Acryloyl chitosan as a macro-crosslinker for freezing-resistant, self-healing and self-adhesive ionogels-based multicompetent flexible sensors.

Here, a polysaccharide derivative acryloyl chitosan (AcCS) is exploited as macro-crosslinker to synthesize a novel ionogel poly (acrylic acid-co-1-Vinyl-3-butyl imidazolium chloride) (AA-IL/AcCS) via a one-pot method. AcCS provides abundant physical and chemical crosslinking sites contributing to the high mechanical stretchability (elongation at break 600 %) and strength (tensile strength 137 kPa) of AA-IL/AcCS. The high-density of dynamic bonds (hydrogen bonds and electrostatic interactions) in the network of ionogels enables self-healing and self-adhesive features of AA-IL/AcCS. Meanwhile, AA-IL/AcCS exhibits high ionic conductivity (0.1 mS/cm) at room temperature and excellent antifreeze ability (-58 °C). The AA-IL/AcCS-based sensor shows diverse sensory capabilities towards temperature and humidity, moreover, it could precisely detect human motions and handwritings signals. Furthermore, AA-IL/AcCS exhibits excellent bactericidal properties against both gram-positive and gram-negative bacteria. This work opens the possibility of polysaccharides as a macro-crosslinkers for preparing ionogel-based sensors for wearable electronics.

Semi-IPN ionogel based on poly (ionic liquids)/xanthan gum for highly sensitive pressure sensor.

In this paper, a novel ionogel with semi-interpenetrating poly (ionic liquids)/xanthan gum (PIL/XG) polymer network (semi-IPN) was prepared by using a simple one-pot method. The structure and the pressure sensing performance have been systematically investigated. It was found that introducing a low content (0.3-3.1 wt%) of XG significantly promoted the mechanical performance of ionogels with little effect on the ionic conductivity. The optimized PIL/XG containing 2.2 wt% XG exhibited high compression strength (761.0 kPa) and ionic conductivity (0.63 S/m at 25 °C). Such ionogels showed a liner response (0-100 kPa) and high sensitivity value of 6.86 kPa-1 in a capacitive mode. Meanwhile, as a resistive sensor, PIL/XG exhibited a wide response range to dynamic pressure ranges with stable repeatability. Furthermore, this ionogel exhibited excellent bactericidal properties against both gram-positive bacteria and gram-negative bacteria. This research provides a potential approach for developing ionogels based on semi-IPN with pressure-sensitive and anti-bacterial properties.