Improving the delamination resistance of indium tin oxide (ITO) coatings on polymeric substrates by O2 plasma surface treatment

This work presents the effect of O2 plasma surface treatment of polymeric substrates on improving the mechanical reliability; particularly, the buckling delamination resistance of ITO coating on the substrates. ITO of various thicknesses is sputter-deposited and the delamination resistance is evaluated by uniaxial tension test. The strain at initiation of the buckling delamination (εbi) due to Poisson’s contraction perpendicular to the direction of tension is used as a metric of the resistance. The test results show that εbi of ITO on treated substrate is significantly increased compared to ITO on bare PET at all thicknesses. According to contact angle measurement and X-ray photoelectron spectroscopy (XPS) analysis, O2 plasma treatment increases the surface energy of PET by increasing oxygen-containing polar groups on the surface, which seems to improve the adhesion strength between ITO and PET and to make ITO more resistance to compression.