Spectroscopic characterization of sol–gel organo-siloxane materials synthesized from aliphatic and aromatic alcoxysilanes

Oubaha, Mohamed; Etienne, Pascal; Calas, S.; Sempéré, R.; Nédélec, Jean-Marie; Moreau, Yves

doi:10.1016/j.jnoncrysol.2005.03.049

Cited by 27 publications

(26 citation statements)

References 16 publications

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“…3). The final spectrum shows the disappearance of the initial T 0 0 group observed in the precursor coupled with the appearance of 3 bands located around −50, −59, −69 ppm in the typical T 1 , T 2 and T 3 regions respectively [32]. These bands are actually composed of several peaks indicating different degrees of hydrolysis for the silicon atom in each configuration, as summarised in Table 1.…”

Section: Si Nmr Spectroscopymentioning

confidence: 91%

“…Solution A was slowly added to solution B over 10 min and was characterised by an exothermic reaction indicating the hydrolysis of the remaining propoxy bonds on the zirconium precursor, rather than a physical dispersion, was occurring. Following a further 45 min, water (pH 7) was added to the mixture to give a final molar ratio of 2.5:1:1:5 (MAPTMS: Ligand: TPOZ: H 2 O), as used previously [31,32]. For comparative purposes a MAPTMS sol-gel was prepared by combining the silane precursor, dilute HNO 3 (aq) as catalyst, ethanol as solvent and water for hydrolysis with a molar ratio of 1/0.001/2.5/5 (MAPTMS/HNO 3 /ETOH/ H 2 O).…”

Section: Sol-gel Synthesismentioning

confidence: 99%

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Corrosion protection of AA 2024-T3 aluminium alloys using 3, 4-diaminobenzoic acid chelated zirconium–silane hybrid sol–gels

Varma

Colreavy

Cassidy³

et al. 2010

Thin Solid Films

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Organic-inorganic polymers formed by hydrolysis/condensation reactions of alkoxide precursors, such as organically modified silanes (Ormosils) are used for several industrial applications such as electronic, optical and protective anticorrosion coatings. Such materials possess superior chemical stability, physical strength and scratch resistance characteristics when compared to organic polymers. Further performance improvement can be achieved through the incorporation of zirconium and titanium based nanoparticles, also formed through from precursors via the sol-gel process. However due to the inherent reactivity differences of the above precursors, they must be hydrolysed separately before being combined for final condensation. Zirconium precursors are commonly chelated using acetic acid or acetyl acetonate prior to hydrolysis, to lower the hydrolysis rate. In this body of work, 3,4-diaminobenzoic acid (DABA) and acetyl acetonate (acac) were compared as chelating ligands for controlling the hydrolysis reactions of zirconium n-propoxide to form nanoparticles within a silane sol matrix. The sols were applied as coatings on aerospace grade aluminium alloy AA 2024-T3 and characterised by physical, spectroscopical, microscopical, electrochemical and calorimetric techniques. The electrochemical properties of the coatings, as characterised by EIS and PDS, correlated with neutral salt spray evaluations confirming that the use of DABA as a chelating ligand significantly improved the coating performance when compared to the traditional diketone ligand. The data indicates the anticorrosion properties of the nitrogen rich chelate have a key role in protecting the alloy through the formation of smaller zirconium nanoparticles, thus improving the polymer network stability.

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Section: Si Nmr Spectroscopymentioning

confidence: 91%

Section: Sol-gel Synthesismentioning

confidence: 99%

Corrosion protection of AA 2024-T3 aluminium alloys using 3, 4-diaminobenzoic acid chelated zirconium–silane hybrid sol–gels

Varma

Colreavy

Cassidy³

et al. 2010

Thin Solid Films

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“…In a similar structure, the progressive condensation provoked an increase of 10 ppm [19,20]. Based on the literature, it is possible to confirm that the peaks observed in the sample recorded after 1 hour of reaction are not attributable to any condensed silica species.…”

Section: 1mentioning

confidence: 56%

Structural and Optical Characterisation of an Erbium/Ytterbium Doped Hybrid Material Developed via a Nonhydrolytic Sol-Gel Route

Oubaha

Copperwhite

McDonagh

et al. 2010

SRX Materials Science

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This paper proposes the development and structural characterisation of an Er 3+ /Yb 3+ doped hybrid organic-inorganic material synthesised by a nonhydrolytic sol-gel process. By using a pumping laser diode at 980 nm, a typical Er 3+ luminescence has been recorded in the near infrared region (1.53-1.55 μm). However, the detected fluorescence was particularly weak compared to that generally observed in pure mineral materials, suggesting the occurrence of strong quenching due to multiphonon relaxation processes. To understand this behaviour, structural characterisation of both of the matrix and the local environment of Er 3+ ions were conducted employing infrared spectroscopy, nuclear magnetic resonance, electron paramagnetic resonance, and neutron scattering. These studies showed that the major phenomenon competing with the Er 3+ fluorescence is intimately associated to the strong vibrational modes of the organic species that involve multiphonon relaxation processes, resulting in energy dissipation within the host matrix.

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“…The absorption vibrations involving the Zr-OPr group are primarily located in the range 800-1300 cm −1 [34] and do not show any absorption beyond 1500 cm −1 . Within the 1300-1800 cm −1 spectral range, the chelated TPOZ shows several absorption bands inherent to the fundamental vibration of the zirconium nanoparticle [31]. The Zr/ligand complexes synthesised with carboxylic acids ligands (MAAH, IBA, and AcOH) have two peaks in the 1500-1700 cm −1 region, which are clearly ascribable to the symmetric ( s ) and asymmetric stretching ( as ) vibrations of the carboxylic group (COO − ) respectively [35].…”

Section: Ftir Resultsmentioning

confidence: 99%

“…Solution A was slowly added to solution B over 10 min. The mixture of A with B is characterised by an exothermic reaction indicating the hydrolysis of the remaining propoxy bonds on the zirconium precursor, rather than a physical dis- [31]. For description purposes the final sol-gel coating materials will be referred in shorthand notation as Si/Zr/ligand (e.g.…”

Section: Synthesis Of Hybrid Solsmentioning

confidence: 99%

Effect of organic chelates on the performance of hybrid sol–gel coated AA 2024-T3 aluminium alloys

Varma

Colreavy

Cassidy³

et al. 2009

Progress in Organic Coatings

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a b s t r a c tSol-gels are organic-inorganic polymers formed by hydrolysis/condensation reactions of alkoxide precursors, primarily silanes, which have found applications as electronic, optical and protective coatings. These coatings possess important characteristics such as chemical stability, physical strength and scratch resistance. Further performance improvement is achieved through the incorporation of zirconium and titanium based nanoparticles, also formed through the sol-gel process. However due to the inherent difference in the reactivity of the precursors, the hydrolysis of each precursor must be carried out separately before being combined for final condensation. Zirconium precursors are commonly chelated using acetic acids, prior to hydrolysis, to lower the hydrolysis rate.In this body of work various ligands such as organic acids, acetyl acetone (AcAc) and 2,2 -bipyridine (Bipy) were used to control the zirconium hydrolysis reaction and form nanoparticles within the silane sol matrix.Nanoparticle modified coatings formed from the silane sol on AA 2024-T3 aluminium were characterised spectroscopically, electrochemically and calorimetrically to evaluate the potential effect of the different chelates on the final film properties while neutral salt spray tests were performed to study their anti-corrosion performance. Results indicate that the acid ligand modified coatings provided the best performance followed by AcAc, while Bipy was the poorest. In all cases the zirconium nanoparticle improved the protective properties of the sol-gel coating.

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Spectroscopic characterization of sol–gel organo-siloxane materials synthesized from aliphatic and aromatic alcoxysilanes

Cited by 27 publications

References 16 publications

Corrosion protection of AA 2024-T3 aluminium alloys using 3, 4-diaminobenzoic acid chelated zirconium–silane hybrid sol–gels

Corrosion protection of AA 2024-T3 aluminium alloys using 3, 4-diaminobenzoic acid chelated zirconium–silane hybrid sol–gels

Structural and Optical Characterisation of an Erbium/Ytterbium Doped Hybrid Material Developed via a Nonhydrolytic Sol-Gel Route

Effect of organic chelates on the performance of hybrid sol–gel coated AA 2024-T3 aluminium alloys

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