Organically modified silicates and ceramics as two-phasic systems: Synthesis and processing

Abstract

Abstract. Based on the concept of controlling the particle size by the surface free energy, the growth of sol-gel derived nanoparticles (A1203, Tit2, ZrO2) has been investigated in presence of molecules with binding ability to the growing particles. The investigations show that the use of silanes, carboxylic acid or fl-diketones allows to replace electrostatic sol stabilisation by steric sol stabilisation and through this, high solid content sols can be obtained. The introduction of these sols into organic or ormocer type of matrices leads to nano composites with degrees of filling up to 40 wt.-% without agglomeration and with high optical quality. Already developed Tit2 containing bulk materials, ultrahard coatings on plastic and adhesives for fiber to chip coupling are examples for the usefulness of this alternative sol-gel route. The nanocomposite materials show interesting mechanical and thermomechanical properties such as high hardness or low thermal expansion compared to unfilled systems.

Low optical loss planar waveguides prepared in an organic–inorganic hybrid system

“…In this way, loading silica based hosts with different nanosized materials, one can tailor refractive index, increase scratch resistance, or enhance optical properties. 3,7,8 In particular, the ͑3-glycidoxipropil͒trimethoxisilane (GPTS) -HfO 2 binary system could be of significant technological importance because it offers the possibility of producing planar waveguides with a controlled refractive index depending on the HfO 2 /GPTS molar ratio. Hafnium dioxide is transparent over the range from 300 nm to 10 m and exhibits high refractive index, about 1.95 at 1000 nm.…”

Fabrication of ultrathin films of Ta2O5 by a sol–gel method

“…Firstly, the particles in the sols can be stabilized electrostatically by preparation via an acidbase-catalyzed sol-gel route. Secondly, the sol particles can be stabilized by the use of chelating/complexing agents to avoid fast condensation and rapid particle growth [18]. In this study, the latter method was employed, utilizing diethanolamine (DEA) as sol-stabilizer.…”

Eu3+ doped polyphosphate–aminosilane organic–inorganic hybrids

“…13 C and 29 Si NMR spectra were recorded at 100.62 and 79.49 MHz, respectively, on a (9.4 T) Bruker Avance400 spectrometer. 1 H-13 C cross-polarization (CP) magic-angle spinning (MAS) NMR spectra were collected with a 4 s 1 H 90 • pulse, 1 ms contact time, a spinning rate of 6 kHz and 4 s recycle delays. 29 Si MAS NMR spectra were recorded with 40 • pulses, a spinning rate of 5 kHz and 60 s recycle delays.…”

“…Organic-inorganic hybrids have emerged as potential hosts in different technological fields ranging from electrochemistry, biology, mechanics, ceramics, electronics to photonics [1][2][3][4]. In general, the main interest in these molecular scale composite materials basically derives from the possibility of tailoring the properties of novel multi-functional advanced materials through a combination, at the nanosize level, of organic and inorganic components in a single material.…”