Fundamental understanding of the formation of industrial crystalline substances is key for developing advanced sustainable materials.

Short documentary video of the research project "Controlling M-S-H Crystallization for Building a Green Future" for which Cristina Ruiz-Agudo won the Messmer Research Award 2021.

Even though crystallization processes are ubiquitous and relevant in a wide range of applications, the underlying mechanisms remain mostly unclear. Controlling crystallization by using additives is central for several scientific and industrial processes. In additive-controlled crystallization, obtaining insights into the stages involved in the formation of solid crystalline materials from their basic building units (i.e., atoms, ions, molecules) and identifying the means by which this process can be modified, are essential for engineering advanced sustainable materials.

In the last decades, the classical notion of crystallization, which considers that crystals grow only by attaching atomic or molecular units, has been challenged. Apart from the existence of solute prenucleation species, liquid, and solid amorphous intermediates, nanoparticle-based aggregation mechanisms have been revealed as a common strategy to produce crystalline materials. The identification of these intermediate stages during crystallization allows completely new synthesis strategies for crystals, and a deeper understanding of mineralization processes in general, which can be applied to avoid, enhance, or control their formation. Relevant characteristics of the crystals such as particle size, morphology, or polymorphism could be targeted by aiming specific interactions of the additives with these intermediate stages to the final crystalline material.

Determining the influence of additives on the crystallization of a wide range of relevant industrial materials from solution is the focus of the Ruiz-Agudo group. Applying various state-of-the-art techniques, such potentiometric titration, atomic force microscopy, and analytical ultracentrifugation, the design of specific additives architectures can be optimized towards the desired interactions with different crystalline materials.