(750f) Engineering the Biomimetic Mineralization Process Via Microscale Ultra-Homoporous Membrane Crystallizer

Precise control of biomimetic mineralization is a major concern in crystal nucleation and biochemical related research. Herein, we propose a novel microscale interfacial crystallizer with nanoscale ultra-homo through-channel to realize the high selective synthesis of CaCO₃ superstructures via simulating the Gas-Liquid interfacial reactive crystallization. The constructed crystallizer possessing the tunable interfacial nucleation surface energy was attributed to the synergetic strengthening of interfacial roughness structure and fluorine-containing groups. The surface nuclear energy could be controlled in the range of 71.28 to 1.32 mJ/m². The nanoscale ultra-homo pore with adjustable nucleation energy render the droplet on the interfacial crystallizer with ultra-homo nucleation cite and sufficient diffusion condition during the fast reactive crystallization, which resulting in the high selective construction of complex CaCO₃ superstructures and obtaining three kinds of typical crystal morphologies (cubic, polyhedron and sphere).

In addition, the regulation of CO₂ gas flow rate in the through-channel of crystallizer can be conveniently achieved and determine the spatial distribution of nucleation and cluster diffusion, which also resulting in the formation of CaCO₃ superstructures with different morphologies. The proportion of spherical and polyhedral crystals increased by 6 times with the reduction of surface energy in CO₂ atmosphere, and the crystal size distribution of the crystals was uniform (C.V. ≤18%). Thus, compared with the classical nucleation theory, biomimetic mineralization using the ultra-uniform 200 nm level channel was coordinately regulated by the microenvironment of multi-scale crystallizer, which showed higher control precision and the mixing scale and efficiency were improved by 1 orders of magnitude. Based on the classic Hagen Poiseuille transfer model, it is confirmed that the mixing and diffusion efficiency of the developed multi-scale crystallizer is significantly improved.

Fig. 1. Effect of gas flow rate on crystallization: schematic diagram of crystallization on ulta-homoporous membrane crystallizer (A); Representative CaCO₃ crystal morphologies obtained at different gas flow rates: 3.69×10^-5 m/h; 2.03×10^-4 m/h; 4.06×10^-4 m/h; 4.06×10^-3 m/h (B); Mapping of representative CaCO₃ crystal morphologies at low gas flow rates (3.69×10^-5 m/h)(C); Ratio distribution of CaCO₃ crystals with different morphologies at different gas flow rate (D).

Acknowledgement

We acknowledge the financial contribution from National Natural Science Foundation of China (Grant No. 21676043, 21527812, U1663223, 21978037), MOST innovation team in key area (No. 2016RA4053) and Fundamental Research Funds for the Central Universities (DUT19TD33).