Banca de QUALIFICAÇÃO: MAXWELL OGOCHUKWU OJUKWU

Uma banca de QUALIFICAÇÃO de DOUTORADO foi cadastrada pelo programa.
DISCENTE: MAXWELL OGOCHUKWU OJUKWU
DATA: 04/08/2026
HORA: 15:00
LOCAL: Anfiteatro do DFI
TÍTULO:

Development of Functionalized Cellulose Acetate-Conductive Polymer Composite Coatings for Advanced Fabry-Perot Optical Fiber Chemical Sensing Applications

PALAVRAS-CHAVES:

Fabry-Perot optical fiber sensor, Cellulose acetate-polyaniline composite, Optical fiber sensing, pH sensor, Functional coatings.

PÁGINAS: 70
GRANDE ÁREA: Ciências Exatas e da Terra
ÁREA: Química
SUBÁREA: Química Analítica
ESPECIALIDADE: Instrumentação Analítica
RESUMO:

The increasing demand for compact, highly sensitive, and sustainable sensing technologies has driven the rapid development of functionalized optical fibre sensors for chemical and biological applications. Of these, Fabry-Perot interferometric (FPI) optical fiber sensors offer high sensitivity, compact size, immunity to electromagnetic interference, and real-time sensing capability. However, their performance is highly dependent on the properties of the functional coating. This study investigates the development of cellulose acetate-polyaniline (CA-PANI) composite coatings as functional materials for Fabry-Perot optical fiber pH sensing. Cellulose acetate was dissolved in acetone, while chemically synthesized polyaniline particles were ultrasonically dispersed in chloroform before gradual mixing to produce a homogeneous composite suspension. The composite composition was optimized by varying the polyaniline content from 10 to 40 wt%, with the optimum formulation consisting of 20 wt% polyaniline and 80 wt% cellulose acetate. The optimized composite was deposited onto Fabry-Perot optical fiber tips using a controlled drop-casting technique, and the coating thickness was optimized through successive deposition cycles. Scanning electron microscopy confirmed the formation of continuous, well-adhered coatings with uniform polyaniline dispersion. Optical characterization revealed well-defined interference fringes within the 1500–1600 nm wavelength range, confirming successful Fabry-Perot cavity formation. The functionalized sensor exhibited measurable spectral responses to Britton-Robinson buffer (BR 0.1 mol/L) solutions over the pH range of 2.0 to 6.0, indicating the sensitivity of the CA-PANI coating to hydrogen ion concentration. These findings establish the CA-PANI composite as a promising functional material for Fabry-Perot optical fiber pH sensing and provide a foundation for future optimization toward advanced chemical and biosensing applications.

 

MEMBROS DA BANCA:
Externo ao Programa - MIRIANY AVELINO MOREIRA FERNANDEZ - DQI/ICN (Suplente)
Interno - JULIO CESAR UGUCIONI (Membro)
Externo ao Programa - JONAS HENRIQUE OSORIO - DFI/ICN (Membro)
Externo ao Programa - FLAVIO AUGUSTO DE MELO MARQUES - DFI/ICN (Membro)
Presidente - FABIANA DA SILVA FELIX (Membro)
Interno - ALEXANDRE ALBERTO CHAVES COTTA (Suplente)