Influence of Crystallization on Molecular Dynamics of the Amorphous Phase in Poly(ε-caprolactone) and Poly(ε-caprolactone)/LiClO4 Complexes Investigated by Dielectric Relaxation Spectroscopy

The dielectric relaxation spectroscopy results indicate that the relaxation peak of PCL for pure PCL and PCL/LiClO4 complexes shifts to a lower frequency with increasing crystallization temperature, while the amorphous, condensed structure of PCL for pure PCL and PCL/LiClO4 complexes is slightly affected by crystallization temperature. These findings were obtained from small-angle X-ray scattering (SAXS) measurements. To further understand the effect of crystallization temperature on the relaxation behavior of PCL and PCL/LiClO4 complexes, the isothermal crystallization process of PCL and PCL/LiClO4 was probed in situ by dielectric spectra measurement. The analysis indicated that the relaxation dynamics for pure PCL and PCL/LiClO4 complexes decrease continuously during the isothermal crystallization process, even at the crystallization induction period. This paper presents a detailed discussion of the crystallization mechanisms of the PCL and PCL/LiClO4 complexes, and the probable explanation as to the effect of crystallization temperature on the relaxation dynamics of PCL and PCL/LiClO4 .