Laser-induced forward transfer for manufacture of graphite-based heaters on flexible substrate

• Published in: Sensors and actuators. A. Physical. Vol. 373; p. 115442
• Main Authors: Muniraj, Logaheswari, Ardron, Marcus, Fernández-Pradas, Juan M., Duocastella, Martí, Serra, Pere, Reuben, Robert L., Hand, Duncan P.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.08.2024
• Subjects: Direct-write; Graphite heaters; Laser-induced forward transfer; Local heating; Thermal management; Thermal management; Local heating; Graphite heaters; Laser-induced forward transfer; Direct-write
• ISSN: 0924-4247; 1873-3069
• DOI: 10.1016/j.sna.2024.115442

Flexible heaters have recently gained considerable interest owing to their ability to be integrated into a wide variety of miniaturized devices. They are used to perform thermal management, strain engineering, and even electrothermal actuation. These heaters are mainly fabricated using thin film techniques, which typically involves a multi-step lithography process that can be complex and expensive. Alternatively, wet coating methods are also employed; however, these possess several limitations when dealing with high viscosity inks. In this paper, we use a laser driven process called laser-induced forward transfer (LIFT) to fabricate graphite-based heaters on a flexible substrate. LIFT is a non-contact printing process that, unlike ink-jet printing, is nozzle-free, which makes it suitable to print any ink regardless of its viscosity. We report the first use of LIFT to print flexographic graphite ink to pattern heaters. The flexographic ink possesses high viscosity in the order of 1300–1700mPa⋅s. The smallest deposit obtained using the graphite ink was 176 µm in diameter. Characterisation of the heaters shows that they can reach a wide range of temperatures at different voltage inputs. A maximum temperature of 123°C was reached over an area of approximately 18mm2 at 5.2V. [Display omitted] •Fabrication of a graphite heater using laser-induced forward transfer (LIFT).•Ability to print high-aspect ratio structures (tens of µm) at high resolution (176 µm).•Use of flexographic graphite ink to print heaters that provide local heating and temperature control.•Demonstration of temperature control of the heater at different voltage inputs.