Elastomer
conductive composites (ECCs) are wonderful candidates
for stretchable strain sensors. However, the sensitivity of ECC-based
flexible strain sensors is limited in low-strain range, the main working
range for human movements, due to the insignificant geometric change
of the sample shape and weak tunneling effect of the conductive network.
Herein, bioinspired heterogeneous thermoplastic polyurethane (TPU)/carbon
black (CB) composites (TCs) are assembled by hot pressing two TCs
with different Young’s moduli in series. The modulus of the
TCs is controlled by the CB content, Young’s modulus of TPU,
and plasticizer content. Experimental results and finite element analysis
(FEA) confirm that the low Young’s modulus component undergoes
higher strain compared with the high Young’s modulus component,
resulting in a more serious change of the conductive network and higher
gauge factor (GF) values. Compared with homogeneous TCs, the GF of
heterogeneous TCs was improved by a factor of 20.7 and 9.6 in the
low-strain (0–6%) and high-strain range, respectively. The
relationship between modulus variety and GF is quantitatively described,
and the GF values depend on the Young’s modulus of the individual
components. Constructing a heterogeneous structure with different
Young’s moduli is a valuable and facile way to increase the
sensitivity of ECC-based flexible strain sensors.