TECHNOLOGY FOCUS - INORGANIC CHEMISTRY - Preferred Components: The standard electrolytes comprise at least one of iodine, alkali metal and alkaline earth metal iodides (preferably LiI, NaI, KI, CsI, CaI2).    TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Components: The standard electrolytes comprise at least one iodides of quaternary ammonium compounds and of N-heterocyclic cations such as 1,2-dimethyl-3-propyl-imidazolium iodide.    TECHNOLOGY FOCUS - POLYMERS - Preparation (claimed): Preparation of the copolymers (I) involves: the reaction between a copolymer of formula (II) and a monoalkylating halide of formula R2-Hal.Hal=leaving group selected from chloro, bromo or iodo (preferably iodo).Preferred Components: The copolymer (I) has molecular weight of 15000-40000 Da. Preferred Process: The reaction between the copolymer (II) and R2-Hal is carried out in the presence of a solvent and standard electrolytes. In the electrolytes, the iodides are present at a concentration of 0.05-1 M, and the iodine is at a concentration of 0.01-0.3 M. Preferred Definitions:    R1=methyl, butyl or trifluoroethyl;    R2=methyl, n-propyl or trifluoropropyl;    Y-=I-, CF3COO- or (CF3SO2)2N-.    EXAMPLE - Methyl methacrylate (6.70 ml) and 4-vinyl pyridine (0.84 ml) were placed in a flask. AIBN (azobisisobutyronitrile) (64 mg) dissolved in toluene (17 ml) were added to the mixture of monomers de-aerated using a flow of dry nitrogen. The solution was heated under stirring to 65-70 degrees C for 48 hours. After returning the reaction mixture to ambient temperature, the copolymer was precipitated out by pouring the toluene solution slowly into 150-200 ml of methanol which was kept stirred. After work-up 4-vinyl pyridine-methyl methacrylate copolymer (number-average molecular weight of 20800 Da, and weight-average molecular weight of 26300 Da) (A1) (5.6 g) was prepared. The copolymer (A1) (1.8 g) were dissolved in the solvent mixture (5 g) based on 3-methoxypropionitrile/N-methyl oxazolidinone (1/1 wt/wt.). 1,2-Dimethyl-3-propyl imidazolium iodide (0.77 g), iodine (122 mg) and CH3I (0.41 g) were added to the resulting mixture aerated with flow of dry nitrogen. The resulting mixture was kept stirred at 70 degrees C for 20 hours in a nitrogen atmosphere.