Conductive hydrogels have attracted extensive interest
owing to
its potential in soft robotics, electronic skin, and human monitoring.
However, insufficient mechanical properties, lower adhesivity, and
unsatisfactory conductivity seriously hinder potential applications
in this emerging field. Herein, a highly elastic conductive hydrogel
with a combination of favorable mechanical properties, self-adhesiveness,
and excellent electrical performance was achieved by the synergistic
effect of aminated lignin (AL), polydopamine (PDA), polyacrylamide
(PAM) chains, and biomass carbon aerogel (C-SPF). In detail, AL was
applied to induce slow oxidative polymerization of DA for preparing
the sticky hydrogel containing PDA. Then, C-SPF carbon aerogel was
used as a matrix to construct a dual-network structured composite
hydrogel by combining with the hydrogels derived from PDA, AL, and
PAM. The as-prepared conductive hydrogel displayed excellent mechanical
performance, strong adhesive strength, and repeatable adhesivity.
The prepared hydrogel-based pressure sensor possessed fast response
(0.6 s loading and 0.8 s unloading stress time), high response (maximum
RCR = 1.8 × 104), wide working pressure range (from
0 to 240.0 kPa), and excellent durability (stable 500 compression
cycles with 30% deformation). In addition, the prepared sensor also
displayed ultrahigh sensitivity (170 kPa–1), which
was near 4 orders of magnitude higher than the conventional lignin-modified
PAM hydrogels. The multiple interactions between hydrogel components
and the mechanical properties of hydrogel were also verified by molecular
dynamics investigation. Moreover, the excellent cytocompatibility
and antibacterial activity of this composite hydrogel ensured high
potential in various applications such as human/machine interaction,
artificial intelligence, personal healthcare, and wearable devices.
