Electrically assisted continuous vat photopolymerization 3D printing for fabricating high-performance ordered graphene/polymer composites

Ordered graphene/polymer composites have gained significant research interest due to their electrical conductivity, mechanical strength, and thermal stability. However, great challenges remain in achieving high-efficiency vat photopolymerization 3D printing of high-performance ordered graphene/polymer composites due to the low printing speed and the decreased ductility caused by the polymerization difficulty from the light-absorbing and shadowing of graphene nanoplatelets. Here, an electrically assisted continuous vat photopolymerization 3D printing technology using a dual-cure polymer (photo/thermal) is proposed for fabricating the high-performance ordered graphene/polymer composites. Firstly, process parameters (graphene content, printing speed, and light intensity) in the 3D printing were optimized and investigated on the composites with various graphene contents. Then, the relationship of the graphene nanoplatelets arrangement and the intensity of the electric field was established. Subsequently, multiple mechanical properties of ordered composites resulted from various graphene amounts were systematically investigated. Our results demonstrated that compared to the pure polymer, the ordered 2 wt% graphene/polymer composite has a 101% higher tensile strength (89 MPa), 200% higher total elongation (27.69%), 126% higher flexural strength (139.9 MPa and 20.6%), and 98% higher fracture strain. Besides, the electrical conductivity of the polymer composite with ordered graphene structure was 15 times higher than that of the random polymer composite. Thus, the proposed electrically assisted continuous vat photopolymerization 3D printing with photo/thermal dual-curing polymer matrix not only successfully realizes the continuous fabrication of ordered graphene/polymer composites, but also improves mechanical properties (both strength and ductility) and electrical conductivity.