Gao, Y.C.; Qin, B.; Wen, S.M.; You, Y.; Xue, J.Z.; Yin, Y.C.; Ma, Z.Y.; Dong, K.; Meng, Y.F.; Manke, I.; Zhang, S.C.; Yu, Z.L.; Yu, S.H.: Ambient Pressure Drying of Freeze-Cast Ceramics from Aqueous Suspension. Nano Letters 23 (2023), p. 9011-9019
10.1021/acs.nanolett.3c02654
Abstract:
Freeze-casting has been wildly exploited to construct porous ceramics but usually requires costly and demanding freeze-drying (high vacuum, size limit, and supercooled chamber), which can be avoided by the ambient pressure drying (APD) technique. However, applying APD to freeze-cast ceramic based on an aqueous suspension is still challenging due to inert surface chemistry. Herein, a modified APD strategy is developed to improve the drying process of freeze-cast ceramics by exploiting the simultaneous ice etching, ionic cross-linking, and solvent exchange under mild conditions (-10–0 °C, ambient pressure). This versatile strategy is applicable to various ceramic species, metal ions, and freezing techniques. The incorporated metal ions not only enhance liquid-phase sintering, producing ceramics with higher density and mechanical properties than freeze-cast counterparts, but also render customizable coloration and antibacterial property. The cost-/time-efficient APD is promising for mass production and even successive production of large-size freeze-cast ceramics that exceed the size of commercial freeze-dryers.