FT-IR of membranes made with alginate/polylysine complexes. Variations with the mannuronic or guluronic content of the polysaccharides

FT-IR spectra of polylysine/alginate membranes made with alginate containing various contents of mannuronic or guluronic acid residues have been recorded. The interpretation of the more important absorptions related to functional groups engaged in the complexes have been proposed and discussed using comparisons with spectra of cellulosic films and other published results. Mannuronnic rich alginate seemed to link stronger than guluronic rich alginate to the polylysine molecules which is illustrated by the continuum in absorption between 3000 cm-1 and 2000 cm-1. However, the analysis of the 2000–1000 cm-1 region prompted us to believe that the polymers were engaged in the same basic sort of molecular complexes. Therefore it is necessary that other parameters (either physical, as toughness, porosity, …) other than variations in molecular structures are studied in order that the biological differences of the membranes may be explained.