Study of polyaniline protonation and deprotonation process as sensing membrane of pH EGFET sensors

• Grant number: 14/12440-8
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2014
• End date: July 31, 2015
• Field of knowledge: Engineering - Electrical Engineering
• Principal Investigator: Marcelo Mulato
• Grantee: José Renato Alcarás
• Host Institution: Faculdade de Filosofia, Ciências e Letras de Ribeirão Preto (FFCLRP). Universidade de São Paulo (USP). Ribeirão Preto , SP, Brazil

Abstract

In this project, we intend to study Extended Gate Field-Effect Transistor (EGFET) pH sensors in order to improve them to future applications. Such study will be made mostly about the interference of an applied non-zero electrical potential from a reference electrode in an acid buffer solution and its consequence in the properties and structure of electrodeposited polyaniline films as sensing membranes of EGFET sensors. It will be studied the influence of distinct potential values on the change of the film's sensitivity (electric response according to pH) and the polymer structure using optical techniques.Once studied the effects of the film protonation, we intend to study the film durability by performing consecutive measurements and studying the intensity of these measurements in its sensitivities. Also, we intend to study methods in order to reverse the protonation by electrochemical and physical techniques. By the end, we want to understand the influence of potentials in the polymer's structure in pH measurements to obtain films with different sensitivities.Previous results already indicate PANI's protonation, reducing its sensitivity, for a specific non-zero referential potential. We were able of reversing the protonation for this case, motivating the study for different potentials.