Laser Sintering of Nanocomposite on Flexible Substrate: Experimental Study and Molecular Dynamics Simulation

Flexible electronics involve electronic circuits fabricated on flexible substrates. They have promising applications in wearable devices and flexible sensors etc. and have thus attracted much research interest in recent years. The working environment of flexible electronic devices may require them to go through repeating deformations, during which cracks may generate and grow in the metallic components of the devices, reducing service life of these devices. To address such challenges, it is desirable to investigate methods to improve the reliability of flexible electronics in these working conditions.

This research reported here will focus on topics related to laser-based fabrication of carbon nanotube-metal composites on flexible substrates:

Experimental studies were carried out to investigate the structures and properties of carbon nanotube – metal composites produced by a laser-based fabrication process on flexible substrates. Extensive characterizations and testes were carried out, including measurements of electrical resistivity of laser-sintered material, characterizations with SEM, TEM, EDS and XPS, and mechanical performance tests (bending fatigue test, static tensile test and adhesion test). The experimental study suggests that the laser-fabricated metal composites have promising potentials to help enhancing reliability and durability of metal components in flexible electronic devices.

A molecular dynamics model was also developed to study the coalescence of metal nanoparticles (gold NPs in this study) around the end of a multi-walled carbon nanotube (MWCNT) and their interaction with the CNT at elevated temperatures. The MD model was first tested by comparing the MD-predicted NP melting points with experiment-deduced results from the literature. Then the coalescence of five 3-nm Au NPs around the end of a MWCNT and their interactions with the CNT were studied with MD simulations. The molecular system was studied under different elevated temperatures and for different carbon nanotube diameters, and the simulation results were analyzed and discussed.