Fabrication of alginate/chitosan complex fibers via diffusion controlled in-situ polyelectrolyte complexation

Alginate (ALG) and chitosan (CHI) are naturally occurring polymers, and present broad applications in various fields. Owing to the electrostatic interactions between the two polymers, ALG and CHI are combined to prepare fibers via diffusion controlled in-situ polyelectrolyte complexation. A map of the concentration combination of spinning and coagulation solution is presented for the fabrication of the complex fibers. When concentration combination meets the requirements for fiber formation, increasing the concentration of the spinning or coagulation solution will slow down the diffusion, which will affect the composition and mechanical properties of the prepared fibers. Prolonging complexation time or increasing temperature will enhance the diffusion, and more polyelectrolytes with opposite charged-groups will be taken from the coagulation solution, hence the fibers modulus will increase. In addition, the fiber composition and initial modulus are found to be correlated, and the inner structure of the fiber is revealed using the fluorescence imaging technique.