Molding ceramic microstructures on flat and curved surfaces with and without embedded carbon nanotubes

This paper explores micromolding fabrication of alumina ceramic microstructures on flat and curved surfaces, the transfer of carbon nanotube (CNT) micropatterns into the ceramic and oxidation inhibition of these CNTs through ceramic encapsulation. Microstructured master mold templates were fabricated from etched silicon, thermally embossed sacrificial polymer and flexible polydimethylsiloxane (PDMS). The polymer templates were themselves made from silicon masters. Thus, once the master is produced, no further access to a microfabrication facility is required. Using the flexible PDMS molds, ceramic structures with mm scale curvature having microstructures on either the inside or the outside of the curved macrostructure were fabricated. It was possible to embed CNTs into the ceramic microstructures. To do this, micropatterned CNTs on silicon were transferred to ceramic via vacuum molding. Multilayered micropatterned CNT-ceramic devices were fabricated, and CNT electrical traces were encapsulated with ceramic to inhibit oxidation. During oxidation trials, encapsulated CNT traces showed an increase in resistance that was 62% less than those that were not encapsulated. The processes described here could allow fabrication of inexpensive 3D ceramic microstructures suitable for high temperature and harsh chemical environments.