MODIFICATION OF TRACK MEMBRANE-STRUCTURE BY PLASMA-ETCHING

An investigation of the properties of poly(ethylene) terephthalate tra ck membranes (PET TMs) treated with a plasma RF-discharge in air has b een performed. The influence of the plasma treatment conditions on the basic properties of the membranes, namely pore size and pore shape, p orosity 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 c hange. It is shown that it is possible to change the structure of TMs directly by gas-discharge etching, Depending on the choice of discharg e parameters, it is possible to achieve etching conditions either in a part of the channel or along the whole length of the pore channels. I n both cases membranes with asymmetric pore shapes are formed which po ssess higher porosity and flow rate, The use of the membranes of such a type allows to increase drastically the efficiency of filtration pro cesses. (C) 1998 Elsevier Science B.V. All rights reserved.