Layered Inorganic−Organic Clay-like Nanocomposites Rearrange To Form Silsesquioxanes on Acid Treatment

Abstract

The formation of talc-like compounds by the condensation of organotrialkoxy silanes with magnesium hydroxide has been recently reported. These represent layered hybrid nanomaterials that have a layer thickness of around 1 nm, have organic moieties covalently linked to the layer surfaces, and are called "organoclays." We show that such compounds are sensitive to acid treatment. When a phenylclay is treated with hydrochloric acid, magnesium leaches out, destroying the layered structure. The extent to which magnesium is leached out is a function of the time of the acid treatment and the concentration of the acid used. Magnesium leaches out rapidly when the concentration of acid used to treat the phenyl-clay is higher, and the extent of structural magnesium that is leached out is also higher for higher acid concentrations. Removal of the magnesium rearranges the structure of the phenyl-clay to form oligomeric phenylsilsesquioxanes. FTIR and NMR suggest that the silsesquioxanes formed by acid treatment of the phenyl-clay comprise a mixture of ladderlike and cagelike structures.

Synthetic Talc and Talc‐Like Structures: Preparation, Features and Applications

“…[155][156][157] The sol-gels ynthesis of talc is performed at room temperature for 24 hb yu sing organotrialkoxysilane (RSi(OR') 3 )a sas ilicon source, where Ri st he organic part and R' corresponds to ethoxyo rm ethoxy groups. [137] For example, linear alkyl, [158][159][160] functionalized linear alkyl [134,153,161] and phenyl [162] have been employed for the synthesis of organotalcs (Table1). This synthesis leads to talc with organic moieties covalently linked to the silicon atoms of the tetrahedral sheets and hangingi nt he interlayer space.…”

Organic-inorganic hybrid electrochromic materials, polysilsesquioxanes containing triarylamine, changing color from colorless to blue

“…1c , no sharp peaks were found in the XRD patterns reveals the essentially amorphous structures of PSSOs. In addition, the XRD patterns are in poor agreement with characteristic patterns of ladderlike PSSOs 26 – 29 and so that we have reasons to believe that we have obtained random network PSSOs. In order to exclude the almost impossible linear structure of PSSOs, 29 Si NMR were used to further prove the net structure of PSSOs.…”

“…Zhang prepared three-dimensional organic/inorganic hybrid materials (γ-Glycidoxypropyl)silsesquioxanes), from the hydrolytic condensation of γ-glycidoxypropyl)trimethoxysilane in the presence of an acid catalyst (HCOOH) 22 . Kumaraswamy has prepared hybrid nanomaterials that have a layer thickness of around 1 nm by the condensation of organotrialkoxy silanes 26 .…”

Directed Self-Assembly in Laponite/CdSe/Polyaniline Nanocomposites

“…We observed significant spectral broadening of the SiO bands in the QD exchanged LbL films indicating strong host-guest interactions. [92][93][94][95] Key host-guest interactions governing nanocomposite stability involve hydrogen bonding between the aniline subunits and hydroxyl and oxide groups on the clay surfaces and edges and ion-dipole interactions with interlamellar cations. Morphology Studies of Self-Assembed Lap/QD-AT Aggregates and Lap/QD-AT/PANI Films.…”