Fig. 1. Concentrated suspensions of microgel building blocks give rise to rigidity on the macroscale with shear-thinning and self-healing properties.

(A) Microgel building blocks formed via a microfluidic templating method, in which droplets of polymer solution [water-(W)-in-oil (O)] were collected, cross-linked, and subsequently jammed into granular hydrogels. (B) Macroscale hydrogels were produced owing to the microgel contacts in the jammed state. (C) The granular hydrogels [10 wt %, Ø = 55 μm microgels] exhibited rapid and reversible self-healing as shown via step-strain measurements with alternating intervals at low (γ = 0.5%) and high (γ = 500%) applied strain at constant angular frequency (ω = 10 rad s⁻¹). Closed and open symbols represent the storage moduli G′ and loss moduli G″, respectively. (D) The properties of the microgel building blocks controlled the linear and nonlinear mechanical response of the formed granular hydrogels.