Banca de DEFESA: BEATRIZ SAKAMOTO ARSUFFI

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
DISCENTE : BEATRIZ SAKAMOTO ARSUFFI
DATA : 18/04/2024
HORA: 09:00
LOCAL: Remote: https://meet.google.com/gdz-avjd-zco
TÍTULO:

MULTI-RESPONSIVE 3D/4D PRINTED NANOCELLULOSE-BASED HYDROGELS PROGRAMMABLE IN SPACE AND TIME

PÁGINAS: 118
RESUMO:

Stimuli-responsive materials are desirable for a variety of functional applications, that range from biomedical devices, sensors and actuators to adaptive surfaces and deployable structures. However, as the natural environment offers multiple stimuli at the same time, current materials often lack multi-responsiveness and display poor control over their properties over time. This work introduces an innovative multi-stimuli-responsive material platform, realized via additive manufacturing, that can be precisely programmable both in space and time. First, composite hydrogels formed by double-network matrices of poly(N-isopropylacrylamide) (PNIPAM) and sodium alginate and reinforced by a high content (15 wt%) of cellulose nanocrystals (CNC) and nanofibers (CNF) were developed and printed via Direct Ink Writing (DIW). The alignment of the reinforcing particles, induced by intense shear and extensional forces during DIW, provides composites with a highly anisotropic microstructure, key to governing the swelling/shrinking direction of printed architectures. Hence, it is possible to control the reversible shape-morphing of actuators, as well as their activity in time, as a fourth dimension (4D printing), in response to temperature. Building on the knowledge gained on these composites and aiming at multi-stimuli-responsiveness, bilayer systems including poly(acrylic acid) (PAA) hydrogel have been fabricated by multimaterial printing. The bidirectional bending performance of printed bilayers in response to multiple stimuli scenarios, such as variations of temperature, pH, and ion concentration levels is investigated. As well as their mechanical properties, swelling/shrinking behavior, and area change under time-dependent conditions. The outcomes of the characterizations demonstrate the intricate sensitivity to stimuli and programmability of the developed materials. Finally, to leverage the multi-responsiveness of this new material platform, this work incorporates concepts of materials logics, including Boolean algebra and logic gates, paving the way to logic matter.

MEMBROS DA BANCA:
Presidente - Interno ao Programa - 2352043 - SILVIA LENYRA MEIRELLES CAMPOS TITOTTO
Membro Titular - Examinador(a) Externo à Instituição - DAVID CORREA - UW
Membro Titular - Examinador(a) Externo à Instituição - DANILO BARBOSA LIARTE
Membro Suplente - Examinador(a) Interno ao Programa - 2269065 - ROMULO GONCALVES LINS
Membro Suplente - Examinador(a) Externo ao Programa - 1676364 - JULIANA MARCHI