Versatile Crack‐Free Ceramic Micropatterns Made by a Modified Molding Technique

Abstract

Crack‐free ceramic micropatterns made of oxidic ceramic powders, e.g. alumina, titania, zirconia, and nonoxidic calciumphosphate ceramic powders were fabricated by a novel, simple, and low‐cost modified micromolding (m‐μM) technique via polydimethylsiloxane stamps. By means of this m‐μM technique it is possible to fabricate monolithic ceramic bodies with a micropatterned surface with very high accuracy on surface detail. Our produced micropatterns can feature various geometries, e.g. cylinders, holes, channels, and struts with diameters ranging from 8 to 140 μm in diameter or widths and from 8 to 30 μm in depth or height. The oxidic and nonoxidic ceramic micropatterns could be removed from the molds and dried without any cracks. Even after sintering, these micropatterned samples showed no cracks or fissures. The reported technique has a very high potential for fully automatized up‐scale fabrication of micropatterned ceramic surfaces.

Micromolding of Calcium Carbonate Using a Bio‐Inspired, Coacervation‐Mediated Process

“…All experiments were carried out using double deionized water with a conductivity of 0.04 μS/cm obtained from a Synergy ® apparatus (Millipore, Darmstadt, Germany). The molding forms (PDMS, Sylgard ® 184 silicone elastomer, Dow Corning, Wiesbaden, Germany) were prepared as described in the literature …”

Enzyme-assisted calcium phosphate biomineralization on an inert alumina surface

“…Planar alumina discs were fabricated using a modified micromoulding method described in Holthaus et al [23]. Alumina aqueous suspensions (solid content of 20 vol.%) were obtained by mixing 19.9 g particles with 20 ml ddH 2 O. Polyacrylic acid (1.2 vol.%) was used as binder.…”

ZnO Submicrometer Rod Array by Soft Lithographic Micromolding with High Solid Loading Nanoparticle Suspension

“…The effect of air diffusion on the fidelity of soft lithographic micromolding remains unknown. For the micromolding liquid, colloidal suspensions of nanoparticles are preferred to increase the solids loading, desirably to as high as 40 vol% . Electrostatic stabilization by adjusting the surface charge of the nanoparticles and steric stabilization by adsorbing polymer dispersants on nanoparticle surfaces can be utilized to overcome nanoparticle agglomeration and high suspension viscosity .…”

“…[6][7][8][9] Soft lithography offers a novel and effective approach to create ceramic patterns with micro-to nanostructures. [10][11][12][13][14][15][16][17][18][19][20][21][22] Microelectromechanical systems (MEMS) based on ceramic materials have been successfully achieved by soft lithography. [14][15][16][17] For example, complicated borosilicon carbonitride (SiBNC) MEMS devices with 20-100 lm dimensions have been obtained by microtransfer molding 14 ; the structural integrity of MEMS Al 2 O 3 ceramics has been further enhanced by centrifugally aided micromolding 15 ; parallel SiCN microlines several millimeters in length have been created by micromolding in capillaries with ceramic precursors.…”

“…For the micromolding liquid, colloidal suspensions of nanoparticles are preferred to increase the solids loading, desirably to as high as 40 vol%. [11][12][13][23][24][25][26] Electrostatic stabilization by adjusting the surface charge of the nanoparticles and steric stabilization by adsorbing polymer dispersants on nanoparticle surfaces can be utilized to overcome nanoparticle agglomeration and high suspension viscosity. 24,27,28 However, the ability of the nanoparticle suspension to push the fabrication scale into the submicrometer range needs to be further explored.…”