Improvisation of polylactic acid (PLA)/exfoliated graphene (GR) nanocomposite for detection of metal ions (Cu2+)

Abstract The present work attempts fabrication of thin film based metal ion sensor, where bio based thermoplastic polymer PLA is used as a matrix because of its mechanical strength and casting ease. Detection of copper ion as the representative metal ion is aimed in this work. Exfoliated graphene (GR) was used as reinforcement material to impart high conductivity in the PLA matrix due to its mechanical strength, thermal stability and electrical conductivity. A comparison of concentration detection with a commercial conductivity meter was also carried out. Dependency of current in different metal ions and different anionic environments was also studied. Various materials such as EDTA, albumin and silk nanocrystal (SNC) having bonding property with metal ions were also incorporated into the PLA/GR system in order to improve the sensitivity and selectivity towards copper ion chosen for this work. Basic characteristics like morphology, thermal stability, crystallization property and dynamic mechanical strength of the composite films were investigated before use as a sensor. I–V characteristics indicate the presence of the peak current for different cases based on the binder. Peak current is found to be increased with the concentration of copper.