The Impact of Composition and Morphology on Ionic Conductivity of Silk/Cellulose Bio-Composites Fabricated from Ionic Liquid and Varying Percentages of Coagulation Agents

• Published in: International journal of molecular sciences Vol. 21; no. 13; p. 4695
• Main Authors: Blessing, Bailey, Trout, Cory, Morales, Abneris, Rybacki, Karleena, Love, Stacy A, Lamoureux, Guillaume, O'Malley, Sean M, Hu, Xiao, Cruz, David Salas-de la
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI 30.06.2020; MDPI AG
• Subjects: Calorimetry, Differential Scanning; cellulose; Cellulose - chemistry; Coagulants; Dielectric Spectroscopy; Hydrophobic and Hydrophilic Interactions; ionic conductivity; Ionic Liquids; Microscopy, Atomic Force; Microscopy, Electron, Scanning; morphology; silk; Silk - chemistry; Spectroscopy, Fourier Transform Infrared; Static Electricity; Thermogravimetry; X-ray scattering; β-sheets; silk; X-ray scattering; ionic conductivity; morphology; cellulose; β-sheets; crystallinity
• ISSN: 1422-0067; 1661-6596; 1422-0067
• DOI: 10.3390/ijms21134695

Blended biocomposites created from the electrostatic and hydrophobic interactions between polysaccharides and structural proteins exhibit useful and unique properties. However, engineering these biopolymers into applicable forms is challenging due to the coupling of the material's physicochemical properties to its morphology, and the undertaking that comes with controlling this. In this particular study, numerous properties of the silk and microcrystalline cellulose biocomposites blended using ionic liquid and regenerated with various coagulation agents were investigated. Specifically, the relationship between the composition of polysaccharide-protein bio-electrolyte membranes and the resulting morphology and ionic conductivity is explored using numerous characterization techniques, including scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), X-ray scattering, atomic force microscopy (AFM) based nanoindentation, and dielectric relaxation spectroscopy (DRS). The results revealed that when silk is the dominating component in the biocomposite, the ionic conductivity is higher, which also correlates with higher β-sheet content. However, when cellulose becomes the dominating component in the biocomposite, this relationship is not observed; instead, cellulose semicrystallinity and mechanical properties dominate the ionic conduction.