Multicomponent Template EffectsPreparation of Highly Porous Polyaniline Nanorods Using Crude Lemon Juice and Its Application for Selective Detection of Catechol

This paper deals with the preparation and characterization of three different polyaniline samples, namely, PANI-HCl (synthesis in inorganic acid), PANI-Citric acid (synthesis in organic acid), and PANI-Lemon (synthesis in crude lemon juice–biological-derived acidic solution). PANI-Lemon is a low-density polymer with well-defined nanorod shape morphology (∼100 nm in diameter and ∼300–600 nm in length). Lemon juice manipulates the morphology of PANI because it has a lower pKa and the matrix molecules produce template-like effects. The distinct structure of PANI-Lemon was confirmed from microscopic and spectroscopic analysis. In the same protonating condition, the alignment of chains is the dominating factor which governs the conductivity of polyaniline. PANI-Lemon was successfully applied for the electrocatalytic detection of catechol. The selective interaction of PANI-Lemon with catechol leads to the generation of a new redox center. PANI-Lemon-modified carbon paste electrode exhibited high sensitivity (49.68 μA μM–1 cm–2), specificity, a wide linear range (from 5 μM to 100 mM), a low detection limit (2.1 μM), and less response time (2 s). On the basis of our results, we propose an eco-friendly concept "multicomponent template effects" to bring nanoscale morphological manipulation using a suitable natural extract. This concept could be equally implemented to synthetic polymers and other nanoparticles.