Synthesis of Submicron CaCO₃ Particles in 3D-Printed Microfluidic Chips Supporting Advection and Diffusion Mixing

Area of Science:

• Materials Science
• Chemical Engineering
• Nanotechnology

Background:

• Microfluidic technology offers precise control over chemical reactions and particle synthesis.
• Continuous synthesis of calcium carbonate (CaCO3) particles, particularly in the vaterite form, presents challenges in controlling size and morphology.
• 3D-printed microfluidic chips provide a customizable platform for microscale fluid manipulation.

Purpose of the Study:

• To investigate a continuous one-phase synthesis method for CaCO3 micro- and nanoparticles using a 3D-printed microfluidic chip.
• To explore the influence of different synthesis regimes on particle characteristics.
• To achieve controlled production of vaterite CaCO3 particles, including submicron and nanoscale sizes.

Main Methods:

• Utilized a 3D-printed microfluidic chip with a 2 mm² channel cross-section for continuous CaCO3 synthesis.
• Employed confocal and scanning electron microscopy (SEM) for morphological analysis.
• Applied Raman spectroscopy for polymorph composition evaluation.
• Investigated two distinct synthesis regimes: chaotic advection and diffusion mixing.

Main Results:

• Identified two synthesis regimes within the microfluidic chip.
• Chaotic advection regime produced ~2 μm CaCO3 particles with broad size distribution.
• Diffusion mixing regime yielded submicron (800-900 nm) and nanoscale (70-80 nm) vaterite particles.
• Demonstrated successful synthesis of vaterite CaCO3 across a range of sizes.

Conclusions:

• 3D-printed microfluidic chips enable continuous, controlled synthesis of CaCO3 micro- and nanoparticles.
• The identified synthesis regimes allow for tailoring particle size and morphology.
• This work advances microfluidic synthesis for controlled nanomaterial production.