Biodegradation of Carbon Nanotube/Polymer Nanocomposites using a Monoculture

The biodegradation rates of carbon nanotube (CNT)/ polymer nanocomposites (PNCs) containing poly-e-caprolactone (PCL) were investigated using Pseudomonas aeruginosa, a microorganism commonly found in the environment. CNT/PCL nanocomposite mass loss profiles revealed that the rate of PCL matrix biodegradation decreased systematically as the CNT loading increased from 0.1 to 10% w/w. Addition of even a low CNT loading (<1% w/w) caused the CNT/PCL biodegradation rate constant to decrease by more than 50%. Similar trends in biodegradation rate were observed for both pristine and oxidized multiwall CNTs embedded in PCL. During PCL matrix biodegradation, CNT accumulation was observed at the surface of CNT/PCL nanocomposites and single particle inductively coupled-mass spectrometry experiments revealed no measurable CNT release to the culture fluid. Experimental data indicated that biodegradation proceeded as a result of biofilm formation on the CNT/PCL nanocomposites and decreased as a function of CNT loading d...