salt-polymer interaction in concentrated salt dispersion
Post on 31-Dec-2015
Embed Size (px)
DESCRIPTIONSalt-Polymer Interaction in Concentrated Salt Dispersion. XIAOHUA FANG Columbia University. Center for Particulate & Surfactant Systems (CPaSS) IAB Meeting New York, NY August 20th, 2009. H 2 O. CO 3 2-. Na +. Step III: Understand 3-component systems. - PowerPoint PPT Presentation
Salt-Polymer Interaction in Concentrated Salt Dispersion Center for Particulate & Surfactant Systems (CPaSS)IAB Meeting New York, NYAugust 20th, 2009XIAOHUA FANGColumbia University
Possible Interactions in a Dispersion System
IntroductionChallenges in real formulations containing high salt concentration.Homogenous or dispersed Stable with time or temperaturePourablein a wide range of temperatureLow salt concentration rangecharge screened; polymer collapsed, etc.Ultra-High salt concentration, morphology of polymer chain and its function?The interaction of polyelectrolyte and salt Coil-Collapse-Re-expansion
Materials/Methods*Salt-Polymer InteractionsDensityLight ScatteringConductivityRheometryMaterialsMethods*Sodium carbonate(Soda Ash) *Polyacrylic acid *Water * Other additives*Water related InteractionsWater Activity
Radius of Gyration in concentrated salt solutionRg grows exponentially with salt level increase in entanglement Concentration
Hydrodynamic Radius in salt solutionAt higher salt level, PAA molecules oscillate within a larger effective region.RH increases with polymer concentration after a certain threshold PAA level.
Ion Condensation on PolymersIon condensation happens and the salt species condensed onto PAA chains.
Larger molecules are more effective in holding salts than smaller chains.
Low MwHigh MwSpeculation---Concentration DependenceNo SaltHigh Salt
Higher Salt Level More Rheological Sensitivity to PAA ConcentrationViscosity increases with PAA concentration at all salt levels.At high salt level, the increase in viscosity with PAA concentrationis more significant.
Higher Salt Level More Rheological Sensitivity to TemperatureViscosity decreases with temperature at all salt levels.At high salt level, the decrement in viscosity with temperatureis more significant.
Small MoleculeLarge MoleculeSchematic Diagram of Salt Ions LocalizationLow TemperatureHigh Temperature
Concluding Remarks1.is unfolded and more hydrated. 2.plays a more dominant role on the rheologicalbehavior of the system.3.holds more salt locally. As salt level increases, PAALarger molecules are more efficient in holding ions locally.
Future PlansConduct light scattering, rheological, conductivity measurements on multi-component system.
2.Elucidate the overall mechanism by which dispersion and flow properties are controlled in the system.NSF-Industry/University Cooperative Research Center All the Industrial CollaboratorsWe owe great thanks to: