The orthotropic functional properties of additively manufactured ceramics due to the fabrication process was characterized in this study. Spherical, environmentally benign barium titanate (BaTiO 3 ) powders were fabricated using binder jetting 3D printing. Dielectric and piezoelectric properties of these ceramics were characterized as a function of the printing orientation. The dielectric constant of the samples tested normal to the printing layers was observed to be 20% higher than those tested in the parallel fashion. Similarly, the piezoelectric response was found to be over 35% in the normal orientation. With these results, it was shown that the electroding orientation has a direct influence on the functional properties of additively manufactured ceramics. Overall, with less than 37% of the theoretical density, the average piezoelectric coefficient for the perpendicularly tested ceramics was found to be 152.7 pC N −1 , which is 80% of the theoretical value. The high piezoelectric response obtained with such low densities can lead to the development of more mass efficient, and cost-effective sensing and energy harvesting devices, as well as structures that can be tuned to respond based on the direction of the loads applied.

Recent studies have highlighted the effects of various stimuli on the chemical reduction of graphene oxide (GO) through green reductant L-ascorbic acid (L-AA); however, the combination of near ultraviolet (NUV) light to increase the reduction rate has yet to be thoroughly explored. In this study, drop-casted GO films were subjected to chemical reduction through L-AA with various levels of exposure under 405 nm NUV radiation. The structure and uniformity of GO stackings that form the film were characterized through scanning electron microscopy (SEM) and wide-angle x-ray scattering (WAXS). Additionally, WAXS was used to track the removal of oxygencontaining functional groups along with Fourier-transform infrared (FT-IR) spectroscopy and x-ray photoelectron spectroscopy (XPS) as a function of L-AA and NUV light exposure times. XPS results demonstrated that the interaction between L-AA and NUV exposure has a significant effect on the reduction of films. Furthermore, the results that yielded the highest reduction (C-C bond concentration of 60.7%) were the longest L-AA and NUV light exposure times (48 hours and 3 hours, respectively). This report provides a study on the effects of NUV on the green reduction of GO films through L-AA with potential application in solar energy and chemical sensing applications.

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