Shape Memory Effect Self-Healing Coating Based On Polypyrrole@Polydopamine Photothermal Conversion

Photoinduced shape memory self-healing coatings is a kind of shape memory self-healing coatings,which has the characteristics of local repair,non-contact and remote control.In this paper,a near-infrared light responsive shape memory effect self-healing coating is prepared,in which epoxy resin(EP)is used as the shape memory matrix,boron nitride nanosheets(BNNS)and graphene(Gr)are used as thermally conductive fillers,and polypyrrole@polydopamine(PPy@PDA)is used as a photothermal agent.The influence of molten alkali on the thickness of BNNS is investigated by changing the molar ratio of molten alkali sodium hydroxide(Na OH)and potassium hydroxide(KOH),and the effect of the amount of BNNS and Gr on the thermal conductivity of epoxy resin is studied.The results show that when the ratio of sodium hydroxide:potassium hydroxide is 2:1,the thickness of BNNS obtained is the smallest,and when BNNS:Gr is 1:4,the thermal conductivity of epoxy resin can be increased by90.7%,and the thermal conductivity and shape memory efficiency are the best.When praparing PPy@PDA,adjusting the molar ratio of dodecylbenzenesulfonic acid(DBSA),the ratio of PPy and dopamine(DA)to study the effect of DBSA content on the light-to-heat conversion properties of PPy,effects of PPy and DA ratio on light-to-heat conversion performance of PPy@PDA.The results show that when the DBSA is 1:8 and PPy:DA is 1:1,the 1ml/mg PPy@PDA aqueous solution prepared can be increased by 50°C for 10 minutes under the irradiation of 3W/cm~2 near-infrared light(NIR).Adding 5wt%PPy@PDA to the epoxy resin compound,the sample can return to its original shape in a short time,the recovery rate is close to 100%,and the self-repair rate is higher than 98%.Photo-induced shape memory self-healing coatings are prepared by adding PPy@PDA to epoxy resin composites.The effect of PPy@PDA content on the corrosion resistance of coatings are tested by Tafel polarization curve,linear scanning voltammetry curve,and electrochemical impedance measurement.The experiment proves that when PPy@PDA is 5wt%,the anti-corrosion performance and self-repair performance of the coating are best;the narrower the scratch,the better the anti-corrosion performance after self-repair of the coating;the more corrosion products,the lower the coating repair efficiency.