Chain-scissions in the simulation was restricted to chains with more than one monomeric unit (ni > 1). For each selected chain with length nj , a reaction and thus cutting point cj (where cj ∈ (nj -1) cutting positions) was randomly identified in the simulation. The probability of cj to be chosen was uniformly distributed between 1 and nj -1, ensuring that the scission produces two new viable segments (i.e., reaction products). The lengths of these reaction products were nc and nj-nc. The probability of chain j with length nj to be chosen for scission, P(nj), is proportional to the continuous rate constant 𝑘 D for reaction of PEG and • OH and thus depends on the number of repeating monomeric units n as rationalized above, and thus defined as (Equation ):