Direct Force Measurements between Cellulose Surfaces and Colloidal Silica Particles

Article Article scientifique Article Direct Force Measurements between Cellulose Surfaces and Colloidal Silica Particles eng 2005 author Radtchenko Igor 585389 author Papastavrou Georg Alexander 553547 author Borkovec Michal 134121 3057-3066 10.1021/bm050371d 1525-7797 https://pubs.acs.org/doi/10.1021/bm050371d The interaction of cellulose layers with colloidal silica particles was investigated by direct force measurements with the atomic force microscope (AFM). Upon approach, repulsive forces were found between the negatively charged silica particles and the cellulose surface. The forces were interpreted quantitatively in terms of electrostatic interactions due to overlap of diffuse layers originating from negatively charged carboxylic groups on the cellulose surface. The diffuse layer charge density of cellulose was estimated to be 0.80 mC/m2 at pH 9.5 and 0.21 mC/m2 at pH 4. The forces upon retraction are characterized by molecular adhesion events, whereby individual cellulose chains desorb from the probe surface. The retraction profiles are dominated by well-defined force plateaus, which correspond to single-chain desorption forces of 35−42 pN. We surmise that adsorption of cellulose to probe surfaces is dominated by nonelectrostatic forces, probably originating from hydrogen bonding. Electrostatic contributions to desorption force could be detected only at high pH, where the silica surface is highly charged. Dewey 540 40 Département de chimie minérale, analytique et appliquée 145 false Biomacromolecules 6 6 4dda82f9-e6e7-4827-a52b-695a33bcb526 Article (Published version) Restricted Direct_MB_2005.pdf 731515 application/pdf restrictedAccess Faculté des sciences / Section de chimie et biochimie / Département de chimie minérale, analytique et appliquée

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Direct Force Measurements between Cellulose Surfaces and Colloidal Silica Particles	Biomacromolecules			2005	217	0

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Radtchenko, Igor