The effect of CuCl2 on the conformation at changes and crystallization behavior of PEG was studied by using FT-IR, DSC and WAXD. The Cu2＋ and the oxygen atoms of PEG molecular chain have formed coordination bond. By an electrical conductivity method it was found that one Cu2＋ and three PEG chain units formed one coordination structure, which caused the change of conformation and crystallization behavior of PEG. With the increase of the content of CuCl2 in the complexes, the amount of the gauche conformation relative to the trans conformation of PEG crystal increased. When the content of the CuCl2 was about 7% (w), the gauche conformation reached maximum. When the content of the CuCl2 was about 9% (w), the amount of the trans conformation relative to the gauche conformation of PEG crystal increased. With the increase of the content of CuCl2, the crystallinity of PEG in the complexes decreased. When the content of CuCl2 was about 9% (w), the crystallinity increased again.

Key words: CuCl2, polyethylene glycol (PEG), coordination structure, conformation, crystallization