Fabrication Of Conductive Patterns Research Articles

Fabrication of Low Electrical Percolation Threshold Multi-Walled Carbon Nanotube Sensors Using Magnetic Patterning

Soft robotics is an expanding area with multiple applications; however, building low-cost, soft, and flexible robots requires the development of sensors that can be directly integrated into the soft robotics fabrication process. Thus, the motivation for this work was the design of a low-cost fabrication process of flexible sensors that can detect touch and deformation. The fabrication process proposed uses a flexible polymer nanocomposite with permanent magnets strategically placed where the conductive electrodes should be. The nanocomposite is based on poly(dimethylsiloxane) (PDMS) and multi-walled carbon nanotubes (MWCNTs). The MWCNT contains ferromagnetic impurities remaining from the synthesis process, which can be used for magnetic manipulation. Several electrode geometries were successfully simulated and tested. The magnetic patterning was simulated, allowing the fabrication of conductive patterns within the composite. This fabrication process allowed the reduction of the electrical resistivity of the nanocomposites as compared to the composites with homogeneous MWCNT dispersion. It also allowed the fabrication of piezoresistive and triboelectric sensors at MWCNT concentration as low as 0.5 wt.%. The fabrication process proposed is flexible, allows the development of sensors for soft robotics, as well as monitoring large and unconventional areas, and may be adapted to different mould shapes and polymers at low cost.

Multi-sensor feedback control for the flash sintering of printed nano-silver ink

The fabrication of conductive patterns using the flash sintering of nano-silver ink has advantages such as high production efficiency and low process temperature. However, the stability of flash-sintered conductive patterns is questionable owing to the vulnerable surface morphology. To improve stability, this study proposes an online sintering state monitoring method using feedback control based on multi-sensor data. The flash-sintered conductive patterns exhibit different surface morphologies at different sintering states. To determine the degree of sintering, an imaging system is implemented to analyze the near-infrared light reflections from the conductive patterns. Meanwhile, a non-contact thermometer is used to measure the temperature difference between the conductive patterns and the substrate. Since the thermal conductivity of the conductive pattern changes during flash sintering, the temperature difference can represent the degree of sintering. By combining the near infrared image and temperature data, the sintering state can be accurately evaluated, and the sintering parameters can be optimized to achieve closed-loop flash sintering. As an example, this method was successfully applied to fabricate microstrip antenna arrays whose return loss and antenna gain are consistent with performances of conventional screen-printed microstrip antenna.

Fabrication of Conductive Patterns on 3D Printed Structure Using Photo‐Polymerization Technology

3D printing technology is attracting considerable attention as it can be used to produce complex‐shaped structures quickly. Recently, in addition to the production of simple‐shaped parts, the manufacturing of embedded products with conductive patterns using 3D printing has increased. However, previous studies have limitations on conductivity, stability, and process complexity. Therefore, in this paper, a novel manufacturing process is proposed. It uses the same laser energy source of photo‐polymerization technology, which is a general 3D printing technology, to create a circuit pattern with high conductivity immediately after the structure is printed. This concept is based on two technologies: a laser direct structuring process and metal photo‐polymerization. Moreover, with this technique, it is possible to produce structures and conductive patterns using a single laser‐based machine. Therefore, alignment tolerance can be ignored during production. After additional metal deposition, the structure can achieve stable and high conductivity. The pattern produced by this novel manufacturing process has a resistance of 0.5 Ω cm–1, and the feasibility of the circuit is illustrated with a light‐emitting diode demonstration. This method is expected to be helpful for both shape production and the development of products that perform electrical functions.

Fabrication of Conductive Patterns on Organic Film with Copper Nano-Ink

Fabrication of Conductive Patterns on Organic Film with Copper Nano-Ink