Effect of drying conditions on patterned ceramic films processed by soft micromolding

Abstract

A soft lithography technique was used to create patterned green ceramic films including micrometric voids of well-defined geometry. A PDMS mold was filled by high solid content aqueous suspension (4052% vol.) and the process quality as well as the film green density were evaluated through SEM and non-contact profilometry. Drying is a critical step, as limited shrinkage was observed due to wetting of the elastomer by water. The drying conditions were optimized in order to increase the homogeneity and green packing of the structured films. Controlled geometry features of high aspect ratio were produced down to the micrometer scale. There are many technological uses of patterned films. In this study, we have used this approach to introduce controlled flaws and investigate constrained sintering and crack growth.

Shape Distortion and Delamination During Constrained Sintering of Ceramic Stripes: Discrete Element Simulations and Experiments

“…(1) Experimental Procedure A detailed description of the MIMIC method to produce samples including slurry and stamp manufacturing can be found in Refs. (16,17). The measurement of constrained stripe heights was performed using a white light interferometer (ZygoLot GmbH, Darmstadt, Germany).…”

“…Finally, the results of the simulations are compared with measurements. The green ceramic stripes used for the experiments were manufactured using soft micromolding in capillaries (MIMIC), a method that allows producing patterned structures at small scales with relatively high aspect ratios and accuracies …”

Free‐Standing Patterned Ceramic Structures Obtained by Soft Micromolding

“…Smaller holes are even possible. [13] At the same time, the distance d between the single holes is also small; only 10 mm in the green film and 9.41 mm after sintering. This corresponds to an open screening area of % 20%, which is twice the value of electroformed metallic sieves with this opening size.…”

“…Dip-coated layers with a green density of % 68% and deposited on polycrystalline alumina substrates were sintered at 1 350 8C to a final density of 97% after 4 h isothermal time. [25] When the green density is reduced to % 40% by using a diluted suspension, the final density does not exceed 70%, even if heated up to 1 450 8C for 1 h. [13] The green density can be increased by optimizing the drying conditions or by increasing the solid content in the slurry. Continuous coatings deposited by standard methods like spin coating or dip coating from slurries with high solid content enable to reach green densities above 60%.…”

“…[10][11][12] Depending on the targeted density, drying conditions have to be optimized according to the hydrophobic/hydrophilic character of the PDMS mold. [13] After the thermal treatment required for consolidation, sintered structures usually adhere strongly to the underlying substrate. This adhesion can be desired, as in the case of printed electronics for instance.…”