Complex Coacervation of Hydrophobically Modified Gelatin and Poly(ethyleneimine)

초록

Complex coacervations of hydrophobically modified gelatin and poly(ethyleneimine) (PEI) were extensively investigated by a light scattering method. Decanoyl gelatin (DeGel) and decanoyl PEI (DePEI) were prepared by condensation reactions between the carbonyl chloride of decanoyl chloride and the amino groups of the polymers. The chemical modification was confirmed by H-1 NMR and FT-IR spectroscopy. DeGel and DePEI were found to be surface-active by surface tension measurements. At pH 7.0 the hydrodynamic diameter of DeGel/DePEI complexes and the light scattering intensity of the complex suspensions were maximum when the molar ratio of the carboxylic groups of DeGel to the amino groups of DePEI was 5/5. At the ratio of 5/5 the hydrodynamic diameter was maximum when the pH value of the medium was 7.0. Since the diameter and the light scattering are measures of complex coacervation, it was concluded that the complex coacervation took place maximally when the ratio was 5/5 and the pH value was 7.0.

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