Radio Frequency Heating of Laser-Induced Graphene on Polymer Surfaces for Rapid Welding

Abstract

In this report, we investigate the rapid heating ability of laser-induced graphene (LIG) in response to radio frequency (RF) fields. Graphitic structures were produced from various industrially prevalent thermoplastics via laser irradiation of the polymer surface. We find that RF responsive, graphitic structures may be produced from Kapton, polyether imide (PEI), polyether sulfone (PESU), polyether ether ketone (PEEK), and polycarbonate (PC) using a conventional laser cutting machine. The graphitic structures are also electrically conductive in addition to being RF responsive. Exposure of LIG to RF fields resulted in the rapid heating of LIG with remarkable heating rates up to 126 °C/s. Finite-element simulations for these systems show similar heating trends. This heating response may be used in advanced manufacturing as a means to rapidly weld polymer–polymer interfaces, as will be demonstrated in this report. Our technique uses RF fields to induce localized heating in contrast to uniform bulk heating from external sources such as ovens or furnaces. The methods detailed in this paper provide a polymer processing pathway that may be used to generate RF responsive filler in situ. Finally, we aim to show that LIG–polymer composites may function in an industrial setting, with particular application to additive manufacturing and functional coatings.

Physical Sensors Based on Laser-Induced Graphene: A Review

“…Radio wave transducers. Inspired by the numerous reports on rapid heating of sp 2 -hybridized carbon nanostructures in response to electromagnetic radiation, Gerringer et al investigated the heating ability of LIG in response to RF fields [93]. The method used RF fields to induce localized heating in contrast to uniform bulk heating from external sources such as ovens or furnaces [145].…”

“…A solid weld was achieved in just 30s of RF exposure. Indeed, localized heat generated during RF field exposure of LIG promoted polymer diffusion and created a weld between two polymer surfaces [93] (Fig. 11b).…”

“…a) Temperature distribution across LIG during RF field exposure [93]. b) LIG (black rectangle) heating upon exposure to RF fields, allowing for polymer chains to diffuse across the interface and form a weld [93]. c) Schematic of the THz focal plane imaging system [109].…”

Enhanced Graphene Sensors via Multi-Lasing Fabrication

“…Self-heated gas sensors obtained by dispersing nanomaterials with different selectivity on porous LIG surface were used for deconvolution of various gaseous components in the mixture [14] . The exploitation of LIG in the microwave, radio wave [16] and terahertz regimes [17] and in solar-tothermal [18] T progress from individual LIG devices to all-LIG integrated systems by combining wireless transmission, energy harvesting modules and stretchable sensors into a single platform [15] . Due to the coupled mechanicselectromagnetic design, the wideband dipole antenna showed deformation-independent radiation properties to be used in self-powered systems, remote monitoring of the environment, and clean energy applications [15] .…”

Site‐Specific Selective Bending of Actuators using Radio Frequency Heating

“…Our group has previously demonstrated that certain nanomaterials act as RF susceptors, such that they will heat rapidly in response to an applied field; this allows for volumetric heating in a composite with susceptor fillers, such as carbon nanotubes (CNTs), laserinduced graphene (LIG), MXenes, [24] and carbon black. [23,[25][26][27] This phenomenon has been applied to a range of manufacturing applications such as welding of polymer sheets, [28] curing of epoxy nanocomposites [23] or preceramic polymer composites, [29] and screening of CNT circuits. [25,27] We have shown that the sample does not have to be directly connected to the power source, and it can heat the carbon nanomaterials at different applicator configurations (parallel plate and fringing field).…”