Shear-thickening materials have been widely applied in
fields related
to smart impact protection due to their ability to absorb large amounts
of energy during sudden shock. Shear-thickening materials with multifunctional
properties are expanding their applications in wearable electronics,
where tactile sensors require interconnected networks. However, current
bifunctional shear-thickening cross-linked polymer materials depend
on supramolecular networks or slightly dynamic covalently cross-linked
networks, which usually exhibit lower energy-absorption density than
the highly dynamic covalently cross-linked networks. Herein, we employed
boric ester-based covalent adaptive networks (CANs) to elucidate the
shear-thickening property and the mechanism of energy dissipation
during sudden shock. Guided by the enhanced energy-absorption capability
of double networks and the requirements of the conductive networks
for the wearable tactile sensors, tungsten powders (W) were incorporated
into the boric ester polymer matrix to form a second network. The
W networks make the materials stiffer, with a 13-fold increase in
Young’s modulus. Additionally, the energy-absorption capacity
increased nearly 7 times. Finally, we applied these excellent energy-absorbing
and conductive materials to bifunctional shock-protective and strain
rate-dependent tactile sensors. Considering the self-healable and
recyclable properties, we believe that these anti-impact and tactile
sensing materials will be of great interest in wearable devices, smart
impact-protective systems, post-tunable materials, etc.