Controllable modification of polymer membranes by long-distance and dynamic low-temperature plasma flow: Long-distance and dynamic characteristics

The long-distance and dynamic characteristics of low-temperature plasma in a state of flow were studied by observing the glow distance of plasma and detecting the peroxide content formed on the polymer membrane after irradiation. The field emission scanning electron microscopy and accurate weight loss analysis were respectively employed to observe the decreased etching effect of long-distance plasma on uniaxially stretched poly(tetrafluoroethylene) membranes. The effects of plasma excitation time, plasma power, gas flowrate and chamber pressure on the peroxide contents were investigated using polypropylene fiber membranes. The dynamic characteristic of plasma was furthermore discussed by exploring the penetration of plasma flow through membrane pores. The dynamic plasma flow not only exhibited a longer glow distance than static plasma, but also can obtain greater peroxide contents, and even still can penetrate the first membrane and further treat the second membrane layer. The etching and degradation effects of membrane can be significantly reduced in a long-distance and dynamic lowtemperature plasma (LDDLTP) flow. The safe distance to minimize the plasma damage to the membrane depends greatly on the plasma conditions. The long-distance acts and complete penetration performances of LDDLTP we have achieved could provide valuable references for membrane modifications in more flexible forms.