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Research Project
Development of interactive books through smart and functional materials
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Publications
Surface wettability modification of poly(vinylidene fluoride) and copolymer films and membranes by plasma treatment
Publication . Correia, Daniela M.; Nunes-Pereira, João; Alikin, Denis; Kholkin; Carabineiro, S.A.C.; Rebouta, Luis; Rodrigues, Marco S.; Vaz, F.; Costa, C. M.; Lanceros-Mendez, Senentxu
This manuscript reports on the modification of the surface wettability of poly (vinylidene fluoride) (PVDF) and PVDF copolymer films and membranes by plasma treatments at different conditions, under oxygen and argon atmospheres. It is shown that a more pronounced decrease of the contact angle after O2 plasma treatments is obtained, with a decrease of ∼20-30° for PVDF and its copolymers films, leading also to superhydrophilic membranes. This effect is related to a defluorination process, followed by the incorporation of oxygen atoms onto the surface of membranes that occurs during the surface modification. The influence of plasma treatments on surface morphology and topography was studied by atomic force microscopy, showing a decrease in the mean surface roughness with the plasma treatments, being more noticeable for Ar treatments. Finally, it is also shown that plasma treatments under Ar and O2 did not induce modifications in the physicochemical and thermal properties of PVDF and PVDF copolymers. The chemical reaction mechanism after plasma treatment is proposed for the different copolymers.
Evaluation of the Physicochemical Properties and Active Response of Piezoelectric Poly(vinylidene fluoride-co-trifluoroethylene) as a Function of Its Microstructure
Publication . Gonçalves, R.; Cardoso, V. F.; Pereira, Nelson; Oliveira, Juliana; Nunes-Pereira, João; Costa, C. M.; Lanceros-Mendez, Senentxu
Poly(vinylidene fluoride-trifluoroethylene), P(VDF-TrFE), microstructures have been produced using different solvents, including green ones, by different techniques, such as solvent casting, screen-printing, replica molding, electrospray, and electrospinning. The obtained microstructures span from simple porous and dense films to spheres, fibers, and patterned three-dimensional architectures, with no significant variation in their physicochemical and electrical properties. The simplicity, low cost, and reproducibility of the processing techniques allied to their versatility to adapt to other materials to produce controlled and tailored microstructures with specific properties demonstrate their potential in a wide range of technological applications, including biomedical, energy storage, sensors and actuators, and filtration.
Piezoelectric Energy Production
Publication . Nunes-Pereira, João; Costa, Pedro; Lanceros-Mendez, Senentxu
The concept of piezoelectric energy production is based on energy-harvesting devices using generation materials such as single crystals, ceramics, polymers, and composites. These production systems can harvest wasted environmental energy and convert it essentially into electrical energy. There are different nano- and microscale power harvesters which are increasingly useful for powering mobile electronics and low-power devices, even in hardly accessible areas. Despite many efforts in the development of new materials, the most widely used materials in device applications remain the ceramics of the lead zirconate titanate family, since they still present the higher output performances in the range of milliwatts of generated power.
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Funding agency
Fundação para a Ciência e a Tecnologia
Funding programme
9471 - RIDTI
Funding Award Number
PTDC/EEI-SII/5582/2014