Adhesive Strength of Carbon Nanotubes to Stainless Steel Substrate

The adhesive strength of carbon nanotubes (CNTs) to the substrate on which they are grown is an important characteristic to know in many applications, particularly in biomedical applications where detached CNTs could pose a potential health risk. In this work, we develop a procedure for testing the adhesive strength of CNT films to a substrate, and present initial results of that procedure for CNTs grown on 316L stainless steel. Testing was conducted for CNTs grown at temperatures ranging from 700-800°C for times ranging from 3-40 minutes. The procedure involves pressing a 2x2mm square of adhesive tape onto a CNTs sample up to a standard force using an Instron tensile tester, then raising the tape back up and examining the resulting force data to obtain an adhesive strength. Trends from our initial data include, for a given growth time, an increase in adhesive strength with increasing growth temperature. We also find that, in general, adhesive strength increases with growth time for a given temperature up to 20 minutes, then levels off, though for 700°C and possibly 750°C we find an unexpected decrease in adhesive strength after 20 minutes. We propose some possible causes of this decrease, though further testing and electron microscopy will be needed to verify the existence of this phenomenon.