Influence of Temperature on the Conformational Guided Physical Properties of Ultrathin Films of PLLA

Abstract

Poly (L lactic acid) (PLLA) ultrathin films of various thicknesses were prepared by spin coating method and investigated by using vibrational spectroscopic techniques such as FTIR and Raman. The analysis has been done in two parts: first one is verification of structural mode to understand the visibility of characteristic band to confirm the PLLA structure; where interestingly, as the thickness of the film increased, the structural features were found to be more explicit. The second part of the study was to observe the features of the film having been annealed for 1 h in two separate temperatures, one at specific annealing temperature 120 °C and the other at 160 °C to enable PLLA chains to reorient to get crystallized from its soften state at two such specific temperatures. The isothermal crystallization behavior of PLLA film at 120 °C and 160 °C from the melt was monitored by FTIR as well as Raman spectroscopies. More importantly, the band at 921 cm -1 corresponds to α crystalline phase of PLLA has been observed even in this ultrathin film with the effective application of temperature as selected in this study.

Microstructural and optical properties of polyvinyl alcohol/manganese chloride composite film

“…The shift and broadening of the peak can be attributed to the formation of complex between PVA and manganese chloride. The interactions between manganese dichloride and PVA are distributive in nature depending upon the accessibility of the in-situ active sites in the conformational structure [9] of the polymer chain and manganese chloride in the vicinity for interaction. In recent past we developed nanocomposite systems like PVA/Co, PVA/Co/C, and PVA/Co/Ag by sputtering nanoparticles of cobalt, carbon, and silver on PVA film where we found XRD peak in all such PVA/Co, PVA/Co/C, and PVA/Co/Ag systems [6][7][8] in the same position at 2θ = 19.81 as in the present pristine PVA film.…”

“…The shift and broadening of the peak can be attributed to the formation of complex between PVA and manganese chloride. The interactions between manganese dichloride and PVA are distributive in nature depending upon the accessibility of the in‐situ active sites in the conformational structure of the polymer chain and manganese chloride in the vicinity for interaction.…”

“…It is a nice matrix material to accept metal nanoparticles to display magnetic properties [7,8]. One of the important advantages of PVA as optical material may be due to its amenability to facile fabrication of optical devices like planar optical waveguides [9] and optical image storage system [10][11][12].…”