High-barrier and corrosion-inhibiting epoxy composite coatings with mussel-inspired hexagonal boron nitride-based nanocontainers

Hexagonal boron nitride (h-BN) nanosheets with high impermeability and electrical insulating properties present great value in improving the anti-corrosion properties of organic coatings. Yet, single h-BN incorporated organic coatings with only passive barrier properties fail to provide long-term corrosion protection upon damage without timely repairs. Thus, developing novel anti-corrosive coatings that combine exceptional passive barrier properties with active corrosion-inhibiting capabilities is particularly interesting. Herein, we synthesized h-BN-based nanocontainers by constructing a mesoporous polydopamine layer on the h-BN surface to encapsulate benzotriazole molecules (mBN@BTA), aiming to impart both physical barrier and corrosion-inhibiting effects to h-BN nanosheets. When mBN@BTA nanocontainers are incorporated into epoxy (EP) matrix, the resulting mBN@BTA/EP/steel system exhibits outstanding long-term protective performance under intact status and remarkable corrosion-inhibiting capabilities under damaged status, as demonstrated by high |Z| f ​=  ​ 0.01Hz value of 3.7 ​× ​10 10  ​Ω ​cm 2 after 160 d of exposure in 3.5 ​wt% NaCl solution and low admittance value (7.59 ​× ​10 −8  ​Ω −1  ​cm −2 ) in the damaged region. This work represents a significant advancement in the utilization of h-BN nanomaterials for anti-corrosion coatings.