(102a) Tailoring Material Properties Using Additive Manufacturing Techniques

Direct ink write (DIW) is a commonly used technique in polymer additive manufacturing, where filaments of material are deposited to build 3D structures. The development of desktop robotic arms have enabled the capability for conformal and support free printing within the DIW field; However, the research on the effects of printing with a robotic arm vs a gantry system on the material properties is limited. We investigated the effects of DIW with a robotic arm on the printability and material properties of an anisotropic material as compared to a gantry system. Using a carbon fiber epoxy composite ink, samples were mechanically tested, 3D scanned to investigate geometrical accuracies, and CT scanned to analyze fiber alignment to elucidate the role of nozzle orientation, kinematics, and gravity on the material properties. This research will provide insight into deposition technique effects on material properties, providing a better understanding of printing onto complex surfaces. Then, we will present a methodology to realize surface-templated homeotropic orientation in liquid crystal elastomers and omnidirectional nonlinearity in mechanical deformation. Liquid crystalline elastomers (LCEs) are widely recognized for their exceptional promise as actuating materials that can be utilized in aerospace applications, optics, or medicine. By inkjet printing the homeotropic alignment surface, we can localize regions of homeotropic and planar orientation within a monolithic LCE element. The local control of the self-assembly and orientation of the LCE yields materials with discontinuous mechanical deformation but with the advantage of lacking material–material interfaces, a common source of failure. This allows us the ability to create designer functional monoliths with tunable Poisson's ratios which may find use in many applications such as flexible hybrid devices.