Abstract: Association of polyoxyethylene n-octylphenol ether(OP) with β-cyclodextrin(β-CD) was investigated using OP as a fluorescent probe. The results show that the n-octyl with phenyl ring was entrapped into the cavity of β-CD. 1-bromo-naphthaline (BN) was further employed as a phosphorescent probe to monitor the binding site of OP and the spatial effect of OP on BN. The n-octyl chain of OP was located in the cavity of β-CD in a compressed manner. As a result, the binding strength of BN to the β-CD cavity occupied by OP decreases due to the geometric considerations.

Key words: β-cyclodextrin, Polyoxyethylene n-octylphenol ether, Nonionic surfactant, Fluorescence, Phosphorescence