Effective reinforcement of electrical conductivity and strength of carbon nanotube fibers by silver-paste-liquid infiltration processing.

A carbon-nanotube (CNT)/silver/polymer composite fiber was fabricated using carbon nanotube fiber (CNTF) to infiltrate silver-paste liquid for effective reinforcement of electrical conductivity and strength of the CNT fibers. The as-obtained composite fiber is still flexible with a content of 43 wt% CNTs. Scanning electronic microscopy (SEM) observation shows that the silver-paste layer covering on the surface of the CNTF and polymer infiltrated into the CNTFs. The electrical conductivity and strength of the achieved composite fiber were effectively improved. Mechanical measurement of the composite fiber gave a strength of 940 MPa, 2.7 times that of a reference CNTF. The electrical conductivity of the composite fiber is 5.0 × 10(5) S m(-1), 2.6 times that of the referenced CNTF. Additionally, through control of the fabrication process, a coaxial fiber comprising a silver-paste "tube" and pure CNT fiber can be achieved. This route for making composite fibers is easy and controllable, apt for development of high-performance fibers.