Structuring of Amide Cross ‐Linked Non‐Bridged and Bridged Alkyl‐Based Silsesquioxanes

Abstract
The development of sophisticated organized materials exhibiting enhanced properties is a challenging topic of the domain of organic/inorganic hybrid materials. This review, composed of four sections, reports the work we have carried out over the last 10 years on the synthesis of amide cross‐linked alkyl/siloxane hybrids by means of sol‐gel chemistry and self‐directed assembly/self‐organization routes relying on weak interactions (hydrophobic interactions and hydrogen bonding). The various as‐produced lamellar structures displaying a myriad of morphologies, often closely resembling those found in natural materials, are discussed. The major role played by the synthetic conditions (pH, water content, co‐solvent(s) nature/concentration and dopant presence/concentration), the alkyl chains (length and presence of ramification or not) and the number of the amide cross‐links present in the precursor, is evidenced. Examples of highly organized hybrids structures incorporating ionic species (alkali and alkaline earth metal salts) and optically‐active centers (organic dyes and lanthanide ions) are described. A useful qualitative relationship deduced between the emission quantum yield of the ordered hybrid materials and the degree of order of the hydrogen‐bonded network is highlighted.

Source: Contrast Media and Molecular Imaging - February 6, 2018 Category: Radiology Authors: S. C. Nunes, V. de  Zea Bermudez Tags: Personal Account Source Type: research