Printing A Heatsink—The Emergent Properties Of 3D Printable Thermally Conductive Polymer Composites

While everyday device sizes continue to shrink, the power being packed into them increases drastically, driving internal heat generation to the point of overwhelming current thermal management solutions and to the point of limiting system-level performance. Incumbent materials solutions including metals like copper and aluminum can satisfy many applications, however they are heavy and cannot be placed adjacent to electronics or in the proximity of radio frequency components due to their intrinsic electrical conductivities. Therefore, a lightweight and dielectric thermal management materials solution is desirable to support higher energy density electronics. Certain dielectric ceramics, known as phononic conductors, can effectively transport heat through atomic vibrations without electron movement. Due to the manufacturing complexities associated with these ceramics, interest in filling thermoplastic polymers with these phononic conductors has grown. Additive manufacturing paired with fine-tuned composite creation can enable the lightweight and geometrically complex thermal management solutions required for future energy dense electronics. Here we present a collection of new understandings around process-structure-property relationships that will help enable higher performing thermal parts via additive manufacturing. This work focuses on the interplay between the filament composition, the processing conditions of fused filament fabrication (FFF), and the post-processing of printed parts (annealing). The goal of this research is to enable emergent properties in FFF printed composites through material interface and interphase engineering, flow-induced self-assembly of mesostructure, and temperature-induced self-assembly of polymeric nanostructure. We demonstrate that for common electronic and radiofrequency device applications, this new class of advanced thermal management materials can be used to produce heat sinks that cool as effectively as their heavier metal counterparts currently in use in industry.