From Chemical Solutions to Inorganic Nanostructured Materials: A Journey into Evaporation-Driven Processes

We present the conventional and emerging methods of preparation of nanostructured materials from chemical solution evaporation where precursors, reactants, and potential structuring agents are homogeneously dispersed or dissolved in a volatile solvent. The liquid is shaped as dictated by the selected process and undergoes evaporation that concentrates the nonvolatile species triggering various chemical phenomena such as reaction, self-assembly, phase separation, nucleation growth, aggregation, etc. While the composition of the final material depends on the initial solution stoichiometry, the morphology is governed by the process and the internal structure is adjusted by the kinetic and thermodynamic aspects of the coupled process. Because many processes involving the later approach exist, we decided to describe some of the more important processes, in terms of applicability and some of the more emerging processes, in terms of added value. More precisely, thin films, two-dimensional (2D) nano-in-micro patterns, hierarchical structures, and powders presented here were prepared by combining the solution evaporation with dip coating, microfabrication and nanofabrication, infiltration replication (especially of butterfly wings), and, finally, spray drying, respectively. The efficiency, throughput, compatibility, and limitation of each process and method are discussed, together with related priority developments to be made in the future.