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Smart 3D printed structural components with self-monitoring ability show potential applications in some extreme environments, such as deep-water and space. Fused deposition modeling (FDM) provides a feasible solution; however, it is still a big challenge to print structural components with high bending and stretching mechanical properties because of the weak interlayer bonding and the pores. Here, a low-cost and facile fabrication strategy of smart components combining FDM with laser-scribing technology is reported. A thin laser-induced graphene (LIG) layer (∼50 μm) can serve as the active materials of sensors, which can be obtained on the printed polyetheretherketone (PEEK) components. Accordingly, the PEEK−LIG smart components (PEEK−LIG SCs) can self-monitor the working process and the deformations (bidirectional bending and stretching) in real time with high sensitivity. For instance, the gauge factors of PEEK−LIG SCs for bending outward and stretching are up to 155.36 and 212.35 (2−5% strain), respectively. Besides, the PEEK−LIG SCs possess good reliability (>1000 cycles), fast response time (60 ms), and recovery time (247 ms). We further show the excellent performance of the PEEK−LIG smart gear in monitoring the rotation and the abrasion, indicating the wide potential applications of this strategy.

Fused deposition modeling possesses great advantages in fabricating high performance composites with controllable structural designs. As such, it has attracted attention from medical, automatic, and aerospace fields. In this paper, the influence of short carbon fibers (SCFs) and the orthogonal building orientation on the flexural properties of printed polyether ether ketone (PEEK) composites are systematically studied. The results show that the addition of SCFs raises the uniform nucleation process of PEEK during 3D printing, decreases the layer-to-layer bonding strength, and greatly changes the fracture mode. The flexural strength of vertically printed PEEK and its CF-reinforced composites show strengths that are as high as molded composites. X-ray micro-computed tomography reveals the microstructure of the printed composites and the transformation of pores during bending tests, which provides evidence for the good mechanical properties of the vertically printed composites. The effect of multi-scale factors on the mechanical properties of the composites, such as crystallization in different positions, layer-by-layer bonding, and porosity, provide a successful interpretation of their fracture modes. This work provides a promising and cost-effective method to fabricate 3D printed composites with tailored, orientation-dependent properties.

A new strategy for efficient RTP from CDs by engineering the conjugation degree and controlling the hydrogen-bonding structure is proposed.

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