Interphases in fibre-reinforced composites are vital regions for the stress transfer between fibres and surrounding matrix. Adding an electrical percolated network into the interphases allows the detection of mechanical stress strain behavior by monitoring its electrical response. To create an electro-mechanical-response sensing ability of fibres by a continuous surface nanocoating, highly conductive nanomaterials are needed. Therefore, a comparison of the electro-mechanical-response behavior of different carbon modification, such as fibre like (carbon nanotubes), sheet like (graphene) and spherical (carbon black) modifications, were performed. The fillers where stabilized in aqueous polypropylene (PP) emulsion. Due to the additive excess of the initial PP emulsion, the respective carbon fillers can be easily stabilized by using an ultrasonic supported dispersion unit. Subsequently, the carbon filled PP emulsions were used for the in-line nanostructuring of the glass fibres during the melt drawing process. In order to achieve a homogeneous electrical conductive interphase, the average coating thickness must be above 450nm. Additionally, the temperature and the drawing speed of the coating process have a high impact on resulting electrical resistivity. For the determination of the strain-sensing behavior of the nanostructured glass fibres in PP composites, a mechanical 3-point bending test was chosen. In a static test assembly, the online resistance measurement shows a clear correlation between the measured electrical signal and the applied mechanical deformation.