Figure 3.

(a) The storage G′ and loss G″ moduli of PTFe-1 hydrogels with angular frequency sweeps between 0.1 and 100 rad s^–1. (b) Critical gelation pH of PTFe hydrogels. (c) Storage modulus (G′) of PTFe hydrogels plotted as a function of pH at an angular frequency of 25 rad s^–1 and a strain of 1%. (d) Storage modulus chart for various catechol-based hydrogels in different pH values. Hydrogels include the gel prepared in this work marked as red (acidic part), catechol-based chitosan hydrogels as green,^29,30 gelatin/thiourea/catechol hydrogels as purple,³¹ catechol-based 4- or 8-arm polyethylene glycol (PEG) hydrogels as yellow,^9,32,33 catechol-based protein or peptide hydrogels as dark gray,^34,35 and catechol-based polyallylamine (PAA) hydrogels as blue.³⁶