New strategy for enhancing interfacial adhesion between carbon fiber and epoxy by using mussel-inspired polydopamine-Fe complex nanospheres

The liable interfacial delamination of carbon fiber composites is a long-lasting problem that restricts its widely application. One promising route is to hybridize fiber with nano-particles on account of their prominent mechanical properties and huge specific surface area, while trial using biobased nanoparticles are in its infancy. Mussel adhered firmly to the reef relies on its bushy byssal threads, which correlates with chelation of ferric ions with catechol-containing proteins. Inspired by this, we deposited synergistic bio-based polydopamine (PDA)-Fe complex nanospheres and silane coupling agent on carbon fiber by simply impregnation, which delivers increment of 56.4% in interfacial shear strength (IFSS) in epoxy matrix relative to untreated fiber composites. Results suggest that the improved epoxy wetting behavior that imparts full infiltration, the excellent adhesivity that eliminates weak interface layer, as well as strong but reversible PDA-Fe chelate crosslinks that advance tress transfer and energy dissipation, which are critical to IFSS growth. This work provides a new and attractive bio-nanomaterial of PDA-Fe in interfacial engineering of composites.