Polyelectrolyte complex beads of carboxymethylcellulose and chitosan: The controlled formation and improved properties

Spherical beads made of naturally derived polymers can be widely used as a promising matrix in many biorelated and safety required fields. Herein, the optimal parameters for fabrication of a core-shell bead composed of carboxymethylcellulose (CMC) and chitosan (CHI) are established based on systematic investigations on working distance, solution pH and polymer concentrations. Spherical beads will be obtained when the working distance is set as 15 cm. The beads prepared at pH 4.5 are the strongest and can resist to a force of up to 0.071 N. It will be shown that the critical concentration of polymer solutions plays important roles in determining the shape and size of beads. The observation of two new peaks at 1723 cm(-1) and 1592 cm(-1) in the FTIR of the prepared beads demonstrate the electrostatic interactions between CMC and CHI. With a post gentle heating (35 degrees C), the stability of beads is significantly improved and the swelling degree in water increases to 220%.