High-resolution, conductive graphene/SiOC array nozzles via continuous vat photopolymerization 3D printing for electrohydrodynamic applications

Multichannel micro/nano-scale printing using arrayed nozzles offers a promising route to enhance the throughput and industrial viability. However, fabricating ultra-small array nozzles that are simultaneously high-precision, electrically conductive, and heat-resistant remains challenging. Here, we report a continuous vat photopolymerization (VPP) 3D printing strategy that exploits two synergistic effects: (i) a reduced-viscosity graphene/polysiloxane slurry achieved via a modified interfacial bonding, and (ii) its pronounced pyrolysis shrinkage. Specifically, sulfuric acid modification introduces –OH groups onto graphene, enabling Si–O–C bonding with Si–OH from the photosensitive polysiloxane slurry. Meanwhile, self-condensation of Si–OH and photopolymerization of C=C bonds form a dense carbon–oxygen–silica network, markedly enhancing slurry stability and uniformity. Furthermore, by harnessing thermal shrinkage together with the oxygen-inhibition-induced “dead zone” during continuous curing, we obtain ultra-small nozzle apertures with smooth inner walls using conventional printing equipment, effectively eliminating the staircase effect. The resulting array nozzles feature a minimum inner radius of 27.79 μm and inter-nozzle inner-radius variation of only 1.15 μm. When applied to multi-material EHD printing, the nozzles produce highly uniform deposits, with the difference in coefficient of variation of linewidth among nozzles reaching as low as 0.34%. This work provides an efficient route to fabricate high-precision, conductive, and thermally stable array nozzles for scalable micro/nano additive manufacturing.