Laser-Induced Graphene on Additive Manufacturing Parts.

Additive manufacturing (AM) has become more prominent in leading industries. Recently, there have been intense efforts to achieve a fully functional 3D structural electronic device by integrating conductive structures into AM parts. Here, we introduce a simple approach to creating a conductive layer on a polymer AM part by CO2 laser processing. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Raman spectroscopy were employed to analyze laser-induced modifications in surface morphology and surface chemistry. The results suggest that conductive porous graphene was obtained from the AM-produced carbon precursor after the CO2 laser scanning. At a laser power of 4.5 W, the lowest sheet resistance of 15.9 Ω/sq was obtained, indicating the excellent electrical conductivity of the laser-induced graphene (LIG). The conductive graphene on the AM parts could serve as an electrical interconnection and shows a potential for the manufacturing of electronics components. An interdigital electrode capacitor was written on the AM parts to demonstrate the capability of LIG. Cyclic voltammetry, galvanostatic charge-discharge, and cyclability testing demonstrated good electrochemical performance of the LIG capacitor. These findings may create opportunities for the integration of laser direct writing electronic and additive manufacturing.

Femtosecond Laser Produced Hydrophobic Hierarchical Structures on Additive Manufacturing Parts.

With the recent expansion of additive manufacturing (AM) in industries, there is an intense need to improve the surface quality of AM parts. A functional surface with extreme wettability would explore the application of AM in medical implants and microfluid. In this research, we propose to superimpose the femtosecond (fs) laser induced period surface structures (LIPSS) in the nanoscale onto AM part surfaces with the micro structures that are fabricated in the AM process. A hierarchical structure that has a similar morphology to a lotus leaf surface is obtained by combining the advantages of liquid assisting fs laser processing and AM. A water contact angle (WCA) of 150° is suggested so that a super hydrophobic surface is achieved. The scanning electron microscopy (SEM) images and X-ray photoelectron spectroscopy (XPS) analysis indicate that both hierarchical structures and higher carbon content in the laser processed area are responsible for the super hydrophobicity.