Selective Laser Sintering for Electrically Conductive Poly(dimethylsiloxane) Composites with Self-Healing Lattice Structures
Xue Li, Hao Ouyang, Shaojie Sun, Jinzhi Wang, Guoxia Fei, Hesheng Xia
Abstract
Developing flexible elastomer composites for sensors and effective fabrication methods is of great significance. Single-walled carbon nanotubes (SWCNTs)-wrapped poly(dimethylsiloxane) covalent adaptable networks (PDMS-CANs) composite powders were prepared through a liquid-phase deposition and adsorption process and used for selective laser sintering (SLS) three-dimensional (3D) printing. The electrically conductive PDMS composite parts with self-healing lattice structures were printed. Ingeniously utilizing the quasi-static processing characteristic of SLS printing, the conductive segregated SWCNT networks are in situ formed in PDMS-CANs during the printing process, showing an ultralow percolation threshold of 0.007 wt %. Due to the photothermal and electrothermal effects of SWCNTs, the composites possess multifunctions including crack diagnosis and self-healing triggered by heat, electricity, or light. To demonstrate the potential application, the SLS-printed SWCNTs@PDMS-CANs strain sensors with various lattice structures were designed and SLS-printed. Their strain sensitivity is compared and analyzed by finite element modeling. The results show that the TPMS Schwartz structure possesses the highest sensitivity due to the concentrated localized strain.