Current location: JICS Archive > Vol. 8 > No. 3 > Articles : 22

Influence of Chitosan Grafted Poly(vinyl Sulfonic Acid) as Template on the Calcium Carbonate Crystallization

A. Neira-Carrillo^a,*, P. Mercadé-Jaque^c, M. Diaz-Dosque^b, C. Tapia-Villanueva^c and M. Yazdani-Pedram^c

^aFaculty of Veterinary and Animal Sciences, Universidad de Chile
^bFaculty of Odontology, University of Chile, Santiago, Chile
^cFaculty of Chemical and Pharmaceutical Sciences, University of Chile, Santiago, Chile

     Chitosan was grafted with polyvinylsulfonic acid (CHI-graft-PVS) through either chemical activation (CA) or ultrasound radiation (US) methods and the percentages of grafting (%G), grafting efficiency (%E) and the average degree of polymerization (R) were determined. The effect of CHI-graft-PVS as templates for in vitro crystallization of CaCO₃ was evaluated by using gas diffusion method at different pH. It was found that CHI-graft-PVS act as an efficient modifier of crystal morphology or inhibit the crystallization depending on the experimental media and the method of grafting used. SEM analysis revealed that CHI-graft-PVS obtained through US method act as an inhibitor for CaCO₃ crystallization. When CHI-graft-PVS from CA method was used, SEM analysis showed different CaCO₃ morphologies such as spherical, prismatic, biconcave and needle-like crystals. Additionally, EDS confirmed the presence of S atoms from CHI-graft-PVS adsorbed on the surface of CaCO₃ crystals. Results indicated that CHI-graft-PVS controls the nucleation, polymorphs and morphology of CaCO₃ crystals. The composition of this new template and the control of pH of the mineralization solution seem to be crucial during CaCO₃ crystallization. CHI-graft-PVS template represents an alternative approach for understanding the biomineralization process and offers a wide range of possibility for polymer controlled crystallization.

Keywords: Poly(vinyl sulfonic acid) grafted chitosan, Polymeric template, Gas diffusion method, Crystallization, Calcium carbonate