Poly-(l)-lactic acid (PLLA) was solvolyzed with polyethylene glycol (PEG) with different ratios of PLLA and PEG under dry conditions. The obtained materials were found to be the block copolymer of PLLA and PEG (PLLA/PEG) from NMR analysis of which the number average molecular weights ranged from 6 × 103 to 2 × 104 g mol−1. The films of stereocomplex (SC) of PLLA/PEG and poly-(d)-lactic acid (PDLA) were prepared by solvent casting method, and the thermal properties and the contact angle of the films were examined. The melting temperatures of PLLA/PEG and the corresponding SC with PDLA linearly decreased with the increase in the PEG content from 110 to 170 °C. The contact angle of PLLA/PEG became lower when the PEG content in the PLLA/PEG was higher, while their SCs with PDLA showed no clear correlation with the PEG content. Biodegradability of PLLA/PEGs and their SCs were also investigated with respect to the EG content.

An X-ray absorption fine structure (XAFS) study has been conducted to reveal the local structure and chemical state of the copper in the complex of an acetylacetonate-based ligand (L1) and copper ion in acetonitrile solution. The copper ion in the complex was found to be divalent from the Cu K-edge X-ray absorption near-edge structure (XANES) spectrum. The FEFF (ab initio multiple scattering calculations of XAFS) were performed with the model compounds, whose structures were optimized by using MOPAC program with AM1 Hamiltonian. The comparative study of the experimental XAFS spectra and theoretical calculations from FEFF gave the perspectives for clarifying the coordination structure of the complex of L1 and copper ion.