## 1 Introduction
Compared with epoxy materials, the thermal stability and mechanical properties of nano-ZnO loaded graphene oxide/epoxy composites have been significantly improved. [PERSON] et al. [11] found that used KH550 modified nano-TiO\({}_{2}\) on the surface of GO to synthesized TiO\({}_{2}\)-GO composite material, which could effectively improve the corrosion resistance of the epoxy resin by dispersing in epoxy resin coating. In order to further improve the compatibility of GO and resin, enhance the macroscopic properties of GO/epoxy composites. Using an organic reducing agent (polyethylene glycol [18], isocyanate [19], dopamine [20], etc.) to interact with the reactive functional groups on the surface GO, through the intercalation and coating of the GO sheet to restraining agglomeration, and functionalization of GO [21], which has been confirmed as an effective method to enhance the interaction between GO and resin matrix and improve the compatibility between GO and resin. At the same time, making interfacial adhesion between the GO and polymer composites is improved and the macroscopic properties of the GO/polymer composite are enhanced. Among them, dopamine, as a green environmentally friendly reducing agent, can be easily deposited on the surface of many organic and inorganic substrates by self-polymerization and covalent bonding to form a polydopamine layer. Moreover, abundant reactive functional groups (such as catechol, amines, and mines) in dopamine and polydopamine can be used as active sites for covalent modification with desired molecules [22; 23; 24]. [PERSON] et al. [21] found that DA could effectively eliminate the labile oxygen functionality of GO and generate polydopamine functionalized graphene oxide (PDA-GO), because of DA would be oxidated and undergo the rearrangement and intermolecular cross-linking reaction to produce polydopamine (PDA), which would improve the interfacial adhesion between GO and epoxy, and further beneficial for the homogenous dispersion of GO in epoxy matrix to enhance the thermal conductivity, storage modulus, and mechanical properties of epoxy. [PERSON] et al. [25] reported an eco-friendly anticorrosive water-borne epoxy coating incorporated with the dopamine functionalized GO nanosheets, and found that the GO-PDA nanosheets had superior compatibility with waterborne epoxy matrix. The electrochemical results showed that the corrosion protect ion performance of GO-PDA/EP was improved with respect to the blank EP and GO/EP, owing to the strong interfacial bonding between GO-PDA and EP matrix. In this paper, dopamine was used to covalently modify graphene oxide to form a polydopamine (PDA) layer with excellent adhesion with GO surface, and nano-TiO\({}_{2}\) particles were firmly deposited on the surfaces of the graphene oxide (GO) via the electrostatic and hydrogen interactions forming nano-PDA@GO-TiO\({}_{2}\) composites. Adding it to the waterborne epoxy coating with the help of ultrasonic dispersion method, and systematically studied the basic physical properties and corrosion resistance of the nano-PDA@GO-TiO\({}_{2}\) composites with different contents on the impact resistance, hardness, and adhesion of the waterborne epoxy coating. The effects of corrosion resistance and corrosion resistance of nano-PDA@GO-TiO\({}_{2}\) composites waterborne epoxy coatings (PGT/WEP) were also investigated by electrochemical experiments.