Effects of charge ratios and cationic polymer nature on polyelectrolyte complex deposition onto cellulose

Sequential addition of poly(diallyldimethylammonium chloride), which is highly cationic, followed by anionic carboxymethylcellulose, has been found to promote inter-fiber bonding during the manufacture of paper, with potential benefits to the recycling of fibers. The present results help to confirm a hypothesis that observed strength gains, in cases where the amount of the first additive exceeded the adsorption capacity of the fibers, were due to the formation of polyclectrolyte complexes in the solution phase, followed by their deposition onto fiber surfaces. Complex formation and retention of complexes on fiber surfaces occurred efficiently over a wide range of polymer charge ratios, cationic polymer attributes, and other conditions, regardless of whether the fibers had been pretreated to reverse their net charge.