BCMaterials Fortnightly Seminar #82 Alberto Maceiras - Nelson Castro

ALBERTO MACEIRAS

(BCMATERIALS)

Optimized Magnetodielectric Coupling on High-Temperature Polymer-Based Nanocomposites

CoFe₂O₄ (CFO) ferrite nanoparticles with an average size of 15 nm were synthesized by a hydrothermal method and used to develop magnetodielectric (MD) composites with the piezoelectric copolyimide 2CN/0CN as polymer matrix. It is shown that the dielectric constant, dielectric loss, and saturation magnetization values of the composites increase with the increasing CFO content, being 4.4, 0.01, and 12 emu.g-1, respectively, for the sample with 20 weight percentage (wt.%) of ferrite. Additionally the large MD effect response (MDE(%)=10.15) and magnetodielectric coefficient (γ)=5.8x10^-2) allows a new physical insight on the magneto-mechano-electrical interaction between magnetostrictive CFO and the polymer matrix. Such high MD response, the highest reported for polymer-based composite materials, can support innovative applications in the areas of sensors, actuators, and filters, among others

NELSON CASTRO

(BCMATERIALS)

Design, construction and validation of a new generation of bioreactors for tissue engineering applications

This doctoral project aims to, design, fabricate and validate a new generation of portable bioreactors for cell culture stimulation, in order to improve tissue engineering strategies, exploiting responsive materials microenvironments resembling some of the most common physical stimuli within the human body. Some stimuli can be produced by polymer-based scaffolds such as magnetoelectric, which can work as mechanical and electrical actuators. In this particular case, applying an alternated magnetic field to these transducers, they will vibrate and that mechanical stress will be applied directly in the cell culture process. Further, the mechanical variations can originate a varying electrical signal in a piezoelectric material. Literature in this field claims a cell proliferation enhancement up to 25% with mechanical and electrical stimulation. This project will develop two types of bioreactors: one of them with electromechanical stimuli (mechanical and electric stimuli) and another with magneto-mechanical and magnetoelectric stimuli. Both stimuli will be highly controlled by an electronic system. Thus, this project encompasses several fields of engineering such as device engineering, design, mechanics and electronics, having also into account proper material selection and the final biomedical application.