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theses

The blending of macromolecules such as proteins with polysaccharides has many applications in the medical and environmental sectors, such as scaffolding for tissue engineering and as water filtration membranes for the removal of heavy metals. However, our inability to predict the relationship between molecular interactions and spatiotemporal structures is preventing their rapid utilization and commercialization. Up-to-date, we have learned the importance of appropriate hierarchical and secondary structures upon material dissolution and regeneration, and its effect on the physicochemical properties. However, much more knowledge is required to fully understand molecular self-assembly behavior and spatiotemporal morphology in blended systems to attempt to define and characterize the basic phenomenon and mechanisms to control the cell-biomaterial interactions or remediation efficiencies. In this work, we focused on understanding the association behavior of protein in the presence of polysaccharide and the effect of acetamido and amine groups on the structure with the utilization of ionic liquid solvents. In the first study, the ionic liquid 1-allyl-3-methylimidazolium chloride (AMIMCl) was used to dissolve individual polysaccharides (e.g. cellulose, chitin, and chitosan) with protein (e.g. silk). Water is used as the coagulating agent. The upper and lower proportions of silk were used to test the crystallinity of the beta sheet and to understand how the functional groups of each polysaccharide may interact differentially with increasing silk concentrations. The various blended polymers were characterized using Attenuated Total Reflectance Fourier Transform Infrared spectroscopy (ATR-FTIR), Thermogravimetric Analysis (TGA), Differential Scanning Calorimetry (DSC) and Scanning Electron Microscope (SEM) techniques. The results showed that increasing the silk content in the polysaccharides can increase the molecular interactions between the biopolymers, causing an increase in the stability of the blended film; especially, the formation of beta sheets. The second study investigated the effects of different ionic liquids 1-allyl-3-methylimidazoliumchloride(AMIMCl), 1-ethyl-3-methylimidazoliumchloride (EMIMCl) and 1-ethyl-3-methylimidazolium acetate (EMIMAc) on the structural modification, thermal stability and topology of blended films comprised of chitin with silk. Similarly, the third study investigated the effect of AMIMCl and EMIMCl on the structural changes and thermal properties of blended film comprised of chitosan with silk. We observed the modification of the structural, morphological, and thermal properties according to their variances in anion and cation species of the ionic liquid, as well as the silk composition. We notice that the size and the number of interaction sites of the anion can play a role in thermal stability. The increase of the silk content promotes the increase of the crystallinity of the beta sheet in all prepared films.

ETD_8182

M.S.

Includes bibliographical references

by Amnah Hadadi

doi:10.7282/T3PG1VG4

ETD graduate

The author owns the copyright to this work.