Production and Characterization of Electroactive Polymeric Membranes by Electrospinning

• Autor(a) principal: Rêgo, Pedro Maria Caetano Lopes de Carvalho e
• Data de Publicação: 2019
• Tipo de documento: Dissertação
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10362/91956
• topic: Electrospinning; Fibres; Membranes; P(VDF-co-TrFE); Electroactive; Pyroelectric; Domínio/Área Científica::Engenharia e Tecnologia::Engenharia dos Materiais

In the last decades the development in miniaturization of devices has become a very important topic for the future of technology. Although the miniaturization of devices has been successful in de-creasing the size of devices, the same can not be said about their energy sources. Recent work in the nanomaterials filed has started to show some progress in the towards self-powered energy sources that generate power form the environment that surrounds them. This energy can be scavenged from solar, thermal, mechanical, etc. The advances in this area shows that is possible to generate this environmental energy using nanomaterials with different architectures: nanowires, nanofibers and films. In this work nanofibrous membranes produced by electrospinning were used as nanogenerators. Electrospinning is a low-cost, easy and scalable methods to produce nanofibers. The fibres and mem-branes produced can have different morphologies, thicknesses and are lightweight, therefore being good candidates for miniaturized devices and wearables, etc. The nanofiber membranes were produced with Poly(vinylidene fluoride-co-trifluoroethylene) (P(VDF-co-TrFE)), which is a polymeric electroactive material with good piezoelectric and pyroelec-tric properties, and is commonly used has an energy generator. The energy generation is highly associ-ated with the crystalline structure of its β-phase. Three different materials (Carbon Paint, PEDOT:PSS and Aluminium), were used to create the electric contacts of this nanogenerator. The contacts where deposited by electrospinning (PEDOT.PSS), airbrush (Carbon Paint and PEDOT:PSS) and by thermal evaporation (Aluminium). DSC, XRD, FTIR, Pyroelectric Constant, Impedance spectroscopy, Tensile Strength, etc. were used to characterize the behaviour and properties of the materials and device. The electrospinning process did not show any increase in β-phase fraction and the dipoles do-mains orientation. Airbrush deposition of PEDOT:PSS was the only process that produced an electric contact capable of being used on a device. After poling, the device displayed a pyroelectric response, thus showing that the poling process improved the electroactive properties of the polymer.