Crack‐Free Drying of Ceramic Microparts on a Hydrophobic Flexible Polymer Substrate Using Soft Lithography

Abstract

Drying is a critical step in the fabrication of ceramic microparts from suspensions using soft lithography. In this communication, a simple method using a hydrophobic flexible polymer substrate was demonstrated to avoid the formation of cracks within ceramic microparts. Crack-free alumina green microchannel parts with 120 lm feature size were attained on a polyethylene film. The results show that both the hydrophobic and flexible properties of the polymeric substrates can remove the substrate constraint to the green body of micropart, which is capable of preventing cracks formation. The method can be used to fabricate ceramic microparts/micropatterns for microeletromechanical systems and functional thick ceramic films.H. Hassanin-contributing editor Manuscript No. 37982.

Effect of surrounding polydimethylsiloxane frame and substrate on drying behavior of aqueous alumina suspensions

“…Duramax D‐3019 (Rohm and Haas, Philadelphia, USA) was used as the dispersant. The suspensions were prepared as described elsewhere . Briefly speaking, the dispersant was firstly dissolved in deionized water.…”

“…The suspensions were prepared as described elsewhere. 16 Briefly speaking, the dispersant was firstly dissolved in deionized water. After gradually adding the powder with stirring to the solution, the pH value was adjusted to 11.0 with 25% NH 4 OH (aq).…”

“…However, it is difficult to remove the organic additives without any introduced defects through sintering. The others are achieved using cosolvent, deformable substrate, or special drying methods such as increasing the humidity and supercritical drying . These methods are usually limited by expensive equipment, high cost, and complicated operations.…”

“…In our previous work, we have fabricated alumina microchannel parts from a high solid content suspension using microtransfer molding, and have found that crack‐free alumina microsized structures could be obtained by drying the suspension on a polyethylene (PE) film substrate. It is supposed that the tensile stress generated in the body during drying could be released by both of the flexible hydrophobic polydimethylsiloxane (PDMS) mold and PE film substrate, that is, the hydrophobic PE film significantly decreases the substrate constraint on the body and both of the flexible PDMS mold and PE film release the tensile stress.…”

Mechanical behaviour of polymer derived ceramics – a review

“…Recent developments in advanced processing technologies such as lithography, spin on nanoprinting technique, 3-D printing, focused ion beam, etc. have contributed to the manufacturing of these microcomponents [120][121][122][123][124][125][126][127][128]. Figure 4 shows intricate nanostructures of size less than 100 nm fabricated by focused ion beam technique [128].…”