The effect of substitution levels on the luminescent and degradation properties of fluorescent poly(ester-anhydride)s

In this work, two kinds of diacid monomers were synthesized by a convenient scheme, where 4-hydroxy-3-methoxybenzoic acid (vanillic acid) or 4-hydroxy-3,5-dimethoxybenzoic acid (syringic acid) directly condensated with succinic chloride. Corresponding polyanhydrides were obtained by melt polycondensation. Copolyanhydrides composed of the new monomers and sebacic acid (SA) were further prepared and characterized by NMR, DSC, and fluorometer. The two new kinds of polyanhydride emit strong fluorescence and have similar fluorescent spectra to poly(di(p-carboxyphenyl) succinate anhydride) (P(d-CPS)). The emission wavelength (lambda(em)) of the copolymers could be tuned by the excitation wavelength (lambda(ex)). Degradation rate of the copolyanhydrides decreased as dMOCPS or ddMOCPS fraction increased, and the degradation duration could be modulated from several days to more than 3 months. It addition, the copolyanhydrides displayed typical surface-degradation characteristics. (c) 2006 Wiley Periodicals, Inc.