| dc.description.abstract | In this report, we investigate laser-induced graphite (LIG) structures formed in polymeric substrates in order to quantify LIG heating response to radio frequency (RF) fields. Graphitic structures were produced from various polymeric substrates via laser irradiation of the polymer surface. We find that RF responsive, graphitic structures may be produced from polyimide (PI), polyether imide (PEI), polyether sulfone (PESU), polyether ether ketone (PEEK), and polycarbonate (PC) using a conventional laser cutting machine. The graphitic structures are also conductive in addition to being RF responsive. Exposure of LIG to RF fields resulted in the rapid heating of LIG with heating rates up to 126 °C/s. 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. This technique uses RF fields to induce localized heating in contrast to uniform heating from external sources such as ovens or furnaces. Finally, we aim to determine how LIGpolymer composites may function in an industrial setting, with particular application to additive manufacturing and functional coatings.
One novel application of these findings is the potential use of LIG-polymer heating elements on thermoplastic filaments for welding 3D-printed filament traces together and improving the isotropic strength of 3Dprinted structures. First, we review the necessary background information on LIG formation, thermoplastic joining, and nanomaterial heating in response to electromagnetic fields. We then describe the laser etching procedure used to produce graphitic structures from neat polymer substrates. The method and experimental setup required to generate RF fields and subsequent RF field heating are also addressed. The proposed work would enable entirely new techniques for polymer processing, where the RF responsive filler is generated in situ. | |
