DETECTION OF A PREFERENTIAL ADSORPTION EFFECT IN THE PNVC CHLOROBENZENE METHANOL SYSTEM BY NMR AND VISCOMETRY

In ternary systems composed by a polymer, a solvent-1, and a solvent-2, where solvent-2 can be nonsolvent for the polymer, it is well known that a preferential adsorption effect is present depending on solvent mixture composition. The authors attention is focused on the system in which a semistiff macromolecule as poly(N-vinylcarbazole) (PNVC) (2) is present. The system studied was formed by PNVC, chlorobenzene (CHLB) as solvent-1, and methanol as solvent-2 (nonsolvent). PNVC was synthesized by cationic polymerization using the (C//6H//5)//3CAsF//6 salt as initiator in dichlorobenzene at 293 K. By dielectric measurements it has been confirmed that PNVC molecules with a weight-average molecular weight lower than 10**5 behave as a rigid rod, while higher-molecular-weight molecules are present as a random coil.