Publications

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Journal Article
Soares, P. I. P., C. A. T. Laia, A. Carvalho, L. C. J. Pereira, J. T. Coutinho, I. M. M. Ferreira, C. M. M. Novo, and J. P. Borges, "Iron oxide nanoparticles stabilized with a bilayer of oleic acid for magnetic hyperthermia and MRI applications", Appl Surf Sci, vol. 383, pp. 240-247, 2016. AbstractDOI

Iron oxide nanoparticles (Fe3O4, IONPs) are promising candidates for several biomedical applications such as magnetic hyperthermia and as contrast agents for magnetic resonance imaging (MRI). However, their colloidal stability in physiological conditions hinders their application requiring the use of biocompatible surfactant agents. The present investigation focuses on obtaining highly stable IONPs, stabilized by the presence of an oleic acid bilayer. Critical aspects such as oleic acid concentration and pH were optimized to ensure maximum stability. NPs composed of an iron oxide core with an average diameter of 9 nm measured using transmission electron microscopy (TEM) form agglomerates with an hydrodynamic diameter of around 170 nm when dispersed in water in the presence of an oleic acid bilayer, remaining stable (zeta potential of −120 mV). Magnetic hyperthermia and the relaxivities measurements show high efficiency at neutral pH which enables their use for both magnetic hyperthermia and MRI.

Esperança Garcia, D. M., A. S. Taborda Martins Pereira, A. C. Almeida, U. Santana Roma, A. Ben Aissa Soler, P. D. Lacharmoise, I. M. M. das Ferreira, and C. C. D. Simao, "Large-Area Paper Batteries with Ag and Zn/Ag Screen-Printed Electrodes", ACS Omega, vol. 4, pp. 16781−16788, 2019. acsomega.9b01545.pdf
Mendes, D., D. Sousa, A. C. Cerdeira, L. C. J. Pereira, A. Marques, J. Murta-Pina, A. Pronto, and I. Ferreira, "Low-cost and high-performance 3D printed YBCO superconductors", Ceramics International, vol. 47, pp. 381-387, 2021.
Sousa, D. M., W. Chiappim, J. P. Leitão, J. C. Lima, and I. Ferreira, "Microwave synthesis of silver sulfide and silver nanoparticles: light and time influence", ACS omega, vol. 5, pp. 12877-12881, 2020.
Picado, A., S. M. Paixão, L. Moita, L. Silva, M. S. Diniz, J. Lourenço, I. Peres, L. Castro, J. B. Correia, J. Pereira, I. Ferreira, A. P. A. Matos, P. Barquinha, and E. Mendonça, "A multi-integrated approach on toxicity effects of engineered TiO2 nanoparticles", Front. Env. Sci. Eng., vol. 9, issue 5, pp. 793–803, 2015. AbstractDOI

The new properties of engineered nanoparticles drive the need for new knowledge on the safety, fate, behavior and biologic effects of these particles on organisms and ecosystems. Titanium dioxide nanoparticles have been used extensively for a wide range of applications, e.g, self-cleaning surface coatings, solar cells, water treatment agents, topical sunscreens. Within this scenario increased environmental exposure can be expected but data on the ecotoxicological evaluation of nanoparticles are still scarce. The main purpose of this work was the evaluation of effects of TiO2 nanoparticles in several organisms, covering different trophic levels, using a battery of aquatic assays. Using fish as a vertebrate model organism tissue histological and ultrastructural observations and the stress enzyme activity were also studied. TiO2 nanoparticles (Aeroxide® P25), two phase composition of anatase (65%) and rutile (35%) with an average particle size value of 27.6±11 nm were used. Results on the EC50 for the tested aquatic organisms showed toxicity for the bacteria, the algae and the crustacean, being the algae the most sensitive tested organism. The aquatic plant Lemna minor showed no effect on growth. The fish Carassius auratus showed no effect on a 21 day survival test, though at a biochemical level the cytosolic Glutathione-S-Transferase total activity, in intestines, showed a general significant decrease (p<0.05) after 14 days of exposure for all tested concentrations. The presence of TiO2 nanoparticles aggregates were observed in the intestine lumen but their internalization by intestine cells could not be confirmed.

Loureiro, J., J. R. Santos, A. Nogueira, F. Wyczisk, L. Divay, S. Reparaz, F. Alzina, C. M. S. Torres, J. Cuffe, F. Montemor, R. Martins, and I. Ferreira, "Nanostructured p-type Cr/V2O5 thin films with boosted thermoelectric properties", J. Mater. Chem. A, vol. 2, issue 18, pp. 6456-6462, 2014. AbstractDOI

The urgent need for non-toxic and abundant thermoelectric materials has become a significant motivation to improve the figures of merit of metal oxides in order to remove the barrier towards their widespread use for thermoelectric applications. Here we show the influence of a Cr layer in boosting the thermoelectric properties of vanadium pentoxide (V2O5) thin films, deposited by thermal evaporation and annealed at 500 °C. The Cr to V2O5 thickness ratio controls the morphological and thermoelectric properties of the thin films produced. The optimized Seebeck coefficient and power factor values at room temperature are +50 μV K−1 and 7.9 × 10−4 W m−1 K−2, respectively. The nanograin structure of the films is responsible for an improvement in the electrical conductivity up to 3 × 105 (Ω m)−1 with a typical thermal conductivity of 1.5 W m−1 K−1. These results combine to yield promising p-type thermoeletric CrV2O5 thin films with a ZT of 0.16 at room temperature.

Bianchi, C., A. C. Marques, R. C. da Silva, T. Calmeiro, and I. Ferreira, "Near infrared photothermoelectric effect in transparent AZO/ITO/Ag/ITO thin films", Scientific reports, vol. 11, pp. 1-11, 2021.
Faria, P., P. Duarte, D. Barbosa, and I. Ferreira, "New composite of natural hydraulic lime mortar with graphene oxide", Constr Build Mater, vol. 156, pp. 1150-1157, 2017. AbstractDOI

Recent studies show the incorporation of graphene oxide (GO) in cement composites. But these composites are frequently incompatible with original materials for building rehabilitation. To overcome this limitation, natural hydraulic lime mortars were used as matrix, and the influence of GO percentage and type of mixing was investigated. The influence on the microstructure, mechanical and physical properties was assessed. The best results were obtained with dispersed GO at concentrations of 0.05% and 0.1%. A slight improvement of mechanical and physical characteristics was achieved. This could lead to new mortars with improved properties that can be used for building rehabilitation.

Echeverria, C., P. Soares, A. Robalo, L. Pereira, C. M. M. Novo, I. Ferreira, and J. P. Borges, "One-pot synthesis of dual-stimuli responsive hybrid PNIPAAm-chitosan microgels", Mater. Des, vol. 86, pp. 745-751, 2015. AbstractDOI

The incorporation of magnetic nanoparticles into poly(N-isopropylacrylamide) (PNIPAAm) and chitosan microgels gives rise to hybrid systems that combine the microgels swelling capacity with the interesting features presented in magnetic nanoparticles. The presence of chitosan that act as surfactant for magnetic nanoparticles provides a simplistic approach which allows the encapsulation of magnetic nanoparticles without any previous surface modification. Spherical and highly monodisperse microgels with diameters in the range of 200 to 500 nm were obtained. The encapsulation of magnetic nanoparticles in the polymer matrix was confirmed by high resolution Scanning Electron Microscopy in transmission mode. Volume phase transition of the microgels was accessed by Dynamic Light Scattering measurements. It was observed that the thermosensitivity of the PNIPAM microgels still persists in the hybrid microgels; however, the swelling ability is compromised in the microgels with highest chitosan content. The heating performance of the hybrid magnetic microgels, when submitted to an alternating magnetic field, was also evaluated demonstrating the potential of these systems for hyperthermia treatments.

Figueira, J., J. Loureiro, J. Marques, C. Bianchi, P. Duarte, M. Ruoho, I. Tittonen, and I. Ferreira, "Optimization of Cuprous Oxides Thin Films to be used as Thermoelectric Touch Detectors", ACS Appl Mater Interfaces, vol. 9, issue 7, pp. 6520-6529, 2017. AbstractDOI

The electronic and optical properties of p-type copper oxides (CO) strongly depend on the production technique as it influences the obtained phases: cuprous oxide (Cu2O) or cupric oxide (CuO), the most common ones. Cu films deposited by thermal evaporation have been annealed in air atmosphere, with temperature between 225 and 375 °C and time between 1 and 4 h. The resultant CO films have been studied to understand the influence of processing parameters in the thermoelectric, electrical, optical, morphological, and structural properties. Films with a Cu2O single phase are formed when annealing at 225 °C, while CuO single phase films can be obtained at 375 °C. In between, both phases are obtained in proportions that depend on the film thickness and annealing time. The positive sign of the Seebeck coefficient (S), measured at room temperature (RT), confirms the p-type behavior of both oxides, showing values up to 1.2 mV·°C–1and conductivity up to 2.9 (Ω·m)−1. A simple detector using Cu2O have been fabricated and tested with fast finger touch events