CHARACTERISTIC RATIO OF THE MEAN-SQUARE END-TO-END DISTANCE OF POLY(VINYLIDENE FLUORIDE) WITH MICROSTRUCTURAL DEFECTS

The segment length distribution of isoregic head-to-head and tail-to-tail sequences in poly(vinylidene fluoride) (PVF2) chains is calculated from F-19 NMR literature data. It is found that the average length of inverse segments is very close to one unit; therefore almost all head-to-head defects are immediately repaired by an adjacent tail-to-tail addition. The role of microstructure on the characteristic ratio of the end-to-end distance is then investigated. Results obtained by two different methods indicate that, in agreement with previous Monte Carlo calculations, defects play a minor role for the conformational characteristics of PVF2. However, a slight contraction of about 4% is expected for very defective chains.