A Different View of Solvent Effects in Crystallization

Abstract

Solvents are widely used in crystallization, but their effects on the shape development of crystals are under debate. Here, we report a view on how solvents play their role by considering the viscosity of solvents. We synthesize silver particles in a mixture of alcohol and water. The viscosity of the solvent is changed by varying the volume ratio of alcohol in water. With the variation of viscosity, diverse morphologies of silver particles are synthesized. Small cubic crystals are formed at low viscosity, while hierarchical flower-like particles are formed at high viscosity. Two alcohols are employed, namely ethanol and propanol. No matter which alcohol is employed, the results are similar. Due to the limitation of mass transfer at high viscosity, the particles synthesized in such solvent are smaller and stabilized by the solvent. When the solution containing these particles are dropped onto metal substrates, these tiny particles firstly aggregate, which is followed by classic crystallization, forming flower-like hierarchical structures. These findings show the importance of the viscosity of solvents in shaping particles, which is underestimated previously.

Barium sulfate crystallization in non-aqueous solvent

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Additive-Assisted Perylene Polymorphism Controlled via Secondary Bonding Interactions

“…Organic optoelectronics strongly demand high-performance solution-processable semiconductor materials as well as the methods for tuning their functionalities. , Conjugated small molecules, being among the most efficient molecular semiconductors, attracted reasonable attention due to their condensed π-systems, known crystalline structures, variability, high charge carrier mobility, and outstanding optical properties. − A number of approaches for tuning their crystalline structure and optical and charge transport properties , were elaborated; variation of an sp 2 -hybridized carbon skeleton framework and conjugation length, − annulation, , introduction of substituents, − heterojunctions, , polymorphism − and specific crystallizations ,− were previously discovered and extensively studied. Polymorphism is one of the powerful tools in material science for understanding the structure–property relationship and controlling the properties without changing the molecular structure. − Crystallization control by the variation of the solvent system, kinetics, and methodology is also among the most efficient approaches within the field, allowing one to tune the optoelectronic performance without time- and effort-consuming chemical synthesis. − Therefore, the development of a specific and efficient crystallization method is strongly necessary for organic semiconductors.…”

Crystal Structure, Hirshfeld Surface Analysis and Energy Framework Calculations of Different Metal Complexes of a Biphenol-based Ligand: Role of Solvent and Transition Metal Ion

“…The employment of different crystallization solvents can produce indeed different crystal forms, where the solvent molecules could affect the solid state assembly [4,5]. The effect of the solvent can indeed influence the growth, the morphology and the packing of crystal structures [6][7][8][9][10][11][12][13][14], so that the same ligand can crystallize in different forms [4].…”