Banca de DEFESA: JAQUELINE FALCHI DA ROCHA

Uma banca de DEFESA de DOUTORADO foi cadastrada pelo programa.
STUDENT : JAQUELINE FALCHI DA ROCHA
DATE: 19/12/2023
TIME: 14:00
LOCAL: Remoto
TITLE:

FABRICATION OF FLEXIBLE ELECTROCHEMICAL DEVICES BASED ON PYROLYZED PAPER MODIFIED WITH POLYDOPAMINE

PAGES: 10
BIG AREA: Ciências Exatas e da Terra
AREA: Química
SUBÁREA: Química Analítica
SPECIALTY: Eletroanalítica
SUMMARY:

Paper-based analytical devices are a good alternative among sensors used in the pharmaceutical, food, and agricultural industries as they are based on a simple, low-cost, and biodegradable material. Among the device production techniques, paper pyrolysis is the one that has gained prominence as it makes the material itself conductive, yet fragile and hydrophobic. Therefore, in this work, the pyrolysis of paper will be explored for the development of electrochemical devices, in addition to being flexible by incorporating polymers into the pyrolyzed material, taking advantage of the porosity of the cellulose substrate. After pyrolysis, it is interesting that it is functionalized, so in this sense, the substrate will be modified with polydopamine. After the functionalization process, it was observed that the presence of the polydopamine film introduces chemical functionalities rich in oxygen (O-C=O) and nitrogen (R-NH₂, R₂-NH, =N-R) which decrease the contact angle from 114° to 0°. In a second pyrolysis step, the heat treatment of polydopamine at different temperatures brings to the paper changes in the chemical composition of the surface and the ratios of these compounds can be controlled by temperatures. Such chemical modifications were monitored using SEM, XPS, confocal microscopy, Raman, contact angle, TEM, cyclic voltammetry and electrical measurements. Functionalization brings superhydrophilicity to the paper, the thermal treatment of polydopamine varies the chemical composition of the coating, thus altering wettability (0 to 89°), improving resistivity (75 to 62 mΩ cm^-1) and helping to reduce values ∆Ep (240 mV to 68 mV) when the temperature reaches 1000°C. Furthermore, when preparing gold nanoparticles on this substrate, the different temperatures applied in the thermal treatment of polydopamine make it possible to control the concentration, distribution, and size of the nanoparticles along the fibers, including the inner regions of the paper. Therefore, handling these configurations becomes highly beneficial for advances in the creation of sensors and biosensors, increasing sensitivity and enabling future functionalization processes for the immobilization of biological recognition agents.

COMMITTEE MEMBERS:
Presidente - Interno ao Programa - 050.966.059-22 - MURILO SANTHIAGO - CNPEM
Membro Titular - Examinador(a) Interno ao Programa - 1671688 - ANDRE SARTO POLO
Membro Titular - Examinador(a) Externo à Instituição - CHRISTIANE DE ARRUDA RODRIGUES - UNIFESP
Membro Titular - Examinador(a) Externo à Instituição - JACQUELINE ARGUELLO DA SILVA - UFRGS
Membro Titular - Examinador(a) Externo à Instituição - LUIZ HENRIQUE DALL''ANTONIA - UEL
Membro Suplente - Examinador(a) Interno ao Programa - 1544341 - WENDEL ANDRADE ALVES
Membro Suplente - Examinador(a) Interno ao Programa - 007.041.553-62 - RENATO SOUSA LIMA - UNICAMP
Membro Suplente - Examinador(a) Externo à Instituição - CLAUDIO RADTKE - UFRGS
Membro Suplente - Examinador(a) Externo à Instituição - JOAO BATISTA SOUZA JUNIOR - LNNANO