(a) The effect of polymer chain length (measured by the number of repeated polymeric units, n) of the H(AB)n sequences on simulated steady-state polymer network properties, and the corresponding Young’s modulus before and after shear flow. All three polymer network properties correlate well with the value of n, except that the network conductance remains zero for shorter chain length (n=2 and 4) after shear flow due to shearing-induced perturbations. The Young’s modulus also correlates well with the value of n, except that, for n=2 and 4, the mechanical values remain zero after shear flow, as a result of discontinuous networks with zero conductance. (b) Correlations between total number of bridges and conductance of the H(AB)n sequences with simulated Young’s modulus. The total number of bridges correlates with the Young’s modulus before shear flow, but cannot explain the zero values for shorter chains (n=2 and 4) after shear flow. On the other hand, the network conductance correlates perfectly well with the Young’s modulus both before and after shear flow, representing an extension of the classical polymer theory to heterogeneous fibres (see Supplementary Fig. 8).