(14e) Biomimetic Production of Polymer Fibers from Reversibly Cross-Linked Polysaccharide Networks in Water

Polymer fibers are important structural components in textiles, composite materials, and numerous materials for biomedical applications. The demand for tough, biocompatible materials produced by simple processing techniques has led to significant interest in materials inspired by natural fibers such as spider silks.^1,2 Traditional methods of fiber production typically require spinning processes that suffer from high energy costs and are dependent on organic solvents, amongst other physical limitations due to burdensome protocols and highly viscous polymer solutions.³ This work describes a biomimetic technique for fabricating polymer fibers that is both operationally simple and performed at room temperature in aqueous solutions. Similar to spider silks, these fibers are produced by pultrusion, rather than electrospinning or extrusion, and can be drawn to > 1m in length from a viscous liquid. The liquid-phase precursor consists of a network of polysaccharides and small, branched polymers reversibly bound by dynamic covalent cross-links that rapidly break and reform, allowing for fiber formation. The effects of the chemical structure, molecular weight, and extent of branching of the cross-linker on the material properties of the bulk liquid and resulting polymer fibers are investigated. Mechanical testing and microscopy studies of the fibers provide insight into the origin of these properties, in particular, high ductility. Overall, a molecular understanding of how the polysaccharide network translates to macroscopic properties provides a strategy for efficient production and rational design of fibrous biomaterials. Unlike most polymer fibers, the described structural properties directly result from a dynamic cross-linked network. This design expands the potential of these materials from being used for their physical architectures, such as in porous scaffolds for tissue growth,⁴ to being used for their chemical properties, such as in stimulus-responsive drug delivery systems.

References:

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2. Wu, Y. et al Natl. Acad. Sci. 2017, 114, 8163–8168.
3. I. C.; Fang, D.; Hsiao, B. S.; Okamoto, A.; Chu, B. Biomacromolecules 2004, 5, 1428–1436.
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