The worldwide annual production volume of textiles is nearly one hundred million metric tons. Most of these undergo treatments to achieve specific properties, such as color, hydrophobicity, antimicrobial, or UV protection, using chemicals that lead to collateral environmental consequences. There is great interest in developing alternative and sustainable strategies to achieve textile functionality that do not involve chemical treatment. Here we present a thermal drawing approach to achieve fiber surface gratings on a rectangular cross-section. We demonstrate directional wetting properties as well as structural coloration based on the gratings. Periods down to ≈ 600 nm were established on the surface of a fiber. Fabrics displaying higher-order diffraction peaks in the visible regime were produced from surface-patterned fibers using convetional weaving machinery.

We demonstrate a high-throughput method for synthesizing zinc selenide (ZnSe) in situ during fiber drawing. Central to this method is a thermally activated chemical reaction occurring across multiple interfaces between alternately layered elemental zinc- (Zn-) and selenium- (Se-) rich films embedded in a preform and drawn into meters of fiber at a temperature well below the melting temperature of either Zn or ZnSe. By depositing 50 nm thick layers of Zn interleaved between 1 μm thick Se layers, a controlled breakup of the Zn sheet is achieved, thereby enabling a complete and controlled chemical reaction. The thermodynamics and kinetics of this synthesis process are studied using thermogravimetric analysis and differential scanning calorimetry, and the in-fiber compound is analyzed by a multiplicity of materials characterization tools, including transmission electron microscopy, Raman microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction, all resulting in unambiguous identification of ZnSe as the compound produced from the reactive fiber draw. Furthermore, we characterize the in-fiber ZnSe/Se97S3 heterojunction to demonstrate the prospect of ZnSe-based fiber optoelectronic devices. The ability to synthesize new compounds during fiber drawing at nanometer scale precision and to characterize them at the atomic-level extends the architecture and materials selection compatible with multimaterial fiber drawing, thus paving the way toward more complex and sophisticated functionality.

The synthesis of a high-melting temperature semiconductor in a low-temperature fiber drawing process is demonstrated, substantially expanding the set of materials that can be incorporated into fibers. Reagents in the solid state are arranged in proximate domains within a fiber preform. The preform is fluidized at elevated temperatures and drawn into fiber, reducing the lateral dimensions and bringing the domains into intimate contact to enable chemical reaction. A polymer preform containing a thin layer of selenium contacted by tin–zinc wires is drawn to yield electrically contacted crystalline ZnSe domains of sub-100-nm scales. The in situ synthesized compound semiconductor becomes the basis for an electronic heterostructure diode of arbitrary length in the fiber. The ability to synthesize materials within fibers while precisely controlling their geometry and electrical connectivity at submicron scales presents new opportunities for increasing the complexity and functionality of fiber structures.

The opportunities and challenges of realizing sophisticated functionality by assembling many nanoscale devices, while covering large areas, remain for the most part unrealized and unresolved. In this work, we demonstrate the successful fabrication of an eight-device cascaded optoelectronic fiber structure in which components down to 100 nm are individually electrically addressed and can operate collectively to deliver novel functionality over large area coverage. We show that a tandem arrangement of subwavelength photodetecting devices integrated in a single fiber enables the extraction of information on the direction, wavelength, and potentially even color of incident radiation over a wide spectral range in the visible regime. Finally, we fabricated a 0.1 square meter single plane fiber assembly which uses polychromatic illumination to extract images without the use of a lens, representing an important step toward ambient light imaging fabrics.

We report a novel physical phenomenon in which a cylindrical shell undergoing a scaling process evolves into an ordered array of filaments upon reaching a characteristic thickness. We observe that the tendency to breakup is related to the material viscosity in a manner reminiscent of capillary instability. However, unlike the classical breakup of a fluid cylinder into droplets, the structural evolution in our system occurs exclusively in the cross sectional plane while uniformity is maintained in the axial direction. We propose a fluid front instability mechanism to account for the observed phenomena. The fleeting evolution of fluid breakup from a thin film to a filament array is captured in the frozen state by a thermal drawing process which results in extended lengths of solid sub-100 nm filaments encapsulated within a polymer fiber. Hundreds of glassy semiconductor filament arrays are precisely oriented within a polymer fiber matrix making electrical connections trivial. This approach offers unique opportunities for fabrication of nanometer scale devices of unprecedented lengths allowing simplified access and connectivity.