Fig. 3.
Multiscale Print Process. a The microstructured multimaterial filament is fed quickly through a short hot end. Precision of the print can be enhanced by using hot end and filaments of smaller diameters. b Filament surface heating (FSH) generates a surface-heated effect with the filament surface temperature rising beyond its critical fusing temperature (Tcrit) while maintaining the temperature of the inner encapsulating polymer at a temperature below its glass transition (Tg). Microscale features within the ink can be precisely arranged for varying functionalities. c, d Cross-sectional optical micrographs showcasing a hierarchical assembly of millimeter-scale fused lines containing interfacial microstructures of different material classes. These assembly can be further stacked and shaped into three-dimensional centimeter-scale objects like e a star and a f pyramid which are printed from the light-emitting and light-detecting filaments, respectively, via FSH. Speed-temperature plots for the printing of g PC-cladded light-detecting and h COC-clad/PC-core light-emitting filaments