Laser-defined graphene strain sensor directly fabricated on 3D-printed structure

Abstract

A direct-write method to fabricate a strain sensor directly on a structure of interest is reported. In this method, a commercial graphene ink is printed as a square patch (6 mm square) on the structure. The patch is dried at 100 °C for 30 min to remove residual solvents but the printed graphene remains in an insulative state. By scanning a focused laser (830 nm, 100 mW), the graphene becomes electrically conductive and exhibits a piezoresistive effect and a low temperature coefficient of resistance of −0.0006 °C−1. Using this approach, the laser defines a strain sensor pattern on the printed graphene patch. To demonstrate the method, a strain sensor was directly fabricated on a 3D-printed test coupon made of ULTEM 9085 thermoplastic. The sensor exhibits a gauge factor of 3.58, which is significantly higher than that of commercial foil strain gauges made of constantan. This method is an attractive alternative when commercial strain sensors are difficult to employ due to the high porosity and surface roughness of the material structure under test.

Laser sintering of printed silver thin films for fabrication of strain sensors directly on a structure

“…It is compatible with any printable sensing material that requires post-print thermal sintering to be electrically conductive. An example of such material that has been explored is a graphene ink [7]. By scanning the laser in a controlled fashion over a film printed from such ink, conductive patterns on the film can be generated.…”

Conductivity effects on printed RF interconnects due to printed dielectric ramps

“…where  is the cross section area of the trace and L is the separation distance between the line electrodes used to measure the voltage drop. This technique of measuring  for narrow and straight printed traces has already been described from previous work [16]. Three commercially available Ag inks were investigated as electrical interconnects printed on the NEA-121 structures.…”

Laser-Induced Graphene Strain Sensor for Conformable Lip-Reading Recognition and Human–Machine Interaction

“…Graphene has recently emerged as a promising sensing material owing to its excellent mechanical and electrical properties. , To commercialize graphene, various synthesis protocols have been developed, including mechanical exfoliation, chemical vapor deposition, and chemical reduction of graphene oxide. − These methods have the advantage in manufacturing graphene of different grades, and they also present challenges, such as nonscalable production, high energy consumption, and massive waste generation . Laser-induced technology has been recognized as a powerful approach for high-throughput, precisely programmable, and mask-free fabrication of various electronics, such as wearable strain sensors, heterostructure transistors, and flexible electrochemical sensors. ,− Laser-induced graphene (LIG) on polyimide (PI) substrates has also been explored for patterned strain sensors, achieving controllable physical and electrical properties and tailorable sensitivities , by precisely controlling laser power, speed, and atmosphere. , Herein, we propose a flexible lip-reading strain sensor based on the LIG. To capture the motion information of lip muscles and convert it into electrical signals that can be processed by a computer (Figure a), we investigate the performance of the strain sensor under different bending and pressing conditions and examine the effects of different laser parameters on its sensing capabilities.…”