Experimental data and modeling of electrical conductivity for polymer carbon nanotubes nanobiosensor during degradation in neutral phosphate-buffered saline (PBS)

Publication date: February 2020Source: Materials Science and Engineering: B, Volume 252Author(s): Yasser Zare, Kyong Yop RheeAbstractThis paper studies the conductivity of poly (lactic acid) (PLA)/poly (ethylene oxide) (PEO)/carbon nanotubes (CNT) nanocomposites during degradation in neutral phosphate-buffered saline (PBS) solution by experimental and modeling results. PLA/PEO/CNT nanocomposites are prepared and the conductivity of samples is measured before and during degradation. This system can be applied as a degradation nanobiosensor, because the variation of conductivity expresses the extent of degradation. A simple model is developed to predict the variation of conductivity during hydrolytic degradation. The degradation of polymers improves the effectiveness of CNT networks in the samples growing the conductivity. The proper agreement between experimental and theoretical results approves the validity of the developed model. A longer degradation time destroys more polymer chains shortening the tunneling space between CNT. The percolation threshold increases during degradation, due to the degradation of interphase zones between polymer and CNT. The calculations demonstrate that the fraction of networked CNT decreases during degradation, because PBS solution attacks the CNT networks. These reasonable predictions validate the developed equations representing the variations of conductivity, tunneling distance, percolation threshold and the fraction of networked CNT in the s...
Source: Materials Science and Engineering: B - Category: Materials Science Source Type: research