Crosslinked Chitosan Films Research Articles

The cooperative binding behavior of sodium dodecyl sulfate to crosslinked chitosan films

The binding behavior of sodium dodecyl sulfate (SDS) to cationic chitosan, in the form of a swollen crosslinked film is described. Chitosan films were crosslinked with epichlorohydrin. Binding isotherms were determined potentiometrically. The binding isotherms of the crosslinked chitosan was compared to the binding isotherms of chitosan in free solution. As expected, a more highly cooperative binding phenomena is observed, than for cationic chitosan in free solution. The collapse of the gel occurs at a binding fraction greater than 0.6. The collapsed cationic chitosan/SDS complex is described. The presence of hydrophobic regions within the chitosan-SDS complex was demonstrated with the oleophilic dyes C.I. Disperse Yellow 23 and C.I. Solvent Green 3. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 3755–3765, 1997

Preparation and antibacterial activities of crosslinked chitosan films.

Five kinds of chitosan films were prepared in order to study the antibacterial activities against E. coli and St. aureus. Film (1) was prepared by casting of an acetic acid salt of chitosan solution. Films (3) were prepared from film (1) by swelling treatment with aqueous NaOH solutions, and subsequent crosslinking with epichlorohydrin at 85°C for 2 h. Films (4) were prepared from films (3) by treating with a 5% aqueous acetic acid solution. Films (2) and (5) were prepared from film (1) and films (4) by treating with aqueous NaOH solutions, respectively. Film (1) and films (4) indicated antibacterial activities against E. coli and St. aureus. However, films (2), (3) and (5) did not show any antibacterial activities. Film (1) showed a higher antibacterial activity against E. coli and St. aureus than films (4). These results suggest that the antibacterial activities of the films (1) and (4) are dependent on their abilities of the formation of acetic acid salt and also on their structures of acetic acid salt. By the treatment with an aqueous acetic acid solution, the antibacterial activities of films (4) were revealed without a remarkable decrease in the activity after several cyclic treatments with an aqueous NaOH solution and with an aqueous acetic acid solution.