(468c) Selective Construction of CaCO3 Superstructures Via Homoporous Interfacial Crystallizer

Xiaobin Jiang, Mengyuan Wu, and Gaohong He

Abstract

Biomimetic mineralization and crytallization for highly ordered superstructures is one of the key concerns in crystal engineering. Herein, we propose a ultra-homoporous interfacial crystallizer (UHIC) as a novel interfacial microdevice, which has realized high selective synthesis of CaCO₃ superstructures during Gas-Liquid reactive crystallization process. This UHIC with ultra-uniform mass transfer porous channel and interfacial superhydrophilicity render the droplet ultra-homo nucleation site and coordinatively regulate the interfacial nucleation energy. In addition, based on the classic Hagen Poiseuille transfer model, the mixing and diffusion efficiency of the developed multi-scale crystallizer can be significantly intensified when the mass transfer scale decreased to the ultra-uniform 200 nm level (shown in Fig. 1). The proposed interfacial crystallizer was functioning as the aggregation of thousands of parallel microchannels (approximate 6´10⁶ channel/mm²).

The microchannel in UHIC can control the CO₂ gas flow rate and provide sufficient interfacial diffusion of the CaCO₃ pre-nucleation cluster (PNC). By coordinating the PNC diffusion, self-organization and nucleus growth, the synthesised CaCO₃ crystals with spherical and polyhedral structures both increased to higher than 96.77 %, and the particle size distribution was very uniform (C.V. =11.7%). UHIC can engineer the biomimetic mineralization procedure by coordinatively regulating the interfacial nucleation at the sub-micron porous channels, which may shed light on the development of material science and crytal engineering.

Fig. 1. Interfacial mixing time (t_{mix, G} for gas phase and t_{mix, L} for liquid phase) of CO₂ versus Reynolds number in different microscale devices (UHIC, classic T-Mixer, crystal kettle).