Silver-cotton nanocomposites: nano-design of microfibrillar structure causes morphological changes and increased tenacity

Authors: Nam, Sunghyun; Condon, Brian; Delhom, Christopher - Chris; Fontenot, Krystal

Submitted to: Scientific Reports
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/27/2016
Publication Date: 11/16/2016
Citation: Nam, S., Condon, B.D., Delhom, C.D., Fontenot, K.R. 2016. Silver-cotton nanocomposites: nano-design of microfibrillar structure causes morphological changes and increased tenacity. Scientific Reports. 6(37320):1-10. https://doi.org/10.1038/srep37320.
DOI: https://doi.org/10.1038/srep37320

Interpretive Summary: This study reported how inorganic nanoparticles interact with a hierarchically ordered natural polymer. Through in-situ synthesis within partially dissolved cotton fiber, very small silver nanoparticles (12'3 nm in diameter) were grown between the helically oriented microfibrils. While growing, the nanoparticles electrostatically bound the microfibrils to improve the structural organization and change the fiber morphology. The reinforcement provided by the nanoparticles was demonstrated by increased tenacity, and the brittle failure behavior of the nanocomposite fiber was well described by the Weibull distribution. Notably, the concentration of nanoparticles exhibiting such influence on the macroscopic properties was less than 0.1% based on fiber weight. The large surface area of the nanoparticles resulting from the uniform dispersion is responsible for the maximized functionality observed. Such newly modified cotton fiber, in which functional nanoparticles were not only chemically attached but also physically trapped in the microfibrillar network, can be fabricated into nanoengineered textiles with permanent functions or designed into advanced devices that release functionalities under appropriate conditions (i.e., moist environments) in a controlled manner over a prolonged period of time.

Technical Abstract: The interactions of nanoparticles with polymer hosts have important implications for directing the macroscopic properties of composite fibers, yet little is known about such interactions with hierarchically ordered natural polymers due to the difficulty of achieving uniform dispersion of nanoparticles within semi-crystalline natural fiber. In this study we have homogeneously dispersed silver nanoparticles throughout an entire volume of cotton fiber. The resulting electrostatic interaction and distinct supramolecular structure of the cotton fiber provided a favorable environment for the controlled formation of nanoparticles (12'3 nm in diameter). With a high surface-to-volume ratio, the extensive interfacial contacts of the nanoparticles efficiently “glued” the structural elements of microfibrils together, producing a unique inorganic-organic hybrid substructure that reinforced the multilayered architecture of the cotton fiber.