Optical properties and chemical structures of Kapton-H film after proton irradiation by immersion in a hydrogen plasma

► Proton irradiation on polyimide films is conducted by immersing the samples in hydrogen plasma. ► The spectral transmittance decreases in the wavelength of 500-2000 nm after proton irradiation. ► Surface etching and the polymer chains breakage make finger-like bulges emerge in the surface of the sample. ► The content of C element increases, while that of N and O elements decreased after proton irradiation.