Shear rheological properties of PF127 with HPAA additives. A) Schematic of the shear rheometer. B) Steady-state flow curves indicating consistent yield stress $τy$ across varying concentrations of HPAA additives. The solid line represents a fit to the Herschel–Bulkley model. C) Temperature sweeps showing the gelation temperature $Tg$⁠, indicating no shift in gelation point due to HPAA additives. Comparative data of flow curves and temperature sweeps for PEO additives are provided in Supplementary Material Appendix, Figure S8. D) Strain amplitude sweep at an angular frequency $ω=1$ rad/s (main figure) and frequency sweep at a strain amplitude $γ=0.2%$ (inset) reflecting no change in the viscoelastic moduli $G′$ (filled symbols) and $G″$ (empty symbols) at different HPAA concentrations. E) Strain stiffening ratio S, illustrating the transition from a linear elastic response at low strains (⁠$S≈0$⁠) to notable strain stiffening when S increases with the strain amplitude γ beyond the linear viscoelastic regime (LVR). F) Energy dissipation ratio ϕ, showing the shift from elastic behavior (⁠$ϕ≈0$⁠) at smaller strain amplitudes to near-ideal plastic response (⁠$ϕ≈1$⁠) at larger amplitudes. LAOS measurements in Fig. 2E-F are carried out at $ω=3$ rad/s. Except for Fig. 2C, the temperature is set to $26∘$C for all tests. Numbers in the legend of Fig. 2B-F refer to the weight percentage of HPAA additives.