(303q) A Comparative Analysis of the Influence of Macromolecular Templates on the Growth of Calcium Carbonate Crystals Using a Droplet-Based Microfluidic System

Biomineralization is the process by which living organisms produce minerals, often in intricate and highly organized structures. Biominerals are complex inorganic-organic composites, and they have various sizes ranging from millimeters to nanometers. One of the most common biominerals is calcium carbonate (CaCO₃), which is often found in a wide range of organisms, from marine mollusks to human bones. Living organisms use biomolecular controls to create biominerals exhibiting complex hierarchical structures. The challenge is to link macromolecule-crystal interaction to changes in kinetics, growth mechanism, size, and shape.

The crystal growth of calcium carbonate is a complex process that is influenced by a variety of physical and chemical controls, including temperature, pH, and the presence of other additives in the solution environments. In recent years, there has been increasing interest in studying the crystal growth of calcium carbonate under microfluidic environments, which can provide precise control of the flow and composition of the fluid. The use of microfluidics has the potential to provide new insights into the mechanisms of biomineralization and to facilitate the development of new materials with tailored properties.

Herein, we synthesized a category of polymers, including hyperbranched polymers (HBPs), derivatized with functional groups such as carboxyl acids and amine moieties that have a relatively strong electrostatic interaction with cationic Ca²⁺ and anionic CO₃^2- ions. To gain insights into the interactions between crystals and functional macromolecules, we conducted a comparative study on the influence of macromolecular templates on the growth of calcium carbonate crystals using both a bulk and a droplet-based microfluidic system. We obtained information such as nucleation density, crystal number density, and polymorphs of the crystals from growth kinetics via various analytical methods, including in situ optical microscopy equipped with a high speed CCD camera. The results of CaCO₃ crystal formation mediated by functional macromolecular templates under the bulk and microfluidic environments will be discussed in the presentation.