Extended Data Fig. 1: The reverse gel-point concept used to derive the model of degradable thermosets shown in Fig. 1b.

a, A thermoset network containing f potential crosslinks per strand, c actual crosslinks per strand and x cleavable bonds within each strand may or may not be degraded into soluble fragments after bond cleavage. A model that determines whether the material will dissolve can be described as a function of f, c and x (Fig. 1b). b, The reverse gel-point concept enables this model by assuming that the minimum x required to enable thermoset degradation for given c and f values corresponds to the value that will inhibit the gelation of degradation fragments derived from strands with f potential crosslinking sites and x cleavable bonds. We use existing gelation theories (Miller–Macosko and Flory–Stockmayer) to solve for x, given f and c. Key to the reverse gel-point concept is the assumption that the network structure formed by the crosslinking of linear copolymer strands followed by cleavage of degradable bonds in those strands is identical to the network formed by first cleaving the linear copolymer strands and then crosslinking the resulting degradation products.