A simple strategy to increase the interfacial adhesion between TiO2 nanotube layer and Ti substrate

The weak interfacial adhesion between the anodic TiO2 nanotube array (TNTA) layer and Ti substrate results in the difficulty of the subsequent applications. Here, we report an efficient strategy to enhance the adhesion of the TNTA layer to the Ti substrate. That is, after completion of the fabrication of TNTAs, anodization was further performed at 10 V for 5 min in the same electrolyte. The sample subjected to the lower voltage anodization posttreatment shows 1.5 times improvement in interfacial adhesion compared to the one without posttreatment. The enhanced interfacial adhesion can be ascribed to elimination of the residual stress at the interface. Moreover, the lower voltage posttreatment can also achieve a 45.8% increase in areal capacitance of TNTAs, which can be attributed to the increased contact area between the TNTA layer and Ti substrate.