Highly Efficient, Electro-thermal Heater Based on Marangoni-Driven, Oriented Reduced Graphene Oxide/Poly(ether imide) Nanolaminates

Due to their outstanding electrical and thermal properties, graphene and related materials have been proposed as ideal candidates for the development of lightweight systems for thermoelectric applications. Recently, the nanolaminate architecture that entails alternation of continuous graphene monolayers and ultrathin polymer films has been proposed as an efficient route for the development of composites with impressive physicochemical properties. In this work, we present a novel layer-by-layer approach for the fabrication of highly ordered, flexible, heat-resistant, and electrically conductive freestanding graphene/polymer nanolaminates through alternating Marangoni-driven self-assembly of reduced graphene oxide (rGO) and poly(ether imide) (PEI) films. The microstructure, the mechanical behavior, and the electrical conductivity of the produced Marangoni rGO/PEI nanolaminates are studied as a function of rGO content (up to 5.2 vol %). These nanolaminate thin films show excellent heating properties, with fast heating responses at high temperatures to maximum temperatures at ca. 325 °C due to the Joule heating effect, at maximum rates of 444 °C/s, thus bringing forward an impressive potential of these materials for electrothermal applications. The areal power density was found to be 30 kW/m² for the 5.20% volume fraction of rGO and 325 °C temperature. The robust highly flexible heaters developed in this research hold great promise for a whole range of applications.