Review: hydrothermal technology for smart materials

In broad terms, hydrothermal synthesis is a technology for crystallising materials (chemical compounds) directly from aqueous solution by adept control of thermodynamic variables (temperature, pressure and composition). The objective of this review is to introduce the field of hydrothermal materials synthesis and show how understanding solution thermodynamics of the aqueous medium can be used for engineering hydrothermal crystallisation processes. In this review, powder synthesis, and their applications are introduced. In Section 'Introduction', we will focus on the hydrothermal synthesis as a materials synthesis technology by providing history, process definitions, technological merits and comments on its current implementation in the laboratory. In Section 'Scope of hydrothermal synthesis in future', we will describe the development of hydrothermal technology for materials synthesis, their results and comparison with other methods.