Sol–Gel Synthesis of Solids

Abstract

The synthesis of glasses and ceramics via the sol–gel route is based on the inorganic polymerization of molecular precursors such as metal alkoxides. Precursor structure and reactivity can be chemically controlled via complexation or acid–base catalysis. Sol–gel chemistry allows the powderless processing of glasses and ceramics, at much lower temperatures than that at usual solid‐state reactions. It provides a convenient and flexible access to nanoparticles, films, and fibers. Moreover, precursors are mixed at the molecular level and multicomponent materials can be formed. Thus, hybrid organic–inorganic materials have been made via the sol–gel route. The organic component can be used as a network modifier during the sol–gel synthesis and then withdrawn, allowing the formation of structured porous materials. It can also remain entrapped in the mineral matrix via weak interactions. Alternatively, organoalkoxysilanes allow covalent binding of organic moieties to silica networks. Such composites fill the gap between polymers and glasses, opening new possibilities for the design of functional materials in the fast developing areas of energy, biotechnology, and medicine.

Thickness and thermal processing contribution on piezoelectric characteristics of Pb(Zr-Ti)O3 thick films deposited on curved IN738 using sol–gel technique

“…When the prepared PZT solution was coated onto the surface, the evaporation of solvent led to gelation of the metalorganic chains into a rigid structure. 8,16 Having dried at 200℃ on the hot plate for 5 min, the contraction and densification occurred in the specimens as the excess solvent was eliminated. Next, the samples pyrolyzed for 5 min which involved firing to approximately 400℃ in order to burn off the organic compounds.…”