This study presents a comprehensive investigation on
the fabrication
and characterization of piezoresistive elastomeric strain sensors
using multiwalled carbon nanotubes (MWCNTs) incorporated into a silicone
rubber matrix. Through meticulous experimentation and theoretical
modeling, the study elucidates the intricate relationship between
MWCNT concentration, mechanical properties, and electrical conductivity
within the composite materials. The research reveals that composite
formulations with MWCNT concentrations slightly above the percolation
threshold exhibit superior strain-sensing properties. Specifically,
composites containing 2 phr of MWCNTs demonstrate a remarkable gauge
factor of 225, indicating enhanced sensitivity compared with higher
MWCNT loadings. Mechanical testing using a tensile testing machine
elucidates the complex interplay between MWCNT loading and tensile
properties. However, subsequent enhancements in tensile properties
with increasing MWCNT content suggest improved dispersion and reinforcing
effects, highlighting the potential for tailored mechanical performance.
The investigation of DC conductivity demonstrates a significant increase
with rising MWCNT concentrations, indicative of the formation of conductive
networks as MWCNTs reach the percolation threshold. Enhanced charge
transport and constructive interface interactions facilitate efficient
electron flow through the composite, which is crucial for applications
requiring electrical conductivity. Moreover, the analysis of dielectric
permittivity reveals its concentration-dependent increase, attributed
to the large surface area of MWCNTs promoting stronger interactions
with the matrix and enhanced polarization under electric fields. Drastic
changes in AC conductivity at lower frequency levels within the percolation
region suggest influences of dielectric relaxation, polarization effects,
and formation of conductive paths. This study underscores the potential
of MWCNTs-silicone rubber composites as versatile materials for advanced
strain-sensing applications, offering tunable mechanical and electrical
properties tailored to specific requirements.