© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 370 wileyonlinelibrary.com COMMUNICATION Stereolithography of SiOC Ceramic Microcomponents Erika Zanchetta, Marco Cattaldo, Giorgia Franchin, Martin Schwentenwein, Johannes Homa, Giovanna Brusatin,* and Paolo Colombo* Dr. E. Zanchetta, M. Cattaldo, G. Franchin, Prof. G. Brusatin, Prof. P. Colombo Department of Industrial Engineering and INSTM University of Padova Via Marzolo 9, 35131 Padova, Italy E-mail: giovanna.brusatin@unipd.it; paolo.colombo@unipd.it Dr. M. Schwentenwein, Dr. J. Homa Lithoz GmbH Mollardgasse 85a/2/64-69, 1060 Vienna, Austria Prof. P. Colombo Department of Materials Science and Engineering The Pennsylvania State University University Park, PA 16802, USA DOI: 10.1002/adma.201503470 by fabricating 3D ceramic microparts through the stereolithog- raphy of preceramic polymers. Polymer-derived-ceramics (PDCs), because of their structure at the nanoscale which is based on Si-rich and carbon-rich nano- sized domains, exhibit enhanced thermomechanical properties with respect to creep and oxidation, crystallization, or phase separation up to 1500 °C and higher, in comparison to several conventional ceramic materials. [27] Moreover, PDCs can possess functional properties such as electrical conductivity, [28] lumines- cence, [29] and piezo-resistivity, [30] coupled with a high chemical durability [31] and favorable noncoagulating behavior in contact with blood [32] as well as compatibility with cells. [33] Because of their physical–chemical and functional properties as well as their ability of being shaped using a wide variety of processing methods, PDCs have found application in several key fields such as information technology, transport, defense, energy as well as environmental systems, biomedical components, sensors, and micro or nanoelectromechanical systems. [34–39] These prece- ramic polymers can be cross-linked in the required shape after forming, using conventional polymer-processing techniques, and finally sintered to give different ceramic phases, such as SiCN, Si 3 N 4 , SiC, SiBCN, and SiOC, depending on the polymer compo- sition and the heating atmosphere. [40] Advanced oxide ceramics can be obtained by the addition of suitable nanosized filler par- ticles to the preceramic polymer. [41] Since PDCs are pyrolyzed at relatively low temperatures (typically, 1000 to 1300 °C), their pro- cessing requires considerably less energy than classical ceramic powder technology, in which sintering is carried at temperatures well in excess of 1600 °C (for SiC and Si 3 N 4 ). As far as microfabrication is concerned, different methods have been used to micropattern PDC components, starting from preceramic polymers. [34] Among them, polysilazane precursors were shaped in 2D using liquid casting and soft- lithography, [35–38,42] or photolithography, [39,43] and were shaped in 3D using nanostereolithography. [44] However, polysilazanes are limited in availability and, more importantly, are sensitive to air, requiring to be processed in a nonmoisture and oxygen-free environment. As a result, the ceramic material resulting from the use is often based on the Si–O–C system. [45] Patterning of polysiloxanes, which are, on the contrary, insensitive to air and moisture, inexpensive, and commercially available in a variety of physical and chemical structures, has been so far obtained only in 2D, using photolithography (for siloxanes containing vinyl groups) or molding techniques. [46–49] Here, we report for the first time on the 3D additive manufacturing of SiOC ceramic microcomponents using an engineered photosensitive methyl-silsesquioxane preceramic polymer ( Figure 1), thereafter referred to as MK-TMSPM, obtained starting from a commercially available silicone (SILRES MK), and an organically modified silicon alkoxide, Nowadays, there is an increasing interest in novel fabrication processes and materials for the realization of 3D microstruc- tures, which otherwise cannot be realized through traditional manufacture technologies, due to their great importance in different technology fields. Many efforts have been devoted so far to 3D patterning of organic polymer or hybrid organic–inor- ganic systems for applications in the semiconductor industry, or as photonic-crystals, microfluidic devices, microelectro- mechanical systems, biochips, and scaffolds for tissue regen- eration. [1–8] However, the general properties of polymers are not sufficient for some applications, and 3D ceramic micro- patterned structures are continuously in-demand for advanced devices working at high temperature or in harsh, corrosive envi- ronments and applications requiring tribological, mechanical, and chemical resistance. [9–14] Selective laser sintering (SLS) [15,16] and 3D printing (3DP) are well known additive manufacturing processes for ceramic powders, [17–19] while stereolithography (SL), laser-based or fusion technologies have been employed to manufacture ceramic components starting from ceramic slurries. [20–22] Other 3D ceramic fabrication processes employ sheets of material, such as laminated object manufacturing (LOM) and computer- aided manufacturing of laminated engineering materials (CAM-LEM). [23–25] However, the procedures using powders and slurries require fine and homogeneously dispersed particles to obtain high resolution and good surface quality, while the ones using material in the form of sheets require the availability of green tapes with high homogeneity, uniform thickness, proper flexibility, and appropriate adhesion. [26] Therefore, the combination of the resolution and surface smoothness of 3D microcomponents, typical of polymer- based techniques, with the chemical, mechanical, and thermal properties of ceramic materials would be a step forward in the 3D ceramic microfabrication field. This combination is possible Adv. Mater. 2016, 28, 370–376 www.advmat.de www.MaterialsViews.com