POLYELECTROLYTES OF HIGH CHARGE-DENSITY IN ORGANIC-SOLVENTS - SYNTHESIS AND VISCOSIMETRIC BEHAVIOR

An easy anion exchange between electrolyte monomers of the quaternary ammonium halide type such as [(2-methacryloyloxy)ethyl]trimethylammoni um chloride or 1-vinyl-3-methylimidazolium iodide and various cyanocar bon salts such as 1,2,2-tricyanoethenolate, 1,1,2,3,3-pentacyanopropen ide, alpha,alpha-dicyano-p-toluoylcyanide, or p-(tricyanovinyl)phenyld icyanomethide readily leads to a series of new hydrophobic electrolyte monomers with yields generally over 70%. [(2-Methacryloyloxy)ethyl]tr imethylammonium 1,1,2,3,3-pentacyanopropenide is a most representative example. its free radical polymerization in homogeneous solution (DMF , 60 degrees C) currently yields atactic chains (Bernoulli stereopropa gation process, probability of meso placement P-m = 0.31) of fairly hi gh degree of polymerization (DPw similar to 1600) which show an unique spectrum of solubility in dipolar organic solvents (dipole moment mu > 2.6 D) covering a very broad range of dielectric constants (epsilon similar to 10-180). Viscosity measurements performed in 13 solvents al low us to analyze the polymer solution properties in three different s ituations: (a) For good, but weakly dissociating solvent (triethyl pho sphate, epsilon similar to 10), there were no polyelectrolyte effects. (b) For good and fairly to highly dissociating solvents (cyclopentano ne...2-cyanopyridine, epsilon similar to 13-90), as a general trend, p olyelectrolyte effects increase with the dielectric constant, but the usual excluded volume effects remain a factor of the number of effecti ve charges per chain, as estimated from the ratio A/B of the parameter s of the Fuoss equation in its simplified form (eta(red) = A/1 + BC0.5 ). (c) For very poor but very strongly dissociating solvents (formamid e, N-methylformamide, epsilon > 100), there were no polyelectrolyte ef fects at 25 degrees C and transition to a fairly good solvent at about 50 degrees C with simultaneous emergence of weak polyelectrolyte effe cts. These new hydrophobic polyelectrolytes appear as optimized and ve rsatile models for the quantitative analysis of the influence of the u sual excluded volume effects and of the specific electrostatic interac tions on the static and dynamic solution properties of polyelectrolyte s in all possible solvation and dissociation situations.