Fabrication of hierarchically porous materials and nanowires through coffee ring effect

Sachin Khapli, Ina Rianasari, Thomas Blanton, James Weston, Rachael Gilardetti, Rodrigo Neiva, Nick Tovar, Paulo G. Coelho, Ramesh Jagannathan

Research output: Contribution to journalArticlepeer-review


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 ∼3 μm) deposited from an aerosol onto heated substrates (T = 120 °C). A variety of porous scaffolds with 1-3 μm 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 (∼50 nm and 1-3 μm). 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.

Original languageEnglish (US)
Pages (from-to)20643-20653
Number of pages11
JournalACS Applied Materials and Interfaces
Issue number23
StatePublished - Dec 10 2014


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

ASJC Scopus subject areas

  • General Materials Science


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