Dipolar microstructure is a property
related to the orientation
of dipole moments along a polymer chain, which is dependent on how
asymmetric monomers are oriented (i.e., regio-order). The control
over the dipolar microstructure offers the possibility to monitor
single-chain behavior in an electric field thus providing important
structural and dynamical information. Using broadband dielectric spectroscopy
(BDS), in this study, we first demonstrate that the initiation of
glycidyl phenyl ether with the t-BuP4 phosphazene
base and water leads to the formation of a polyether composed of two
symmetric regioregular subchains with an opposite dipole moment orientation.
After modification of hydroxyl end groups into alkyne, macrocyclic
poly(glycidyl phenyl ether)s with an inverted-dipole microstructure
were synthesized via Glaser coupling. The macrocycles obtained using
this strategy display a dielectric normal mode relaxation that specifically
reflects the fluctuations of the ring diameter. This important characteristic
allowed us to evaluate the macrocyclic chain dynamics by BDS resulting
in a dipole relaxation of the ring diameter 1.6 times slower compared
to the analogous relaxation in the inverted-dipole linear precursor.
These results highlight two main points, the power of BDS in the verification
of architectural features of polymers having a net dipole moment component
along the chain contour, and the potential of inverted-dipole macrocycles
in the study of fundamental physical problems in polymer rings.