Self-healing polymeric ionic liquid hydrogels with high mechanical strength and ionic conductivity

The poor mechanical properties of self-healing hydrogels limited their applications in the fields of biomedicine and industry. Here, a series of self-healing polymeric ionic liquid (PIL) hydrogels with high mechanical strength and electrical conductivity were prepared through hydrophobic association. Hydrophilic monomer vinyl ionic liquids (VILs) based on choline and amino acids, acrylamide (AAm) and hydrophobic monomers stearyl methacrylate (C18) were copolymerized in a micellar solution of sodium dodecyl sulfate (SDS); meanwhile, bacterial cellulose was introduced to enhance the mechanical strength of hydrogels. The resultant hydrogels exhibited excellent mechanical strength (5.8 MPa), extensive elongation at break (4250%) and outstanding self-healing efficiency (85%) without any external intervention. Even after healing, the tensile strength of most hydrogels could reach 2.5–3.9 MPa. At the same time, the incorporation of ILs endowed hydrogels with good electrical conductivity (a maximum of 1.258 S/m). These excellent properties predicted the potential application of the obtained PIL hydrogels in the fields of biomedicine and industry.