29Si MAS NMR and FTIR study of inorganic–organic hybrid gels

Olejniczak, Zbigniew; Łęczka, M.; Cholewa‐Kowalska, Katarzyna; Wojtach, K.; Rokita, M.; Mozgawa, W.

doi:10.1016/j.molstruc.2004.11.069

Cited by 115 publications

(77 citation statements)

References 14 publications

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“…[13] Further drawbacks include crack formation in coatings, brittleness of sols or high sintering temperatures necessary for complete densification. These limitations were overcome by adding organic modifiers [14] to the inorganic network to promote the elasticity of the gel. It was shown that only 5% of star alkoxysilane molecules into the inorganic network during sol/gel synthesis substantially increased the toughness, with a Young's modulus within a factor of 2 of that of the inorganic glass.…”

Section: Introductionmentioning

confidence: 99%

Low‐Stress Hyperbranched Polymer/Silica Nanostructures Produced by UV Curing, Sol/Gel Processing and Nanoimprint Lithography

Geiser

Leterrier

2011

Macro Materials & Eng

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Nanocomposite materials based on a HBP and silica are produced using either a dual‐cure sol/gel and photopolymerization process or by mixing silica nanoparticles with the HBP. In both cases the conversion of the HBP is independent of composition and obeys a time‐intensity superposition with power‐law dependence on UV intensity. Optimization of the dual‐cure process leads to transparent sol/gel composites with ultrafine structures. These materials systematically outperform the particulate composites, including an increase of the glass transition temperature of 63 °C and a process‐induced internal stress as low as 2.5 MPa. Nano‐sized gratings are produced from the sol/gel composites by low‐pressure UV nanoimprint lithography.magnified image

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Section: Introductionmentioning

confidence: 99%

Low‐Stress Hyperbranched Polymer/Silica Nanostructures Produced by UV Curing, Sol/Gel Processing and Nanoimprint Lithography

Geiser

Leterrier

2011

Macro Materials & Eng

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“…Subtraction of the spectrum of PPSU from that of SiPPSU is shown in Figure 1d to highlight the signals characteristic of silicon-phenyl bonds. Numerous studies directed towards the identification of frequencies apt to characterise the silicon-phenyl bond have been reported [27][28][29]. Most authors concentrated their attention on bands at 1,430 and 1,100 cm -1 .…”

Section: Original Research Papermentioning

confidence: 99%

Proton Conducting Hybrid Membranes Based on Aromatic Polymers Blends for Direct Methanol Fuel Cell Applications

Bonis¹,

D’Epifanio²,

Vona³

et al. 2009

Fuel Cells

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Composite membranes made‐up of sulphonated polyetheretherketone (SPEEK, DS = 0.5) and of a sulphonated and silylated hybrid organic–inorganic derivative of polyphenylsulphone (SiSPPSU, DS = 2) were prepared and characterised. The water and methanol uptake, as well as thermal properties, of blend membranes containing 5 and 10 wt.‐% SiSPPSU were evaluated. The electrochemical performance of the membranes was evaluated by electrochemical impedance spectroscopy (EIS) and tested in a direct methanol fuel cell (DMFC) station. The presence of SiSPPSU modified the properties of SPEEK, allowing to increase its performance in terms of proton conductivity, thermal and hydrolytic stability. These blends appeared to be suitable electrolytes for DMFC applications.

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“…7a. The as-prepared sample prior to any redox cycling displayed the characteristic absorption bands of silica which were assigned to siloxane bonds (Si-O-Si) at ~800 and ~1080 cm -1 , and a shoulder at ~950 cm -1 to silanol bonds (Si-O-H) [35][36][37]. It is also observed bands at 660 and 565 cm -1 .…”

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confidence: 98%