Controlled change of transport properties of poly(ethylene terephthalate) track membranes by plasma method

Modification of polymer membrane properties by low-temperature plasma

“…4). Hydrophilic composite membranes with a high surface concentration of COOH groups were produced by the deposition of plasmapolymerized acrylic acid films [71][72][73][74][75][76][77][78][79][80]. The wettability of the membrane surface is therewith much enhanced and, moreover, the modified membranes show high cation-exchange capacity and separation selectivity.…”

“…It was shown that the film formed by plasma polymerization of dimethylaniline on the membrane surface can swell in solutions with low pH values [74,93]. This process is induced by protonation of nitrogen atoms, as a result of which molecular units of the plasma-deposited polymer film acquire a positive charge and capacity to swell, forming a polyelectrolyte gel [100] and thereby decreasing membrane pore diameter.…”

“…In this case, the polymer film that forms swells in solutions with high рН values [73,74]. Therefore, the composite membrane by a plasma-polymerized acrylic acid film has a low water permeability in an alkaline medium.…”

“…Composite membranes with unique properties were also obtained on the basis of PET TM by polymer film deposition in aniline [101,102], thiophene [103][104][105], and pyrrole plasmas [105][106][107]. A characteristic feature of such membranes is that they have two layers ( Fig.…”

“…For example, mechanochemical membranes having a "chemical valve" function were obtained by grafting poly(acrylic acid) [74] and poly(2-methyl-5-vinylpyridine) [120] onto the surface of PET TM pretreated by an air plasma. Thus, the membrane with the poly(2-methyl-5-vinylpyridine) grafting yield of 7.2% at рН = 3 can change over to the "chemical valve" operating mode, specifically, at low pHs of the filtrate it becomes waterimpermeable, whereas at higher pH values it is waterpermeable (Fig.…”