Dielectric behavior of organically modified siloxane melting gels

Gambino, Louis; Jitianu, Andrei; Klein, Lisa C.

doi:10.1016/j.jnoncrysol.2012.01.002

Cited by 8 publications

(11 citation statements)

References 23 publications

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“…Hybrid glasses obtained after consolidation may be a replacement for epoxies in microelectronic packaging . The dielectric constant, as determined using impedance spectrometry, was lowest, around 3.3, in the 50% MTES–50% DMDES composition at frequencies greater than 1 kHz.…”

Section: Introductionmentioning

confidence: 99%

“…For example, dimethyldiethoxysilane (DMDES) after hydrolysis-polycondensation forms polydimethylsiloxane (PDMS). Structural studies using 29 Si NMR 8,9 showed that PDMS contains linear molecular chains. However, when DMDES is mixed with alkoxysilanes with higher functionality, such as methyltriethoxysilane (MTES) 2 or tetraethoxysilane (TEOS), 10 it is possible to form cross-linked siloxanes with variable density, flexibility, and hydrophobicity.…”

Section: Introductionmentioning

confidence: 99%

“…However, when DMDES is mixed with alkoxysilanes with higher functionality, such as methyltriethoxysilane (MTES) 2 or tetraethoxysilane (TEOS), 10 it is possible to form cross-linked siloxanes with variable density, flexibility, and hydrophobicity. 11 Using 29 Si NMR, Monredon-Senani et al 12 found that the silica surface was covalently grafted with methyl groups, when using MTES or DMDES, which increased the hydrophobicity of the silica surface. Bennevault-Celton et al 13 showed that DMDES along with aminoalkylaloxysilane were used to preserve the flexibility of aging cellulosic paper in items of cultural heritage.…”

Section: Introductionmentioning

confidence: 99%

“…Kuniyoshi et al 17 investigated the initial hydrolysis-polycondensation of PhTES in an acid medium using 29 Si NMR and gel permeation chromatography (GPC). They demonstrated that hydrolysis and polycondensation proceeded simultaneously in the presence of hydrochloric acid.…”

Section: Introductionmentioning

confidence: 99%

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Hybrid Sol–Gel Glasses with Glass‐Transition Temperatures Below Room Temperature

2015

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Melting gels are hybrid gels that have the ability to soften and flow at around 100°C for some combinations of mono-and di-substituted alkoxysiloxanes, where substitutions are either all aromatic or all aliphatic. In this study, melting gels were prepared using phenyltriethoxysilane (PhTES) and dimethyldiethoxysilane (DMDES), meaning both an aromatic and aliphatic substitution. Differential scanning calorimetry was performed to identify glass-transition temperatures, and thermal gravimetric analysis coupled with differential thermal analysis (TGA-DTA) was performed to measure weight loss. The glass-transition temperatures (T g ) ranged from -61°C to +5.6°C, which are between the values in the methyl only system, where all T g values are less than 0°C, and those values in the phenyl only system, where T g values are greater than 0°C. The T g decreased with an increase in the DMDES fraction. Below 450°C, the gels lost little weight, but around 600°C there was a drop in weight. This temperature is lower than the temperature for gels prepared with only aromatic substitutions, but higher than that for gels prepared with only aliphatic substitutions. Final heat treatment was carried out at 150°C for the gel with 80%PhTES-20%DMDES (in mol%), and the consolidation temperature increased with increasing DMDES content to 205°C for the gel with 50%PhTES-50%DMDES. After this heat treatment, the melting gels no longer soften.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Hybrid Sol–Gel Glasses with Glass‐Transition Temperatures Below Room Temperature

2015

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“…The hybrid glasses obtained from these melting gels were characterized by FT-IR and Raman spectroscopy 5,12 . These glasses, which are obtained at relatively low temperatures (135–160 °C) 5 , perform well as anticorrosive coatings 12 and as hermetic barriers 13,14 and also have low dielectric constants 15 . While several applications have been pursued for these hybrid glasses, an understanding of their molecular structure is still incomplete.…”

Section: Introductionmentioning

confidence: 99%

²⁹Si NMR and SAXS investigation of the hybrid organic–inorganic glasses obtained by consolidation of the melting gels

et al. 2017

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This study is focused on structural characterization of hybrid glasses obtained by consolidation of melting gels. The melting gels were prepared in molar ratios of methyltriethoxysilane (MTES) and dimethyldiethoxysilane (DMDES) of 75%MTES-25%DMDES and 65%MTES-35%DMDES. Following consolidation, the hybrid glasses were characterized using Raman, 29Si and 13C Nuclear Magnetic Resonance (NMR) spectroscopies, synchrotron Small Angle X-Ray Scattering (SAXS) and scanning electron microscopy (SEM). Raman spectroscopy revealed the presence of Si-C bonds in the hybrid glasses and 8-membered ring structures in the Si-O-Si network. Qualitative NMR spectroscopy identified the main molecular species, while quantitative NMR data showed that the ratio of trimers (T) to dimers (D) varied between 4.6 and 3.8. Two-dimensional 29Si NMR data were used to identify two distinct types of T3 environments. SAXS data showed that the glasses are homogeneous across the nm to micrometer length scales. The scattering cross section was one thousand times lower than what is expected when phase separation occurs. The SEM images show a uniform surface without defects, in agreement with the SAXS results, which further supports that the hybrid glasses are nonporous.

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Sol-Gel Glasses

Klein

2019

Springer Handbook of Glass

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Dielectric behavior of organically modified siloxane melting gels

Cited by 8 publications

References 23 publications

Hybrid Sol–Gel Glasses with Glass‐Transition Temperatures Below Room Temperature

Hybrid Sol–Gel Glasses with Glass‐Transition Temperatures Below Room Temperature

²⁹Si NMR and SAXS investigation of the hybrid organic–inorganic glasses obtained by consolidation of the melting gels

Sol-Gel Glasses

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Dielectric behavior of organically modified siloxane melting gels

Cited by 8 publications

References 23 publications

Hybrid Sol–Gel Glasses with Glass‐Transition Temperatures Below Room Temperature

Hybrid Sol–Gel Glasses with Glass‐Transition Temperatures Below Room Temperature

29Si NMR and SAXS investigation of the hybrid organic–inorganic glasses obtained by consolidation of the melting gels

Sol-Gel Glasses

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Resources

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²⁹Si NMR and SAXS investigation of the hybrid organic–inorganic glasses obtained by consolidation of the melting gels