Modification of track membrane structure by plasma etching

An investigation of the properties of poly(ethylene) terephthalate track membranes (PET TMs) treated with a plasma RF-discharge in air has been performed. The influence of the plasma treatment conditions on the basic properties of the membranes, namely pore size and pore shape, porosity and mechanical strength has been studied. It was arranged that the effect of air plasma on the PET TMs results in etching a membrane's surface layer. The membranes' pore size and the form in this case change. It is shown that it is possible to change the structure of TMs directly by gas-discharge etching. Depending on the choice of discharge parameters, it is possible to achieve etching conditions either in a part of the channel or along the whole length of the pore channels. In both cases membranes with asymmetric pore shapes are formed which possess higher porosity and flow rate. The use of the membranes of such a type allows to increase drastically the efficiency of filtration processes.