Carbon nanotube (CNT) forests are arrays of free-standing CNTs, as seen in Fig. 1a. The goal of this project was to deposit 1,5-diaminonaphthalene (DAN) evenly on each CNT. The motivation is that CNTs cannot effectively participate in chemical reactions by themselves. However, DAN can bind to the CNT surface in such a way that it can participate in chemical reactions while staying on the CNT side wall1. If DAN could be coated evenly on the CNTs throughout the forest, it could make a very sensitive biological sensor. A sensor is only as good as the number of detection sites, and the large surface area in a CNT forest provides ample opportunity for many detection sites. Initially, we tried immersing CNT forests (of about 50 μm height) in solutions of DAN, but it was found that the CNT forest deformed so much that there was little CNT surface to which DAN could bind.
Pound, Ben, "Carbon Nanotube Sensors and Field Emitters" (2014). Physics Capstone Projects. Paper 16.