Preparation and Characterization of Novel Polyaniline Nanosensor for Sensitive Detection of Formaldehyde

Nanomaterials are promising in the field of optical sensors due to their unique properties. Emeraldine base of polyaniline (Nano EB-PANI) was prepared, characterized and applied as an optical formaldehyde sensor. FTIR data confirm the formation of the EB-PANI. TEM and SEM revealed the size and shape of the nanoscale EB-PANI. XRD showed that the obtained nano EB-PANI has a partial crystalline nature. The sensing mechanism is based on the reaction of formaldehyde with Nano EB-PANI- to form a complex as described by molecular modeling HF/3-21G** level of theory. Results showed that Nano EB-PANI- detect low concentrations of formaldehyde ranging from 0.0003 to 0.9 ppm in a dose-dependent manner. The molecular modeling theory analysis showed that formaldehyde could interact with the amine of EB-PANI in, ring 3 or 4 or both together. The binding energy and dipole moment of the interaction between formaldehyde and polyaniline nanosensor were calculated by HF/3-21g** level of theory. The interaction with ring 3-NH gives a less stable product with a high dipole moment 6.978 Debye comparing with 1.678 Debye for the product of formaldehyde interaction with the terminal ring 4-NH. The development of such novel EB-PANI nanosensor can be used as, reliable and sensitive formaldehyde sensor.