Self-adhesive and anti-fatigue cellulose-polyacrylate ionogels prepared by ultraviolet curing used as biopotential electrodes

Conductive hydrogels have been extensively studied because of flexibility and skin-like capability to be used as biopotential electrodes for wearable health monitoring. However, they may suffer from poor mechanical prop-erties and stability problems when used in practical applications caused by water evaporation. Herein, we prepared self-adhesive, transparent, flexible and robust ionic gels that can conformal contact with the skin used as biopotential electrodes for precise health monitoring. Cellulose based iogels were prepared by dissolving cellulose using [Bmim]Cl at 100 C followed by in situ Ultraviolet light photopolymerization of acrylic acid by adding a mixture of acrylic acid and 2-hydroxy-2-methylpropiophenone. Cellulose/polyacrylic acid-based ionic gels-2 (BCELIG-2) has a Young's modulus of 0.2 MPa, a strain at break of 226 %, a modulus of elasticity of 0.1 MPa, and a toughness of 22.5 MJ m- 3. Fixing the strain at 40 %, the ionic gels can recover to their original length after ten tensile-unloading cycles. They can accurately detect subtle physical motions such as arterial pulsations, which can provide important cardiovascular information.