Direct Fabrication of Micron-Thickness PVA-CNT Patterned Films by Integrating Micro-Pen Writing of PVA Films and Drop-on-Demand Printing of CNT Micropatterns

The direct fabrication of micron-thickness patterned electronics consisting of patterned PVA films and CNT micropatterns still faces considerable challenges. Here, we demonstrated the integrated fabrication of PVA films of micron-thickness and CNT-based patterns by utilising micro-pen writing and drop-on-demand printing in sequence. Patterned PVA films of 1–5 μm in thickness were written first using proper micro-pen writing parameters, including the writing gap, the substrate moving velocity, and the working pressure. Then, CNT droplets were printed on PVA films that were cured at 55–65 °C for 3–15 min, resulting in neat CNT patterns. In addition, an inertia-pseudopartial wetting spreading model was established to release the dynamics of the droplet spreading process over thin viscoelastic films. Uniform and dense CNT lines with a porosity of 2.2% were printed on PVA substrates that were preprocessed at 55 °C for 9 min using a staggered overwriting method with the proper number of layers. Finally, we demonstrated the feasibility of this hybrid printing method by printing a patterned PVA-CNT film and a micro-ribbon. This study provides a valid method for directly fabricating micron-thickness PVA-CNT electronics. The proposed method can also provide guidance on the direct writing of other high-molecular polymer materials and printing inks of other nanosuspensions.

The Liver

This chapter reports on efforts to bioprint liver tissue, including the important types of liver cells and also the liver’s cytoarchitecture—the typical pattern of cellular arrangement within liver tissue. The chapter gives an account of the liver’s remarkable regenerative ability, its over 500 vital functions, its unusual blood supply, and the difficulty of growing liver cells in vitro (in the laboratory). The chapter includes a description of a hybrid printing/casting method employing human hepatocytes (liver cells) encapsulated in a hydrogel called a “liver tissue seed.” Implanted into mice with a liver injury, the seed tissue provided functional support to the failing liver and expanded in size by 50-fold over the course of 11 weeks. The chapter also mentions Organovo, the first commercial bioprinting company and a pioneer in bioprinting commercially available human tissues, notably their lead product, liver tissue.

Preparation and Characterization of Printed LTCC Substrates for Microwave Devices

A novel LTCC substrate manufacturing process based on 3D printing was investigated in this paper. Borosilicate glass-alumina substrates with controlled size and thickness were successfully manufactured using a self-developed dual-nozzle hybrid printing system. The printing parameters were carefully analyzed. The mechanical and dielectric properties of the printed substrate were examined. The results show that the printed substrates obtain smooth surface (Ra=0.92 μm), compact microstructure (relative density 93.7%), proper bending strength (156 mPa), and low dielectric constant and loss (Ɛr=6.2, 1/tan⁡δ=0.0055, at 3 GHz). All of those qualify the printed glass–ceramic substrates to be used as potential LTCC substrates in the microwave applications. The proposed method could simplify the traditional LTCC technology.