Electrophoretic deposition of carbon nanotubes onto glass fibers for self-sensing relaxation-induced piezoresistivity of monofilament composites

Electrophoretic deposition (EPD) in water using a continuous filament process was used to modify E-type glass fibers (GFs) by depositing multiwall carbon nanotubes (MWCNTs) onto their surface. The oxidized MWCNTs behaved as negatively charged particles and migrated toward the positive electrode, containing the GFs. This electrokinetic motion was confirmed by measuring the point of zero charge and Z-potential. The influence of the main EPD parameters on the morphology and electrical properties of the MWCNT-coated GFs is investigated. The most uniform coverage was achieved by using an electric field of 4.5 kV/m for 30 min under a warm bath temperature (~ 50 °C). Higher intensity of the electric field or longer deposition times was not beneficial for the homogeneity of the deposit. The application of these electroconductive MWCNT-modified fibers as smart materials was demonstrated by conducting relaxation-induced piezoresistive experiments in monofilament polymer composites using these MWCNT-modified fibers.