Thermochromic and conductive hydrogels with tunable temperature sensitivity for dual sensing of temperature and human motion

Abstract

Skin-like body sensors have important applications in soft-bodied intelligent robots, electronic skins, and medical health monitoring.

Latest developments and trends in electronic skin devices

“…Xie et al prepared Chitosan/poly(acrylic acid-co-acrylamide)/MXene@polyethyleneimine [CS/P(AA-co-AAm)/MXene@PEI]/Fe 3+ +Cu 2+ nanocomposite bi-network hydrogels by thermal cross-linking, which exhibited excellent properties (including 2.64 MPa tensile strength, 689% elongation at break, 10.25 MJ•m -3 toughness and 1.89 S•m -1 conductivity) [94] . Sensors made with this hydrogel can achieve linear sensing over a strain amplitude of more than 300%, showing excellent potential for diverse applications [Figure 6B].…”

“…Although ionic hydrogel-based strain sensors have the advantages of good flexibility, biocompatibility, and excellent strain sensing performance, their environmental stability has been an intractable problem due to the volatilization, evaporation, and coagulation of the aqueous solvents in the hydrogel, limiting their ; (B) Schematic structure and main properties of CS/P(AA-co-AAm)/MXene@PEI/Fe 3+ +Cu 2+ nanocomposite dual network hydrogel [94] ; (C) the opaque/transparent transition of SN-PAAM dualresponsive ion-conducting hydrogel [95] . KPS: Potassium persulfate; TMEDA: tetramethylethylenediamine; CS/P(AA-co-AAm)/MXene@PEI: Chitosan/poly(acrylic acid-co-acrylamide)/MXene@polyethyleneimine; SN-PAAM: sodium dodecyl sulfatemodified poly(acrylamide) hydrogel.…”

Fabrication and Performance of Multisensory Flexible Hydrogel toward Strain, Temperature, and Flame Sensing

“…For instance, Sun et al 20 introduced both Ni 2+ and Al 3+ bimetal ions into PAM/PAA hydrogels, resulting in hydrogels with outstanding toughness (813 kJ/m 3 ) and conductivity, making them suitable for detecting human motion. Lei et al 21 integrated sodium dodecyl sulfate (SDS) into polyacrylamide (PAM) hydrogels, resulting in sensors characterized by exceptional tensile strength (581 kPa), remarkable elongation (1836%), and a highly responsive reaction to both strain and temperature stimuli. Wang et al 22 combined gelatin-modified MXene with PAM hydrogels to create a hydrogel with high strength (430 kPa), significant extensibility (1100%), and excellent adhesion, enabling measurement of human body temperature and detection of various movements.…”