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Advanced nanomaterials and novel microstructures have been developed to achieve flexible piezoresistive pressure sensors with high sensitivity and wide linearity range. However, the theoretical relationships between the sensitivity and the structure of the flexible pressure sensor have rarely been established. Consequently, the sensitivities of the sensors cannot be controlled and tailored for practical application. In this work, a skin‐inspired flexible pressure sensor with gradient porous structure is proposed. Based on the stress distribution of finite element analysis (FEA), the quantitative descriptions between the sensitivity and sensor structure parameters are derived. Then, carbon black (CB)/polydimethylsiloxane (PDMS) composites are successfully fabricated with desired gradient porous structures by 3D printing technology. Encouragingly, the skin‐inspired gradient structure sensor shows good sensitivity (0.0048 kPa−1) over the ultrawide linear range of 0–500 kPa. Meanwhile, the sensor shows excellent stability and durability during over 500 compression cycles. Taking advantage of these excellent sensing properties, the skin‐inspired gradient porous sensor is demonstrated in the application of voice recognition, grasp sensing, and intermittent pneumatic compression (IPC) interface pressure monitoring. [ABSTRACT FROM AUTHOR]

In this paper, the electrohydrodynamic (EHD) printing method for the flexible electronics with nanosilver ink was studied. The effect of DC voltage and air pressure on the printed nanosilver line was experimentally researched on the printing system. The necessary working voltage was above 600 V DC voltage, and when the voltage reached 1100 V, the line width increased from 1 0 0 μ m to 6 0 0 μ m. The air supply of 1 0 μ L/min resulted an obviously larger width than that of 1 μ L/min , but the printing process was unstable on the 1 0 μ L/min condition. The EHD printing was applied to realize nanosilver ink line ranged from 6 0 μ m to 6 0 0 μ m and a kind of antenna pattern for radio frequency identification devices (RFID) was fabricated. This kind of EHD printing method has the advantages of high flexibility and printing resolution and shows potential prospects in the field of flexible electronics. [ABSTRACT FROM AUTHOR]

In this study, a porous implant model with controllable pores was created, where the pores were distributed with a gradient change from the surface of each pore inwards. The aim was to develop an implant with an elastic modulus of gradient change. The models were subjected to 3D finite element analysis in order to achieve the optimal design parameters. A direct metal laser sintering process was used to print the implant models. Investigations on the physical and mechanical properties revealed that the fabricated implants had a porosity of 65.8–88.2% and an elastic modulus of 12–18 GPa. The property of the sample was close to that of cortical bone. Therefore, the stress shielding effect of the implant and human bone could be reduced. An in vitro cell culture experiment conducted on the samples after surface modification demonstrated that the printed porous parts had good biocompatibility. [ABSTRACT FROM AUTHOR]

Using the 3D printed mold-removal method to fabricate microchannel has become a promising alternative to the conventional soft lithography technique, due to the convenience in printing channel mold and the compatibility with PDMS material. Although having great potential, the use of single filament extruded by fused deposition modeling (FDM) as the sacrificial channel mold has not been elaborately studied. In this paper, we demonstrate the fabrication of microchannels with different structure and size by controllably extruding the sacrificial channel molds. The influences of the main processing parameters including working distance, extrusion amount and printing speed on the printed microchannels are systematically investigated. The results show that, the circular and low-aspect-ratio straight microchannels with different sizes can be fabricated by adjusting the extrusion amounts. The sinusoidal, 3D curved and cross-linked curved microchannels along straight path can be fabricated, either independently or in combination, by the combined control of the working distance, extrusion amount and printing speed. The complex microchannels with different structural features can also be printed along curved serpentine, rectangular serpentine, and spiral paths. This paper presents a simple and powerful method to fabricate the complex microchannels with different structure and size by just controlling the processing parameters for extruding channel molds. [ABSTRACT FROM AUTHOR]

Three-dimensional (3D) printing of ceramics has gained widespread attentions in recent years. Many excellent reviews have reported the printing of ceramics. However, most of them focus on printing of dense ceramics or general ceramic aspects, there is no systematical review about 3D printing of porous ceramics. In this review paper, the 3D printing technologies for fabricating of porous ceramic parts are introduced, including binder jetting, selective laser sintering, direct ink writing, stereolithography, laminated object manufacturing, and indirect 3D printing processes. The techniques to fabricate hierarchical porous ceramics by integrating 3D printing with one or more conventional porous ceramics fabrication approaches are reviewed. The main properties of porous ceramics such as pore size, porosity, and compressive strength are discussed. The emerging applications of 3D printed porous ceramics are presented with a focus on the booming application in bone tissue engineering. Finally, summary and a perspective on the future research directions for 3D printed porous ceramics are provided. [ABSTRACT FROM AUTHOR]