Development of a stretchable conductor array with embedded metal nanowires

In this paper, we presented the design, fabrication, and testing of a new type of stretchable conductor array with embedded nanowires. The conductor array could serve as the interconnect for skin-like, conformal circuits, which is one of the key components in a stretchable tactile sensor for minimally invasive surgery (MIS) devices and robots to measure the contact force, where both stretchability and conductivity are required. One example of such applications is to measure the contact force between a colonoscope and the colonic wall during colonoscopy. The proposed conductor array was fabricated by embedding several parallel silver-nanowires (AgNWs) strips (one strip is in the dimension of 3 mm wide, 360 mm long, and less than 0.01 mm thick) into the surface of a polydimethylsiloxane (PDMS) thin film (50 mm wide, 360 mm long 1 mm thick). The conductor array was then wrapped around the surface of a colonoscope for bending tests. The results from the bending tests have demonstrated that the conductor strip has a stable resistance (around 50 Ω) when the bending radius changes from 150 to 25 mm. Multitime bending tests have shown no conductivity change. Moreover, wiping tests have shown that the AgNWs/PDMS conductor array could survive external damage from its working environment. With the good repeatability and unchanged conductivity during stretching, the conductor array developed in this paper is applicable to a stretchable tactile sensor.