posted on 2021-11-03, 12:33authored byOuassef Nahi, Alexander N. Kulak, Alexander Broad, Yifei Xu, Cedrick OʼShaughnessy, Olivier J. Cayre, Sarah J. Day, Robert Darkins, Fiona C. Meldrum
Soluble
additives are widely used to control crystallization processes,
modifying the morphologies, sizes, polymorphs, and physical properties
of the product crystals. Here, a simple and versatile strategy is
shown to significantly enhance the potency of soluble additives, ranging
from ions and amino acids to large dye molecules, enabling them to
be effective even at low concentrations. Addition of small amounts
of miscible organic co-solvents to an aqueous crystallization solution
can yield enhanced morphological changes and an order of magnitude
increase of additive incorporation within single crystalsa
level that cannot be achieved in pure aqueous solutions at any additive
concentration. The generality of this strategy is demonstrated by
application to crystals of calcium carbonate, manganese carbonate,
and strontium sulfate, with a more pronounced effect observed for
co-solvents with lower dielectric constants and polarities, indicating
a general underlying mechanism that alters water activity. This work
increases the understanding of additive/crystal interactions and may
see great application in industrial-scale crystal synthesis.