posted on 2024-01-18, 11:04authored byRitvika Kushwaha, Souradeep Dey, Kanika Gupta, Biman B. Mandal, Debapratim Das
A new conductive and transparent organohydrogel is developed
with
high stretchability, excellent mechanical, self-healing, antifreezing,
and adhesive properties. A simple one-pot polymerization method is
used to create polyacrylamide cross-linked through N,N′-methylenebis(acrylamide) (MBAA) and divinylbenzene
(DVB). The dual chemical cross-linked gel network is complemented
by several physical cross-links via hydrogen bonding and π–π
interaction. Multiple chemical and physical cross-links are used to
construct the gel network that allows toughness (171 kPa), low modulus
(≈45 kPa), excellent stretchability (>1100%), and self-healing
ability. The use of appropriate proportions of the water/glycerol
binary solvent system ensures efficient environment tolerance (−20
to 40 °C). Phytic acid is used as a conductive filler that provides
excellent conductivity and contributes to the physical cross-linking.
Dopamine is incorporated in the gel matrix, which endows excellent
adhesive property of the gel. The organohydrogel-based strain sensors
are developed with state-independent properties, highly linear dependence,
and excellent antifatigue performance (>100 cycles). Moreover,
during
the practical wearable sensing tests, human motions can be detected,
including speaking, smiling, and joint movement. Additionally, the
sensor is biocompatible, indicating the potential applications for
the next generation of epidermal sensors.