One-step hydrothermal synthesis of reduced graphene oxide/aspartic acid intercalated layered double hydroxide for enhancing barrier and self-healing properties of epoxy coating

摘要

Self-healing coatings, possessing an "active healing" ability to repair physical damage and to prolong the life of coating without external intervention, are of current interest. Herein, a novel self-healing coating, by using aspartic acid intercalated layered double hydroxide (AA-LDH) @ reduced graphene oxide (RGO) as filler within epoxy has been demonstrated. The corrosion protection performance and self-healing ability of composites coatings have been investigated via electrochemical impedance spectroscopy (EIS) and salt spray test. The AA-LDH@RGO/epoxy exhibits excellent corrosion resistance owing to the high barrier properties of RGO for corrosive ions. Moreover, the epoxy loaded with AA-LDH@RGO shows outstanding self-healing performance, attributing to the release of AA from LDH on the basis of the ion exchange performance, thus leading to formation of AA-Fe-AA compounds at the coating/ steel interface. The results clarified that the addition of AA-LDH@RGO increases the impedance of the epoxy resin from 6.437 x 10(6) to 2.112 x 10(9) Omega cm(2), and effectively extends the epoxy coating failure time to 40 days.