Technologies described herein are generally related to systems and processes for repairing a graphene membrane on a support. A chamber may receive a layer of graphene on a support. The layer of graphene may include a hole. A first container including an initiator may be effective to apply an initiator through the hole to the support to functionalize the support and produce an initiator layer on the support. A second container including an activator may be effective to apply an activator through the hole to the initiator layer to activate the initiator layer. The application of the activator may further be effective to grow a polymer from the initiator layer. The growth of the polymer may be effective to produce a polymer plug in the hole and effective to repair at least a portion of the layer of graphene.