High pressure Raman Spectroscopy, from aromatics amines to conducting polymers
| Grant number: | 15/09763-2 |
| Support type: | Scholarships abroad - Research Internship - Post-doctor |
| Effective date (Start): | December 01, 2015 |
| Effective date (End): | November 30, 2016 |
| Field of knowledge: | Physical Sciences and Mathematics - Chemistry |
| Principal Investigator: | Marcia Laudelina Arruda Temperini |
| Grantee: | Marcelo Medre Nobrega |
| Supervisor abroad: | Roberto Bini |
| Home Institution: | Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil |
| Local de pesquisa : | Università degli Studi di Firenze, Italy |
| Associated to the scholarship: | 14/15107-8 - High pressure Raman Spectroscopy, from aromatics amines to conducting polymers, BP.PD |
Abstract This study is part of the post-doctoral project entitled "High pressure Raman Spectroscopy, from Aromatics amines to Conducting Polymers", FAPESP grant 2014/15107-8, which presents as the main subjects the high pressure study and reactivity of aniline and polyaniline containing gold composites (PANI-Au). High pressure research field has emerged as a new and independent research area since the pioneering work of Bridgman and with the advent of the diamond anvil cell. High pressures in the kbar range are capable of tuning the intermolecular/interatomic distances, by introducing geometrical constraints to the system and therefore increasing its energy. The system responses to the severely change in the atomic-scale and to the accumulated energy are the rearrangements of the molecular conformation and the chemical bonds, which results in a number of phenomena. So far, high-pressure studies on aniline have reported phase transition pressure and pressure stability range of the phases; however nothing has been done concerning its high-pressure reactivity and product characterization. High-pressure study on the chemical stability of aniline could provide important information about the solid state reactivity mechanism of this particular molecular system. One of the goals of this research project is the systematic study and characterization of the aniline behavior, up to 20 GPa, and the reactivity under high pressure with electronic excitation, monitored especially through infrared spectroscopy and x-ray diffraction. Most high-pressure studies have been performed in simple aromatic systems; however, one of the most important fields in chemistry is material chemistry, more specifically, conducting polymers. Our group has been studying the polyaniline behavior under extreme conditions such as temperature and pressure. We have reported the effect of the morphology in the behavior of the doped and dedoped forms of PANI during the compression-decompression cycle up to 15 GPa, monitored through Raman and FTIR spectroscopies. This result has suggested a specific cross-linking reaction which occurs when coupling two adjacent quinoid rings, resulting in a recovered non-aromatic three-ring, likely as metastable form at ambient pressure. Associating PANI and gold nanoparticles may result in the synergism of their properties, leading to a hybrid material that can exhibit enhanced catalytic, electric and optical properties. Despite the number of studies concerning PANI and metallic nanostructures in the literature, none have reported the behavior of these materials under high pressure. In this particular open field of material science lays the second goal of this project: the study of the effect of the presence of the gold nanoparticles in PANI behavior under high pressure. We believe that this studies at the University of Florence will not only complement our experimental results that have been carried out in Brazil, but also, the expertise of Bini and his group will contribute to improve the high-pressure research field at our lab. (AU) | |