A hot drawing process has been applied to improve the physical and the mechanical properties of polylactide nanocomposite films through the self-reinforcement of molecular structure. The structural evolution led to development of a mesomorphic molecular ordering during the stretching process. This was attributed to the predominant impact of the chain extension rate compared to relaxation rate, along with the influence of thermodynamic structural parameters. The mesophase is reflected in WAXS pattern by a diffraction peak associated with a repeated arrangement of segments, normal to the chain axis, with an intermediate lateral chain packing between the crystalline structure and the amorphous phase. The fraction of mesophase decreases with the nanoparticle content. This was interpreted by the enhanced contribution of matrix relaxation compared to deformation rate, at the stretching rate and the temperature, upon the incorporation of the nanoparticles due to the accelerated matrix degradation with the nanoparticle loading. The yield stress is enhanced in subsequent stretching process of the hot-drawn films at room temperature owing to the oriented microstructure, lied in the mesomorphic domain. Furthermore, with the development of mesophase in hot-drawn film, the strain hardening behavior was detected in the subsequent drawing at room temperature. Then, the strain hardening occurs at a critical mesophase content since the mesomorphic domain act as physical junction. In this study, permeability was divided into diffusivity and solubility coefficients. The diffusivity decreased with the mesophase content in the hot drawn films. This was concluded that the synergistic influences of the presence of mesomorphic domain and the incorporation of the nanoparticles, in the absence of network structure, cause a considerable decrease of the diffusivity and the permeability of the hot-drawn films. The solubility was increased with the increase of nanoparticles content.