The manuscript by Varcoe and coworkers reported a systematic study to reveal the influence of polyethylene (PE) crystallinity on the properties of radiation-grafted anion-exchange membranes (AEMs). By annealing the PE at 115 °C before radiation graft, the high crystallinity gave rise to membranes with high conductivity and good fuel cell performance. The authors also provided very detailed characterization and explanation. My only concern about this manuscript is the durability of the AEM under operating conditions. On the one hand, alkaline stability of the benzyltrimethyl-ammonium cation is a common concern in the field of AEMs. On the other hand, although PE has high Tm, its intrinsic Tg is low. Thus, after radiation graft and quaternization, the long-time operating at high temperatures may lead to chain movement. Is it possible that the influence of crystallinity may become less significant after high temperature durability test? After including the discussion about durability, I recommend this manuscript to be published in Journal of Materials Chemistry A.

The authors have effectively addressed the reviewers' concerns. The paper is therefore acceptable for publication.