the cellulose and the lone pairs of the nitrogen in the polypyrrole backbone. Samples were doped with p-toluenesulfonic acid to increase conductivity, of which up to 4 S cm⁻¹ was achieved.  The samples were coated with magnetite nanoparticles using a starch binder, and tested for their application in EMI shielding. A maximum shielding effectiveness of 43 % in the 1-18 GHz range and 47 % in the 16-40 GHz range was obtained using cotton fabrics coated with both polypyrrole and magnetite. A synergistic effect is observed on using a polypyrrole and magnetite coating.  Photoluminescent ZnS quantum dots, synthesised using an aqueous precipitation method, were doped with Mn²⁺ and Cu²⁺ to achieve emissions at approximately 600 nm (Mn²⁺) and 530 nm (Cu²⁺) on irradiation with UV light. The quantum dots had a particle size of approximately 2 nm, and were present in the zinc blende phase.  Doped ZnS-coated Kraft fibres (5 – 30 wt. % Zn) were synthesised by a number of methods, the most successful being the ‘in-situ’ method, in which a uniform and complete coating was afforded. The fibres retained their inherent properties, such as tensile strength and flexibility, but inherited the photoluminescent properties of the ZnS quantum dots. The quantum dots remained unchanged on bonding - presumably through hydrogen bonding between the surface hydroxyl groups of the cellulose and the sulfur present in the ZnS quantum dots.  ZnS quantum dots doped with Mn² and Cu²⁺ were successfully formulated for inkjet printing by capping with mercaptosuccinic acid. Upon irradiation with UV light, emissions at approximately 600 nm (Mn²⁺-doped) and 530 nm (Cu²⁺-doped) were observed. These were successfully inkjet printed in intricate patterns onto a number of substrates, including photographic quality inkjet paper, cotton, and wool.</p>

scholarly journals Novel Hybrid Materials And Their Applications

2021 ◽  
Author(s):  
◽  
Aaron Charles Small
Keyword(s):  
Quantum Dots ◽  
Hydrogen Bonding ◽  
Magnetite Nanoparticles ◽  
Uv Light ◽  
Precipitation Method ◽  
Hydroxyl Groups ◽  
Cellulose Fibres ◽  
X Ray ◽  
Surface Hydroxyl ◽  
Surface Hydroxyl Groups

<p>The development of novel hybrid materials of cellulose fibres and substrates with nanoparticles, conducting polymers and quantum dots, opens up novel application for new packaging materials and paper based products for the ‘smart packaging’ and ‘functional products’ areas that are emerging in the paper and packaging industries. Examples of these materials which have been developed here include cellulose fibres and substrates functionalised with magnetic nanoparticles, electrically conducting polypyrrole, and photoluminescent zinc sulfide quantum dots.  Such materials were synthesised and then characterised using Alternating Gradient Magnetometry (AGM), Atomic Absorption Spectroscopy (AA), Cotec Profilometer Measurements, DC Conductivity Measurements, Photoluminescence Spectroscopy (PL), Scanning Electron Microscopy (SEM), SQUID Magnetometry, Transmission Electron Microscopy (TEM), Vibrational Sample Magnetometry (VSM), X-ray Diffraction (XRD), X-ray Fluorescence (XRF) and X-ray Photoelectron Spectroscopy (XPS).  Ferrimagnetic magnetite nanoparticles (particle size 12-26 nm) were synthesised by a simple aqueous precipitation method and had a magnetic saturation of approximately 60 emu g⁻¹, a coercive field of approximately 12-120 Oe, and a remnant magnetisation of approximately 11 emu g⁻¹.  Magnetite coated Kraft fibres (1.2 – 3.15 wt. % Fe) were synthesised by adding a colloidal suspension of magnetite nanoparticles to a suspension of Kraft fibres. The fibres retained their inherent properties, such as tensile strength and flexibility, but inherited the magnetic properties of the magnetic nanoparticles. The nanoparticles remained unchanged on bonding - presumably through hydrogen bonding between the surface hydroxyl groups of the cellulose and the oxygen present in the magnetite.  Newsprint, Kraft Board and Cotton fabric were coated with polypyrrole using a chemical polymerisation method. SEM shows a complete coating, whereby the fibres are completely encapsulated by the polymer, including individual fibrils. Again, bonding is facilitated through hydrogen bonding between the surface hydroxyl groups of the cellulose and the lone pairs of the nitrogen in the polypyrrole backbone. Samples were doped with p-toluenesulfonic acid to increase conductivity, of which up to 4 S cm⁻¹ was achieved.  The samples were coated with magnetite nanoparticles using a starch binder, and tested for their application in EMI shielding. A maximum shielding effectiveness of 43 % in the 1-18 GHz range and 47 % in the 16-40 GHz range was obtained using cotton fabrics coated with both polypyrrole and magnetite. A synergistic effect is observed on using a polypyrrole and magnetite coating.  Photoluminescent ZnS quantum dots, synthesised using an aqueous precipitation method, were doped with Mn²⁺ and Cu²⁺ to achieve emissions at approximately 600 nm (Mn²⁺) and 530 nm (Cu²⁺) on irradiation with UV light. The quantum dots had a particle size of approximately 2 nm, and were present in the zinc blende phase.  Doped ZnS-coated Kraft fibres (5 – 30 wt. % Zn) were synthesised by a number of methods, the most successful being the ‘in-situ’ method, in which a uniform and complete coating was afforded. The fibres retained their inherent properties, such as tensile strength and flexibility, but inherited the photoluminescent properties of the ZnS quantum dots. The quantum dots remained unchanged on bonding - presumably through hydrogen bonding between the surface hydroxyl groups of the cellulose and the sulfur present in the ZnS quantum dots.  ZnS quantum dots doped with Mn² and Cu²⁺ were successfully formulated for inkjet printing by capping with mercaptosuccinic acid. Upon irradiation with UV light, emissions at approximately 600 nm (Mn²⁺-doped) and 530 nm (Cu²⁺-doped) were observed. These were successfully inkjet printed in intricate patterns onto a number of substrates, including photographic quality inkjet paper, cotton, and wool.</p>

The synthesis and structure of silica-supported bis(h5-cyclopentadienyl)dichlorotitanium(IV) complexes

1986 ◽  
Vol 51 (7) ◽  
pp. 1430-1438 ◽  
Author(s):  
Alena Reissová ◽  
Zdeněk Bastl ◽  
Martin Čapka
Keyword(s):  
Free Surface ◽  
Hydroxyl Groups ◽  
Titanium Complex ◽  
Surface Hydroxyl ◽  
Surface Hydroxyl Groups ◽  
Free Hydroxyl ◽  
Cyclopentadienyl Anion

The title complexes have been obtained by functionalization of silica with cyclopentadienylsilanes of the type Rx(CH3)3 - xSi(CH2)nC5H5 (x = 1-3, n = 0, 1, 3), trimethylsilylation of free surface hydroxyl groups, transformation of the bonded cyclopentadienyl group to the cyclopentadienyl anion, followed by coordination of (h5-cyclopentadienyl)trichlorotitanium. The effects of single steps of the above immobilization on texture of the support, the number of free hydroxyl groups, the coverage of the surface by cyclopentadienyl groups and the degree of their utilization in anchoring the titanium complex have been investigated. ESCA study has shown that the above anchoring leads to formation of the silica-supported bis(h5-cyclopentadienyl)dichlorotitanium(IV) complex.

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