Conductive hydrogels have been increasingly employed
to construct
wearable mechanosensors due to their excellent mechanical flexibility
close to that of soft tissues. In this work, piezoelectric hydrogels
are prepared through free radical copolymerization of acrylamide (AM)
and acrylonitrile (AN) and further utilized in assembling flexible
wearable mechanosensors. Introduction of the polyacrylonitrile (PAN)
component in the copolymers endows the hydrogels with excellent piezoelectric
properties. Meanwhile, significant enhancement of mechanical properties
has been accessed by forming dipole–dipole interactions, which
results in a tensile strength of 0.51 MPa. Flexible wearable mechanosensors
are fabricated by utilizing piezoelectric hydrogels as key signal
converting materials. Self-powered piezoelectric pressure sensors
are assembled with a sensitivity (S) of 0.2 V kPa–1. Additionally, resistive strain sensors (gauge factor
(GF): 0.84, strain range: 0–250%) and capacitive pressure sensors
(S: 0.23 kPa–1, pressure range:
0–8 kPa) are fabricated by utilizing such hydrogels. These
flexible wearable mechanosensors can monitor diverse body movements
such as joint bending, walking, running, and stair climbing. This
work is anticipated to offer promising soft materials for efficient
mechanical-to-electrical signal conversion and provides new insights
into the development of various wearable mechanosensors.