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With the increasing demand for recycling composite materials and re-use of fibers and matrices as new resources in the context of a circular economy, composite materials often pose problems as they form complex aggregates. The user properties of high strength and long lifetime require strong interfaces between a matrix and reinforcing fibers, while recycling would benefit from easy separation of the two phases. Therefore, the design of an interface with reversible bonding upon thermal or chemical activation may offer a good balance. In addition, the request for bio-based composites incorporating cellulose fibers should be combined with bio-inspired interface modification avoiding traditional chemical surface modification. An impressive example of reversible bonding in nature is observed in mussels and is regulated by the so-called mussel foot proteins. The latter includes dopamine as a main component that presents reversible bonding upon a change in pH. In the present work, cellulose fibers were modified with a dopamine (DA) or polydopamine (PDA) coating that was polymerized when in contact with the cellulose surface, thus providing good chemical compatibility and interaction with cellulose hydroxyl groups. The adhesive properties of the modified cellulose fibers were investigated via local adhesive measurements using atomic force microscopy and varied between strong adhesion (low pH) and weak adhesion (high pH). In parallel, the macroscale mechanical strength of the epoxy composites with modified fibers improved, while the interface adhesion of the modified fibers dropped after submersion in solutions with pH = 9.8. Based on these observations, a proof of concept for recycling of cellulose/epoxy composites and recovery of cellulose fibers is demonstrated after grinding and chemical treatment at a high pH.