Since the film growth chemistry revolves around the reactive sites on the film, we represent the film growth chemistry using a variant of fragment-based modeling, where the reactive sites on the film are lumped as reactive fragments participating in the liquid/solid interface reactions as reactants and/or products. In order to incorporate new types of reactive sites on film due to autoxidation chemistry, new fragments are defined. The reactive fragments considered in the oxygen-perturbed fouling model are the carbon-carbon double bond (CDB), the allylic hydrogen (AH), the allylic radical (AR), the alkyl radical (KR), the carbon peroxide (CP), the hydroperoxide (HP), the peroxyl radical (PR), and the alkoxyl radical (OR), as shown in Fig. . A representative structure is assigned to each fragment for estimating its thermochemistry using methods described in Sec. The effects of the truncated liquid-phase oligomers on fouling growth are recovered using a fragment-based modeling approach. We consider the reactions between the functional groups on the heavy tail of liquid-phase oligomers and the reactive site on the solid, instead of using the heavy-chain oligomers explicitly, to prevent an over-complicated model while maintaining interpretability. The steady-state concentration of the functional groups on the heavy tail of liquid-phase oligomers in each tray is estimated using α and w(k), which is elaborated in Sec. S2.7.