Poly(ethylene imine)-graft-poly(ethylene oxide) (PEI-g-PEO) copolymers were synthesized via Michael addition reaction between acryl-terminated poly(ethylene oxide) methyl ether (PEO) and poly(ethylene imine) (PEI). The brush-like copolymers were characterized by means of Fourier transform infrared spectroscopy and nuclear magnetic resonance spectroscopy. It is found that the crystallinity of the PEO side chains in the copolymers remained unaffected by the PEI backbone whereas the crystal structure of PEO side chains was altered to some extent by the PEI backbone. The crystallization behavior of PEO blocks in the copolymers suggests that the bush-shaped copolymers are microphase-separated in the molten state. The PEO side chains of the copolymers were selectively complexed with alpha-cyclodextrin (alpha-CD) to afford hydrophobic side chains (i.e., PEO/alpha-CD inclusion complexes). The X-ray diffraction (XRD) shows that the inclusion complexes (ICs) of the PEO side chains displayed a channel-type crystalline structure. It is identified that the stoichiometry of the inclusion complexation of the PEI-g-PEO with alpha-CD is close to that of the control PEO with alpha-CD. (C) 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 2296-2306, 2008