An amphiphilic polymer containing adenine and aza-crown ethers, poly-{[N,N-bis(2-ethoxy)-1,10-diaza-18-crown-6][5-methylene-(1-adenine)]sophthaloyl ester} (PCASE), was synthesized. The SEM morphology observed indicates that the amphiphilic PCASE polymer self-organized into diameters of about 140～210 nm nanospheres in dilute aqueous solution after recognized with 5-fluorouracil spontaneously. The sizes of PCASE/5-flu nanospheres in dilute aqueous solution determined by dynamic light scattering (DLS) are mainly dispersed at 120～230 nm. The molecule recognition based on hydrogen bond between adenine of polymer and 5-fluorouracil substrate in PCASE/5-flu nanospheres was studied. After recognition the C(2)＝O stretching vibration at 1724 cm^-1 of 5-fluorouracil subtract shifted to 1718 cm^-1, the NH₂ stretching vibration at 3324 cm^-1 disappeared, and a new peak at 3432 cm^-1 arised, indicating the formation of hydrogen bonds between 5-fluorouracil and adenine in polymer PCASE．The study on variable temperature FTIR show that the peak 1718 cm^-1 gradually shifted back to the position at 1724 cm^-1, and the new peak 3432 cm^-1 disappeared finally, indicating that the H-bond was broken.

Key words: amphiphilic polymer, aza-crown ether, self-organization, molecular recognition