Application of Polymers as a Tool in Crystallization—A Review

Abstract

The application of polymers as a tool in the crystallization process is gaining more and more interest among the scientific community. According to Web of Science statistics the number of papers dealing with “Polymer induced crystallization” increased from 2 in 1990 to 436 in 2020, and for “Polymer controlled crystallization”—from 4 in 1990 to 344 in 2020. This is clear evidence that both topics are vivid, attractive and intensively investigated nowadays. Efficient control of crystallization and crystal properties still represents a bottleneck in the manufacturing of crystalline materials ranging from pigments, antiscalants, nanoporous materials and pharmaceuticals to semiconductor particles. However, a rapid development in precise and reliable measuring methods and techniques would enable one to better describe phenomena involved, to formulate theoretical models, and probably most importantly, to develop practical indications for how to appropriately lead many important processes in the industry. It is clearly visible at the first glance through a number of representative papers in the area, that many of them are preoccupied with the testing and production of pharmaceuticals, while the rest are addressed to new crystalline materials, renewable energy, water and wastewater technology and other branches of industry where the crystallization process takes place. In this work, authors gathered and briefly discuss over 100 papers, published in leading scientific periodicals, devoted to the influence of polymers on crystallizing solutions.

Acrylate and Methacrylate Polymers’ Applications: Second Life with Inexpensive and Sustainable Recycling Approaches

“…Conversely, high amount of PAA covers the nucleation sites on ACP surface, changing the morphology of ACP and blocking the HA crystallization process. The ability of PAA to influence HA crystallization could be an interesting tool to regulate the development and the properties of bone substitutes [ 130 ].…”

Ammonio Methacrylate Copolymer (Type B)-Diltiazem Interactions in Solid Dispersions and Microsponge Drug-Delivery Systems

“…Compared to the solid crystalline dispersions, the solid amorphous drug–polymer dispersions are characterized by increased homogeneity, permeability, drug saturation point, and drug release [ 2 ]. Not by accident, the predominantly amorphous-in-nature ammonio methacrylate copolymers (Eudragit ® RS and RL), butylated methacrylate copolymer (Eudragit ® E), and methacrylic acid–methyl methacrylate copolymer 1:1 (Eudragit ® L) [ 6 ] are applied as crystallization inhibitors (both on nucleation and crystal growth) in the composition of miscellaneous drug-delivery carriers [ 7 , 8 , 9 ]. The polymers’ amorphization potency depends on the processing methods and variables and the drug properties; they determine critical qualities of the final product, such as matrix/membrane permeability, porosity, stability, solubility, desorption pattern, etc.…”

Upper Critical Solution Temperature Polymer Phase Transition as a Tool for the Control of Inorganic Salt Crystallization Process

“…The idea is as follows. When the solution is cooled down the solubility of a given substance is decreasing which is depicted by the horizontal arrow in the concentration vs. temperature graph (please note that this research does not concern the revers solubility substances in case of which usually the effort is made to inhibit the nucleation process and prevent scaling phenomenon [ 24 ]). At a certain temperature, the system enters the metastable zone, i.e., the concentration of dissolved matter is higher than it would appear from the solubility curve.…”

“…At the present moment, polymers as tools in crystallization are intensively researched [ 24 ]. They can be used for confined crystallization as specialized microreactors.…”

“…Therefore, the seeding process is usually used in the industry to achieve the nucleation point at the desired point of the metastable zone width (MZW). At the present moment, polymers as tools in crystallization are intensively researched [24]. They can be used for confined crystallization as specialized microreactors.…”