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Inspired by the mineralization process of bone, we have investigated mineralization on piezoelectric samples immersed in a solution with mineral ions. We have utilized polyvinylidene fluoride as a piezoelectric material and 10× simulated body fluid as a mineral solution. Three synthetic material systems were developed and characterized using scanning electron microscopy, X-ray diffraction, nanoindentation, and scratch testing. With these techniques, we provide insights into how the characteristics of the mineralization protocol affect the microstructure, chemical composition, crystal structure, and mechanical properties of the minerals. Increasing the solution temperature from 25°C to 50°C resulted in a greater packing density, roughly 10 times the stiffness and 4 times the fracture toughness. Collagen surface treatment resulted in roughly 7 times the stiffness along with potential anisotropy in the fracture toughness. Lastly, calcium phosphate minerals appear to pack in low-density and high-density phases on the piezoelectric scaffolds. 

It is widely known that the printing quality of fused filament fabrication (FFF) is heavily affected by environmental temperature and humidity, taking the form of warping and porosity. However, there is little understanding about the quantitative relations between environmental conditions, geometry, and the mechanical properties of printed parts. In this study, we systematically investigated those relations using bisphenol A polycarbonate as a model material system. For the environmental temperature, an in-situ infrared imaging analysis revealed the presence of an up to 5.4 °C/mm thermal gradient when printing using an open-chamber printer and a heated build plate. For the environmental humidity, an analysis of X-ray micro-computed tomography (micro-CT) scans showed an up to 11.7% porosity that was brought by polymer water content absorbed from environmental moisture. Meanwhile, tensile tests showed a mechanical performance loss associated with those defects, but, surprisingly, the transverse direction ductility had the potential to increase at a higher porosity. Furthermore, the experimental results were combined with analytical and parametrical studies to elucidate quantitative relations between environmental conditions and printing quality. Based on the results, quantitative guidelines for the estimation of printing quality based on environmental conditions are provided that would also help users to obtain desired printing results with a better understanding of the effects of environmental conditions.