Temperature Measurement of Carbon Nanotubes Using Infrared Thermography

Multiwalled carbon nanotubes (MWNTs) have a very high absorbance in the near-infrared (NIR) region of the electromagnetic spectrum. It is demonstrated that the temperature of MWNTs, measured using infrared thermography during NIR laser irradiation, is much higher than that of other carbonaceous materials such as graphite controls. Since most biological materials have a low absorbance in the same region, carbon nanotubes could be used for selective photothermal hyperthermia of biological or nonbiological systems. This study was performed to prove the concept of direct measurement of the temperature distribution of carbon nanotubes when stimulated with laser irradiation. The maximum temperature increase of MWNTs measured with a high-sensitivity infrared camera, continuously irradiated with four 2.5-mW/650-nm lasers, was 7 °C vs a graphite control, while irradiation with a 390-mW/1064-nm laser yielded maximum temperature increases of more than 100 °C above the graphite control. The use of infrared thermography has allowed for specific data on laser-mediated heating kinetics of MWNTs to be presented here for the first time to our knowledge. These results could prove very useful in the design of selective photothermal processes of selectively destroying biological systems of interest.