Figure 4.

(a) frequency sweeps with a strain of 1.0% of the single/double DCBs-crosslinked hydrogels; storage modulus of double DCBs-crosslinked hydrogels at 2 h (bottom) and 48 h (whole) during the gelation with different composition and copolymer concentrations, the molar ratios of ketone to hydrazine is fixed to 1.0, (b) mass ratios of PVA to PAD are fixed to 0.5 and (c) mass ratios of PVA to PAD are fixed to 0.1. All the experiments were performed at a frequency of 1.0 Hz and a strain of 1.0%; (d) tensile tests of single/double DCBs-crosslinked hydrogels. The stretching rate of the samples is 50 mm min⁻¹.