Fabrication of SiOC ceramic microparts and patterned structures from polysiloxanes via liquid cast and pyrolysis

Abstract

SiOC ceramic microparts and patterned microstructures are fabricated from their metal masters using polysiloxanes as a precursor, which consists of polyhydromethylsiloxane (PHMS) and 1,3,5,7-tetramethyl-1,3,5,7- tetravinylcyclotetrasiloxane (D4Vi), via mold transfer, liquid cast, crosslink, and pyrolysis. The mixed liquid of PHMS and D4V was cast with the polydimethylsiloxane (PDMS) negative molds transferred from the masters and solidified via hydrosilylation of PHMS and D4Vi under controlled heating. Because both the precursors and mold materials are polysiloxanes, their chemical similarities ensure the excellent contact between the two phases that allows for the precise duplication of the master microstructures into the polysiloxanes. Strategies were developed for the use of a two-step controlled heating method and the use of polysiloxane as a support in the processes of demolding, crosslinking, and pyrolysis in order to ensure the bonding qualities of both the crosslinked bodies and the pyrolyzed microstructures. Through this route, we obtained dense and crack-free SiOC ceramic microngears and arrayed holes of well-duplicated microstructures with a resolution down to the submicrometers. Moreover, the polysiloxanes allow the direct imprints with the metal masters to form inversed microstructures of SiOC ceramics, as demonstrated by the formation of microchannels and various motifs of SiOC ceramics from their metal counterparts. © 2008 The American Ceramic Society.