Polyelectrolyte Multilayers from Cationic and Anionic Starch: Influence of Charge Density and Salt Concentration on the Properties of the Adsorbed Layers
العنوان: | Polyelectrolyte Multilayers from Cationic and Anionic Starch: Influence of Charge Density and Salt Concentration on the Properties of the Adsorbed Layers |
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المؤلفون: | Lundström-Hämälä, Lisa, Johansson, Erik, Wågberg, Lars |
المصدر: | Starke (Weinheim). 62(2):102-114 |
مصطلحات موضوعية: | Model surfaces, Polyelectrolyte multilayer, Stagnation point adsorption, reflectometry, Starch, Quartz crystal microbalance, paper strength properties, wood fibers, adhesive properties, ionic-strength, adsorption, size, flow, TECHNOLOGY, Chemical engineering, Chemical process and manufacturing engineering, Cellulose and paper engineering, TEKNIKVETENSKAP, Kemiteknik, Kemisk process- och produktionsteknik, Cellulosa- och pappersteknik |
الوصف: | The purpose of the present work was for identify limits for the formation of stable polyelectrolyte multilayers (PEMs) from cationic and anionic starches (with degrees of substitution of 0.04-0.09) on SiO2 surfaces, taking account of the effect of the charge density of the starches and the salt concentration in the surrounding water phase. The experiments were performed at a pH of 6.3 using stagnation point adsorption reflectometry (SPAR) and quartz crystal microbalance with dissipation (QCM-D). From these experiments it was concluded that it is possible to form PEMs by the adsorption of oppositely charged starches on SiO2 surfaces; it was also found that adsorption of the first layer is controlled both by electrostatic, non-ionic interactions and by pure steric restrictions, Le, geometrical restrictions, at the surface. The results also indicate that the charge density of the starch must exceed a certain value to allow multilayer formation and that this critical charge density increases with increasing salt concentration. The combination of charge densities of the cationic/anionic starches was also found to influence the adsorption behaviour, and the formed polyelectrolyte multilayers had a high water content of 69-92%. |
وصف الملف: | |
الوصول الحر: | https://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-19287Test |
قاعدة البيانات: | SwePub |
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