Due to complicated manufacturing methods and lack of machinability, the use of engineering ceramics is limited by the manufacturing processes used to fabricate parts with intricate geometries. The 3D printing of polymers that can be pyrolyzed into functional ceramics has recently been used to significantly expand the range of geometries that can be manufactured, but large shrinkage during pyrolysis has the potential to lead to cracking. In this work, a method to additively manufacture particle‐reinforced ceramic matrix composites is described. Specifically, stereolithography is used to crosslink a resin comprised of acrylate and vinyl‐functionalized siloxane oligomers with dispersed SiC whiskers. After crosslinking, the part is pyrolyzed to amorphous SiOC while the SiC whiskers remain unaffected. Composite ceramics shrink 37% while unreinforced parts shrink 42%; this significant reduction in shrinkage improves part stability. Importantly, these ceramic matrix composites contain no visible porosity nor cracking on the microstructural level. With the introduction of SiC, hardness increases from 10.8 to 12.1 GPa and density decreases from 2.99 to 2.86 g cm−3. Finally, printed ceramic porous structures, gears, and components for turbine blades are demonstrated. Applying stereolithographic techniques to ceramic matrix composites, this work may improve processing and properties of ceramics for applications that require complex geometries.

This study explores the functionalization of main-chain nematic elastomers with a conductive metallic surface layer using a polydopamine binder. Using a two-stage thiol-acrylate reaction, a programmed monodomain was achieved for thermo-reversible actuation. A copper layer (∼155 nm) was deposited onto polymer samples using electroless deposition while the samples were in their elongated nematic state. Samples underwent 42% contraction when heated above the isotropic transition temperature. During the thermal cycle, buckling of the copper layer was seen in the direction perpendicular to contraction; however, transverse cracking occurred due to the large Poisson effect experienced during actuation. As a result, the electrical conductivity of the layer reduced quickly as a function of thermal cycling. However, samples did not show signs of delamination after 25 thermal cycles. These results demonstrate the ability to explore multi-functional liquid-crystalline composites using relatively facile synthesis, adhesion, and deposition techniques.

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