Novel biodegradable form stable phase change materials were obtained in a process involving potato starch gelatulization in water/poly(ethylene oxide) (PEO) solution. DSC and microscopic investigations revealed that the presence of the starch considerably changes PEO phase transition behavior-in the blends solid-solid phase transition for PEO/starch 1 : 3 and 1 : 1 w/w has been observed; for PEO/starch blend 3 : 1 w/w solid-solid phase transition with a partial melting of PEO unbounded through hydrogen bonds with starch has been detected. The heat of phase transition depends on the strength of hydrogen bonds between PEO and starch. The intermolecular interactions were evidenced by FTIR analysis, which showed considerably shift of the stretching vibration bands of both the O-H group (proton-donor group) from starch and PEO. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 116: 1725-1731,2010