MACROMOLECULAR FLEXIBILITY AND AGGREGATION TENDENCY OF NON-CROSS-LINKED AND CROSS-LINKED CATIONIC POLYSOAPS

The aggregation tendency of non-cross-linksd and cross-linked poly(alk ylmethyl-diallylammonium halides) bearing n-dodecyl and n-decyl side c hains ((CL)-CopolCl- 12-Cl, (CL)-CopolCl-12-Br and (CL)-CopolCl-10-Br, respectively) in aqueous solution has been evaluated by measuring the ir critical aggregate concentration (CAC). Polysoaps (CL)-CopolCl-12-C l, (CL)-CopolCl-12-Br and (CL)-CopolCl-10-Br all show the same change of their aggregation tendency accompanying an increase in the content of the cross-linking agent. The aggregation tendency of these polysoap s clearly depends upon their macromolecular flexibility that varies in versely with the cross-linking agent content. The decrease of the macr omolecular flexibility that results from an increase in the cross-link ing agent content leads to an increase in the aggregation tendency whi ch reaches a maximum at 0.20% cross-linking agent content. The propens ity for aggregation then decreases with a further decrease of the macr omolecular flexibility. Most strikingly, this conclusion is confirmed by the consistency with catalytic effects of these non-cross-linked an d cross-linked polysoaps on the unimolecular decarboxylation of 6-nitr o-benrisoxazole-3-carboxylate anion (6-NBIC). It is suggested that inc reased aggregation tendency accompanying decreased macromolecular flex ibility for cross-linked polysoaps with a smaller cross-linking agent content should be attributed to an increase of intramolecular miceiliz ation. (C) 1998 Elsevier Science Ltd. All rights reserved.