Understanding the formation mechanisms of solids poses various fundamental challenges en route to the rational design of multifunctional materials with targeted properties. Solid formation encompasses a range of chemico-physical phenomena - mixing, reaction, nucleation, growth, and aggregation - that are intricately interwoven. These transformations span a broad spectrum of sizes, from the molecular to the micron level, and time scales from seconds to hours. One possible strategy to cope with this complexity is the implementation of multiple and simultaneous in situ analytical and spectroscopic techniques to monitor the evolution of the reaction mixtures in real time.[1]

General guiding principles for the effective design and analysis of the experimental data will be highlighted for nanoparticles, mesocrystals, and non-classical crystallization [2] as specific examples. Non-classical crystallization will be explored, including the formation of ZnO/PVP mesocrystals monitored using in situ DLS and turbidity measurements, [3] the transition from amorphous to crystalline solids monitored via in situ ATR-FTIR spectroscopy, [4] and the formation of goethite particles tracked with in situ Raman spectroscopy, pH, and dissolved oxygen concentration. [5,6]

This presentation will also delve into the development of general guidelines aimed at predicting whether a material will undergo classical or non-classical growth processes. These guidelines will be based on a comprehensive analysis of various factors, including the chemical composition of the materials, the environmental conditions during synthesis (such as temperature, pH, and solvent type), and the dynamic interplay between different phases during the formation process. By integrating these factors, a predictive framework can assist material scientists and engineers in anticipating the growth behavior of new materials, thereby streamlining the design and synthesis of advanced materials with desired properties and functionalities. This predictive capability is not only fundamental for the advancement of material science but also holds significant implications for a wide range of industries, from pharmaceuticals to electronics, where the control over material structure at the nanoscale can lead to groundbreaking applications.

References
[1] Embrechts, M. Hartmann, W. Peukert, M. Distaso Chem. Eng. Tech. 2020, 43, 879-886.
[2] H. Coelfen, M. Antonietti Ang. Chem. Int. Ed. 2005, 44, 5576-5591.
[3] H. Embrechts, S. Zhang, R. Hock, W. Peukert, M. Distaso Cryst. Growth Des. 2020, 20, 1266-1275.
[4] A. Güldenpfennig, M. Distaso, W. Peukert Chem. Eng. J. 2019, 369, 996-1004.
[5] E. R. Encina, M. Distaso, R. N. Klupp Taylor, W. Peukert Cryst. Growth Des. 2015, 15, 194-203.
[6] M. Michaud, W. Peukert, M. Distaso Powder Technology 2023, 427, 118677.