Fig. 4: Integrated properties of the RHOCF.

a The optical property of the control and RHOCF samples. Although the control was opaque, the RHOCF exhibited an optical transmittance of 96.32%. b The Nyquist plot of as-prepared samples demonstrated that the enhanced conductivity of RHOCF arisen from the synergistic interaction between bismuth ions and the zwitterionic channels. c DSC tests of pure hydrogel, hydrogel containing glycerol (Control sample), and hydrogel containing glycerol/bismuth ions (RHOCF sample). d The schematic illustration of molecular interaction between ions/glycerol and water molecules, indicating the anti-freezing mechanism. e Shear strength and interfacial toughness of the RHOCF to various substrates. The circular dots of the histogram represented the measured data points of five. Data are presented as mean ± standard deviation from n   =   5 independent samples.