Complex Formation Behavior of Silica Nanoparticles and Xanthan

Abstract

AbstractPolyion complex formation between negatively charged polysaccharide, xanthan, and positively charged silica nanoparticles, Ludox CL is investigated in an acetate buffer at pH 5.0. Appreciable precipitate is found in the composition range cx/cSiNP from 0.056 to 0.58, where cx and cSiNP are the mass concentrations of xanthan and silica nanoparticles, respectively. The sign change of the ζ potential for the mixed solutions is observed in the cx/cSiNP range. Significantly high scattering intensity is detected for the mixed solutions in a wider cx/cSiNP range, clearly showing the complex formation. The scattering profile measured by the small‐angle X‐ray scattering reveals that silica nanoparticles are packed loosely in the complex both when xanthan forms double helix and single chain conformations.