Fig. 5. Shear rate–dependent behavior and viscosity of jammed granular hydrogels are affected by microgel properties.

(A) Rotational shear rate measurements were performed (δγ/δt = 10⁻⁵ to 10⁻¹ s⁻¹, 25°C). All materials demonstrated a Newtonian plateau at low shear rates and a decrease in viscosity, η, with increasing shear rate. Granular hydrogels with stiff microgels (E = 120 kPa, Ø = 55 μm, dark blue) showed a rapid decrease in η, while soft building blocks (E = 20 kPa, Ø = 55 μm, light blue) resulted in a Newtonian plateau for an extended range of shear rates. (B) Zero-shear viscosity, η₀, of granular hydrogels scaled over two orders of magnitude with an increase in polymer weight percentage of building blocks, as shown for Ø = 55 μm (blue) and Ø = 100 μm (red) microgels (P < 0.001). (C) η₀ varied at E = 120 kPa (dark blue; P < 0.05) and remained constant for E = 20 kPa (light blue; ns) with changes in microgel size. (B and C) Plots are represented as means ± SEM, n = 3. Statistical analysis was performed using one-way ANOVA with Tukey’s test for post hoc analysis.