Study On Interfacial Adhesion And Electrode Properties Of Polyester/polypyrrole Conductive Composite Films

The conductive polymer,polypyrrole,can be applied to the polyester film by coating it on the surface of polyester film.The conductive composite film can be used in many fields such as the electrode of flexible supercapacitor.But the surface of polyester film is smooth and has few polar groups.Its surface free energy is low and wetting and adhesion properties are poor.The adhesion of polypyrrole layer to the film surface is weak.The polypyrrole layer is easy to fall off.So the surface of the PET film needs to be pre-modified to enhance the interfacial adhesion of the polyester/polypyrrole conductive composite film and to improve the capacitance performance of the composite film electrode.The effect of different plasma treatment time on the surface properties of polyester film and the interfacial adhesion of polyester/polypyrrole composite film was studied by plasma treatment.The results showed that the oxygen plasma pretreatment can increase the surface roughness,the content of the surface polar oxygen-containing functional groups(mainly C-O)and the surface electronegativity of the polyester film,thus significantly improving the interfacial adhesion of polyester/polypyrrole composite film.The increase of surface roughness and surface electronegativity is the main reason for the enhancement of interfacial adhesion.The effects of plasma treatment time on the grafting ratio and surface properties of polyester films and the interfacial adhesion of polyester/polypyrrole composite films were investigated by plasma-induced vapor phase graft polymerization of acrylic acid.The results showed that when the plasma treatment time was 500s,the grafting ratio of PET film was the highest,and the wettability and the reactivity were the best,and the adhesion of polypyrrole to the film surface was the strongest.The-NH group of PPy forms a strong hydrogen bond with the-COOH group on the surface of the film.The supercapacitors were respectively fabricated with the control-PET-PPy composite film,p-PET-PPy composite film and g-PET-PPy composite film as the electrodes.The results showed that plasma-induced vapor phase graft polymerization of acrylic acid had better effect on the capacitance performance of PET/PPy composite film electrode than that of plasma treatment.