Conformational and Experimental Studies on the Dipole Moments of Models of Comblike Polymers

Abstract

The synthesis and radical polymerization of 2,2-bis[4-(2-hydroxyethoxy)phenyl]propyl monoacrylate are described. The values found at 50 and 60 °C for the rate constants ratio, k p/k t 1/2, are similar to those reported for some acrylic polymers with short side groups at the same temperatures although conflicting results are obtained by comparison with the kinetic constants reported for other similar acrylic monomers. The experimental value of the mean-square dipole moment per repeating unit of the resulting polymer, poly{2,2-bis[4-(2-hydroxyethoxy)phenyl]propyl monoacrylate} was 7.24 D2 at 30 °C. This result is very close to the value of 7.83 D2 found, at the same temperature, for the model compound of the side group of the polymer, 2,2-bis[4-(2-hydroxyethoxy)phenyl]propyl monoacetate. Owing to the wide distribution of dipole moments associated with the side groups, the dipolar correlation coefficient of the chains was calculated by combining matricial products of the rotational isomeric state model and Monte Carlo techniques. The calculations suggest that the statistics of long side groups rather than the statistics of the main chain govern the dipolar correlation coefficient of atactic comblike polymers.

Insight into the electrical properties and chain conformation of spherical polyelectrolyte brushes by dielectric spectroscopy

“…Besides the flexible chain conformation, the carboxyl dipoles (or carbonyl dipoles at higher pH) on the PAA chains also contribute to the dipole moment (see red arrows in figure 11). This part of the dipole moment also influence the permittivity ε s or polarity of the brush layer [55][56][57]. As illustrated in figure 11(b), in the soft layer of PS-PAA or PS-PAA-2, the dipoles between carboxyl groups present a disorderly orientation without an apparent dipole moment, while the orientation of the dipoles in the shorter PAA chain layer presents more order (figure 11(a)).…”