Abstract: The surfaces of polyethylene(PE) membrane,a good separator material in Li-ion battery,were modified with low temperature HMDSO/O₂/Ar plasma,generated by atmospheric pressure coplanar dielectric barrier discharge(CDBD) actuator.The microstructures and properties of the modified PE surfaces were characterized with scanning electron microscopy,attenuated total reflection Fourier transform infrared spectroscopy,X-ray photoelectron spectroscopy,water contact-angle and thermal shrinkage measurements.The results show that the plasma irradiation matters.Specifically,irradiated by the short period low power plasma,the layer of flocculent SiO_xC_yH_z nano-particle coexisted with the randomly distributed radicals,including the Si(CH₃)_x,Si-OH,COOH and C-OH groups,on the highly porous fiber network of PE-substrate,resulting in a significant improvement of the wettability and thermal resistance.For example,the PE surfaces had the lowest thermal surface shrinkage ratio of 0.5% and a water contact angle of 24.4°.