LOCAL INTRAMOLECULAR MOBILITY AND CONFORM ATIONAL PROPERTIES OF COMB-SHAPED POLYMERS - EFFECTS DUE TO SIDE-CHAIN AGGREGATION

Dipole polarization relaxation and the dipole moments of the cholester ol ester of poly(methacryloyl-omega-oxyundecanoic acid) in dilute tolu ene and decane solutions were examined. The dielectric loss factor sho wed three regions of dielectric absorption in the temperature-frequenc y plots: two of the relaxation processes involve local motions and are related to partial mobility of the two ester groups, whereas the thir d is a large-scale process, characterized by large relaxation times, a nd it reflects the mobility of the ester groups linked to the stacked cholesterol fragments. In solvents of poor thermodynamic quality, the dipole moment and the relaxation time of one of the local relaxation p rocesses related to the mobility of the main chain revealed abnormal t emperature-dependent behavior (intramolecular conformational transitio n). The conformational rearrangements and the decrease in local mobili ty of the main chain are interrelated and are due to the greater tende ncy of the side chains to aggregate.