|BAEK, INSUCK - Oak Ridge Institute For Science And Education (ORISE)|
Submitted to: Nanoscale Advances
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 6/20/2022
Publication Date: 6/20/2022
Citation: Nam, S., Baek, I., Hillyer, M.B., He, Z., Barnaby, J.Y., Condon, B.D., Kim, M.S. 2022. Thermosensitive textiles by silver nanoparticle-filled brown cotton fibers. Nanoscale Advances. 4:3725-3736. https://doi.org/10.1039/D2NA00279E.
Interpretive Summary: This study demonstrated that filling a small amount of Ag NPs (12,500 mg/kg based on the dry weight of the fiber) inside brown cotton fiber altered the thermal response and heat transfer properties of brown cotton. The condensed tannins, a natural component responsible for the color of brown cotton, acted as a reducing agent, allowing brown cotton to produce Ag NPs within its internal structure without the use of any external reducing and stabilizing agents. The Vis/NIR reflectance and fluorescence hyperspectral images showed the uniformity of the in situ synthesis of Ag NPs throughout the nonwoven fabric. The dispersion of individual Ag NPs with about 28 nm in diameter was confirmed by imaging and analyzing the cross-section of fibers. Ag NPs were concentrated in the lumen of the fiber. Ag NPs filled into brown cotton fiber effectively transferred heat to the fiber medium, lowering the temperature of thermal decomposition for cellulose under both nitrogen and air environments. In an air environment, Ag NP-filled brown cotton required a greater activation energy for the thermal decomposition than control cotton. Ag NPs improved the thermal effusivity of brown cotton, rendering its fabric to have warmer feel and promoted the thermal response of the fabric under heat treatments. The results help understand how Ag NP insertion in the microfibrillar structure influence the macroscopic thermal properties of cotton under heat.
Technical Abstract: Nanomaterials can add specific function and properties to fibers. However, as nanocomposite formation for natural cellulosic fibers has been challenging, little information is available on how the embedded nanomaterials alter the properties of cellulosic fibers. Here we filled silver nanoparticles (Ag NPs) into brown cotton fibers to examine thermosensitive properties. Using naturally present tannins in brown cotton fiber as a reducing agent, Ag NP-filled brown cotton fiber (nanoparticle diameter of about 28 nm, weight fraction of 12,500 mg/kg) was produced through a one-step process without using any external agents. The in situ formation of Ag NPs was uniform across the nonwoven cotton fabric and were microscopically concentrated in the lumen of the fiber. The insertion of Ag NPs into the fibers shifted the thermal decomposition of cellulose to lower temperatures with increased activation energy and promoted heat release during combustion. Ag NPs lowered the thermal effusivity of the fabric, inducing the fabric to feel warmer than the control brown cotton. Similarly, Ag NP-filled brown cotton was more effectively heated to higher temperatures than control brown cotton under the same heating treatments.