| 个人简介 | |
|---|---|
 Prof. Lee D. Wilson University of Saskatchewan, Canada |
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| 标题： Hydration and Adsorption Phenomena of Biopolymers in Heterogeneous Solid-Liquid Systems | |
| 摘要： Molecular selective adsorption processes at the solid surface of biopolymers in mixed solvent systems are poorly understood due to manifold interactions. However, the ability to achieve adsorptive fractionation of liquid mixtures is posited to relate to role of specific solid-liquid interactions at the adsorbent interface. The hydration of solid biopolymers (starch, cellulose, etc.) in binary aqueous systems is partly governed by the relative solvent binding affinities with the biopolymer surface sites, in accordance with the role of textural and surface chemical properties. While molecular models that account for surface area and solvent effects provide reliable estimates of hydration energy and binding affinity parameters, spectroscopic and thermodynamic methods offer a facile alternative experimental approach to account for detailed aspects of solvation phenomena at biopolymer interfaces during adsorption. In this presentation, thermal and spectroscopic methods were used to gain insight on the interaction of starch- and cellulose-based materials in neat and binary water-ethanol (W-E) mixtures. Batch adsorption studies in binary W-E mixtures reveal the selective solvent uptake properties by the biomaterials, in agreement with their solvent swelling in pure water or ethanol. The nature, stability of the bound water and the thermodynamic properties of the biopolymers in variable hydration states were probed via differential scanning calorimetry (DSC) and Raman spectroscopy. The trends in biopolymer-solvent interactions are supported by dye adsorption and scanning electron microscopy (SEM) results, further indicating that biopolymer adsorption properties in W-E mixtures strongly depend on the surface area, pore structure, and accessibility of the polar surface groups of the biopolymer systems, in line with solvent selective uptake results reported herein. | |
| 简介： Self-assembled biopolymer composites were prepared that contain chitosan with enhanced surface area and variable morphology. Spectroscopic (FTIR, UV-vis, and 13C solids NMR)results provide supporting evidence for the self-assembly of chitosan and a second component polymer.Thermal analysis,XRD and SEM provide support that unique composites are formed that differ from physical mixtures. Unique surface chemical properties of the composites are shown by equilibrium swelling,nitrogen gas uptake, and dye-based adsorption studies. Batch equilibrium and one pot dynamic sorption studies with dye probes (cationic/ anionic)illustrate that the uptake properties of the composites are highly variable.Self-assembly of multi-component systems reveal that the composites possess enhanced surface area, variable site accessibility of functional groups, and variable morphology.The structure-function properties of such biopolymer composites display tunable surface properties according to their variable hydrophile-lipophile balance. The unique structure-function properties of the composite systems differ uniquely from single component systems, and reveal the promising potential for advanced technological applications in water treatment, nano medicine and drug delivery. | |
