FABRICATION AND ELECTRICAL PROPERTIES OF CUP-STACKED CARBON NANOTUBES/POLYMER NANOCOMPOSITE FILMS AS AN ELECTRODE SENSOR FOR BRAIN-WAVE DETECTION

Polymer-based composites films with cup-stacked carbon nanotubes (CSCNTs) are fabricated with objectives to enhance the electrical sensitivities to detect brain-waves without disturbing electroencephalography- computed tomography (EEG-CT) imaging. CSCNTs are homogeneously dispersed in pre-polymer of polysiloxane using a high speed mixer at rotation speed of 1500rpm for 1h after ultrasonic treatment for 30 min. The pre-polymer suspension including CSCNTs fillers was casted on the polyimide spacer and underwent air removal by vacuum treatment, and dried for 2h at 80 degrees C to confirm complete curing. The electrical resistivity of the composites was evaluated by using four point probe method. The cross-section of the sample was observed by SEM microscope and digital microscope. The artifact effect of the composite films under X-ray environment was evaluated by X-ray CT scanning. Effects of solvent and vacuum treatment are performed during fabrication in order to motivate denser packing of the nano inclusions reducing inter-phase gaps in the matrix. X-ray transmission, electric resistivity and pressure sensitiveness are analyzed for evaluation of the internal structure variation and enhancement of physical properties of the composites. Analysis shows that the composite films enhance the X-ray transmission as well as high electrical conductivity without harmful effects to human body, which makes CSCNTs hybrid film as a promising material for EEG-CT recording system.