title: Development of polymer wicks for the fabrication of bio-medical sensors.
abstract: Polymer based wicking structures were fabricated by sintering powders of polycarbonate (PC), ultra-high molecular weight polyethylene and polyamide 12, aiming at selecting a suitable material for an innovative electroencephalography (EEG) bio-electrode. Preliminary experiments showed that PC based wicks displayed the best mechanical properties, therefore more detailed studies were carried out with PC to evaluate the influence of powder granulometry and processing parameters (pressure, temperature and time) on the mechanical properties, porosity, mean pore radius and permeability of the wicks. It was concluded that the mechanical properties are significantly enhanced by increasing the processing time and pressure, although at the expense of a significant decrease of porosity and mean pore diameter (and thus permeability), particularly for the highest applied pressures (74kPa). However, a good compromise between porosity/permeability and mechanical properties could be obtained by sintering PC powders of particle sizes below 500μm at 165°C for 5min, upon an applied pressure of 56kPa. Moreover, PC proved to be chemically stable in contact with an EEG common used disinfectant. Thus, wicking structures with appropriate properties for the fabrication of reusable bio-electrodes could be fabricated from the sintering of PC powders.
authors: Institute for Polymers and Composites/I3N, University of Minho, Campus of Azurém, 4800-058 Guimarães, Portugal; Universidade do Porto, Faculdade de Engenharia, Rua Roberto Frias, s/n, 4200-465 Porto, Portugal.
authors: Ana C
authors: AC
authors: Martins
authors: Universidade do Porto, Faculdade de Engenharia, Rua Roberto Frias, s/n, 4200-465 Porto, Portugal.
authors: André
authors: A
authors: Moreira
authors: Institute for Polymers and Composites/I3N, University of Minho, Campus of Azurém, 4800-058 Guimarães, Portugal.
authors: Ana V
authors: AV
authors: Machado
authors: Centro de Física, Universidade do Minho, 4710-057 Braga, Portugal.
authors: Filipe
authors: F
authors: Vaz
authors: Universidade do Porto, Faculdade de Engenharia, Rua Roberto Frias, s/n, 4200-465 Porto, Portugal; SEG-CEMUC, Department of Mechanical Engineering, University of Coimbra, Coimbra, Portugal. Electronic address: cfonseca@fe.up.pt.
authors: Carlos
authors: C
authors: Fonseca
authors: Institute for Polymers and Composites/I3N, University of Minho, Campus of Azurém, 4800-058 Guimarães, Portugal.
authors: João M
authors: JM
authors: Nóbrega
mesh_terms: D015374:Biosensing Techniques; D004566:Electrodes; D008855:Microscopy, Electron, Scanning; D011108:Polymers / Q000737:chemistry*; D016062:Porosity
chemical_list: D011108:Polymers
keywords: Bio-electrode; Bioelectric signal; Dry electrode; EEG; Polymer wick