On the salt‐linkage formations of porous and nonporous silica particles with trimethylammonium glycol chitosan iodide

Abstract

AbstractThe stoichiometry of the salt‐linkage formations of nonporous and porous silica particles with trimethylammonium glycol chitosan iodide (TGCI) was investigated by comparing the results of colloid titration and adsorption experiments with those of potentiometric titrations. The surface charge (Q) of colloidal silica as function of pH was evaluated by means of the colloid titration with TGCI. On the other hand, the density (D) of ≡ SiO⊖ groups of silica gel at different pH was also evaluated by the adsorption experiment of TGCI. These results obtained were compared with the Q vs. pH and D vs. pH curves which were obtained by the potentiometric titrations at various ionic strengths for colloidal silica and silica gel, respectively. It was concluded that the ≡ SiO⊖ groups on the surface of nonporous colloid silica form the salt‐linkages stoichiometrically with ⊕N(CH3)3‐groups in TGCI, whereas the salt‐linkage formation between ⊕N(CH3)3‐groups in TGCI and ≡ SiO⊖ groups of silica gel does not follow the stoichiometric relationship, since the salt‐linkages of the ≡ SiOominus; groups in the pores of the silica gel could be affected by the steric hindrance of the TGCI chain.