Mechanism and Nanosize Products of the Sol−Gel Reaction Using Diphenylsilanediol and 3-Methacryloxypropyltrimethoxysilane as Precursors

Department of Materials Science and Engineering, KAIST, Daejon 305-701, Republic of Korea.
The Journal of Physical Chemistry B (Impact Factor: 3.3). 06/2005; 109(19):9397-403. DOI: 10.1021/jp044151q
Source: PubMed


We use a first-principles calculation and small-angle neutron scattering (SANS) to investigate the mechanism and the nanosize products of the sol-gel reaction with diphenylsilanediol (DPD) and 3-methacryloxypropyltrimethoxysilane (MEMO) precursors in synthesizing a hybrid waveguide material. It is predicted that switching between a DPD hydroxyl and a MEMO methoxy with a reaction rate of 6.8 x 10(-6) s(-1) at 300 K is the fastest process for the first reaction step, thus generating diphenylmethoxysilanol (DPM) and 3-methacryloxypropyldimethoxysilanol (MEDO) as products. However, we determine that this reaction pathway could be modified by the presence of the H2O released from a catalyst such as Ba(OH)2.H2O. Next, switching between the DPM hydroxyl and the MEDO methoxy is followed to generate diphenyldimethoxysilane (DPDM) and 3-methacryloxypropylmethoxysilanediol (MEMDO). However, condensation between a MEMDO hydroxyl and a DPDM methoxy is found to be most favorable for the third reaction step, which generates the DPDM-MEMDO dimer and CH3OH molecule as products. In a similar fashion, a DPDM methoxy of the DPDM-MEMDO dimer can condense with a MEMDO hydroxyl of the second DPDM-MEMDO dimer to increase the chain, but its reaction rate of 2.8 x 10(-11) s(-1) is predicted to be about 5 times smaller than that between a DPDM methoxy and a MEMDO hydroxyl. This implies that the reaction rate for the larger nanostructures becomes smaller. Additionally, our SANS measurements determine that the final products from our sol-gel reaction are on the nanometer scale, at sizes from 1.76 to 2.36 nm.

Download full-text


Available from: Saji Augustine, Oct 04, 2015
1 Follower
48 Reads
  • [Show abstract] [Hide abstract]
    ABSTRACT: A new method for the fabrication of microstructured polymer surfaces possessing features with different 3D geometries is reported. Controlled micromolding using masters with 2D topographies and fluid elastomeric precursors with various viscosities and crosslinking kinetics yielded homogeneously structured surfaces possessing microtubes and concave and convex hemispheres with defined dimensions. This fabrication strategy does not require sophisticated 3D structuring equipment and can be extended to other materials, dimensions and geometries.
    Advanced Functional Materials 10/2007; 17(17):3590 - 3597. DOI:10.1002/adfm.200700132 · 11.81 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The interest in organic-inorganic hybrids as materials for optics and photonics started more than 25 years ago and since then has known a continuous and strong growth. The high versatility of sol-gel processing offers a wide range of possibilities to design tailor-made materials in terms of structure, texture, functionality, properties and shape modelling. From the first hybrid material with optical functional properties that has been obtained by incorporation of an organic dye in a silica matrix, the research in the field has quickly evolved towards more sophisticated systems, such as multifunctional and/or multicomponent materials, nanoscale and self-assembled hybrids and devices for integrated optics. In the present critical review, we have focused our attention on three main research areas: passive and active optical hybrid sol-gel materials, and integrated optics. This is far from exhaustive but enough to give an overview of the huge potential of these materials in photonics and optics (254 references).
    Chemical Society Reviews 02/2011; 40(2):886-906. DOI:10.1039/c0cs00106f · 33.38 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: A high thermal-stable methacrylate-silicate hybrid nanocomposite (hybrimer) was fabricated based on UV-induced polymerization of a highly-condensed methacryl-oligosiloxane resin (Hy-MO). The Hy-MO resin was newly synthesized via an acid-catalyzed hydrolytic sol–gel reaction of 3-(methacryloxy) propyl trimethoxysilane (MPTS) and diphenyldimethoxysilane. The basic properties of Hy-MO were compared with a conventional resin prepared by a Ba(OH)2·H2O-catalyzed non-hydrolytic sol–gel reaction of MPTS and diphenylsilanediol (N-MO). It was found that Hy-MO have a higher siloxane condensation degree, larger molecular size and weight than the N-MO due to the highly mobile proton ions that effectively catalyze the overall sol–gel reaction. The resultant Hy-MO hybrimer showed a higher thermal stability than N-MO hybrimer.
    Journal of Sol-Gel Science and Technology 11/2011; 61(2). DOI:10.1007/s10971-011-2630-5 · 1.53 Impact Factor
Show more