Fabrication of Hierarchically Porous Materials and Nanowires through Coffee Ring Effect

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• 作者：Sachin Khapli ; Ina Rianasari ; Thomas Blanton ; James Weston ; Rachael Gilardetti ; Rodrigo Neiva ; Nick Tovar ; Paulo G. Coelho ; Ramesh Jagannathan
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2014
• 出版时间：December 10, 2014
• 年：2014
• 卷：6
• 期：23
• 页码：20643-20653
• 全文大小：717K
• ISSN：1944-8252

文摘

We report a versatile method for the fabrication of nanowires and hierarchical porous materials from a wide variety of ceramic materials such as CaCO₃, ZnO, CuO, Co₃O₄, Co-doped ZnO, and Ag₂O. The method consists of evaporation of CO₂-enriched water microdroplets (diameter 鈭? 渭m) deposited from an aerosol onto heated substrates (T = 120 掳C). A variety of porous scaffolds with 1鈥? 渭m sized pores can be generated by tuning the process conditions. Subsequent sintering of the scaffolds is shown to generate nanosized pores in the walls of the porous scaffold creating a dual hierarchy of pore sizes (鈭?0 nm and 1鈥? 渭m). We propose a mechanism for the formation of scaffolds based on the coffee-ring effect during the evaporation of microdroplets. Ostwald-ripening of CaCO₃ scaffolds prepared without sintering yields scaffold structures consisting of two-dimensional crystals of CaCO₃ that are one unit cell thick. The favorable application of CaCO₃ scaffolds for the enhancement of bone healing around titanium implants with improved biocompatibility is also demonstrated.r>

Keywords:

bioactive ceramics; hierarchical porous materials; calcium carbonate; two-dimensional crystals; coffee-ring effect