Sequential Infiltration Synthesis for High-Precision Fabrication of Applied Ceramic Fibers with Designed Nanostructures─Nanowires, Nanobelts, and Core–Shell Fibers

Abstract

Inorganic nanofibers are advantageous materials in a variety of applications such as gas sensing and catalysis due to their 1D morphology, high surface area, and versatile properties. Here, we present a new approach for high-precision ceramic fiber fabrication of AlO x , ZnO, and AlO x -ZnO core–shell fibers, with programmable dimensions, morphology, and surface structure, through controlled growth of metal oxides within electrospun polymer fibers using sequential infiltration synthesis (SIS). Designed growth profiles within the fiber are achieved through controlled diffusion of the SIS gaseous precursors; moderate growth gradients lead to spherical fibers after polymer removal, while sharp growth gradients result in fiber buckling into nanobelt morphology. To move towards complex inorganic fiber architectures, we extend single-metal-oxide SIS into spatially controlled, multi-material SIS and demonstrate AlO x -ZnO core–shell fibers with tunable core and shell thicknesses. The core–shell fibers are fabricated in a single SIS process, where the location of each metal oxide is controlled by its diffusion time. This study opens up new possibilities for high-precision, complex architecture and composition ceramic fibers fabrication process.

Revealing the 3D Structure of Block Copolymers with Electron Microscopy: Current Status and Future Directions

“…Our later work expanded the technique to homopolymer electrospun fibers. 98 To conclude, (S)TEMT has a vital role in deciphering BCP characteristics, understanding the processes that govern BCP assembly, and allowing the rational design of BCP nanostructures in diverse platforms. It provides researchers with a nondestructive, high-resolution, accurate understanding of the system at hand, including the important effects of boundary conditions in the four confinement types discussed above.…”

“…We then applied simultaneous TEM and energy-dispersive X-ray (EDX) tomography to study the 3D heterostructures formed. Our later work expanded the technique to homopolymer electrospun fibers …”

Developing Quantitative Nondestructive Characterization of Nanomaterials: A Case Study on Sequential Infiltration Synthesis of Block Copolymers

“…14 Interestingly, SIS has also been applied to the development of functional materials with scalable dimensions for applications including composite ultrafiltration membranes15, 16 and ceramic fibers for electrospinning. 17 The exploitation of such advanced materials requires good control of the infiltration process and its mechanism through in situ analytical methods 18 as well as an accurate characterization of the outcome corresponding to the process parameters ex situ and of the resulting functional properties of the materials. 3,19 Among in situ analyses, Fourier-transform infrared (FTIR) spectroscopy has been used for monitoring the modifications of adsorption peaks corresponding to the interactions between polymers' functional groups and reactants, 20,21 aluminum (TMA) infiltration in PS/PMMA-containing systems.…”

“…Moreover, SIS constitutes a valid solution for tuning the polymer optical constants for coatings, for hyperbolic metamaterial engineering, , and for altering the polymers’ electrical conductivity for nanoelectronics applications . Interestingly, SIS has also been applied to the development of functional materials with scalable dimensions for applications including composite ultrafiltration membranes15, and ceramic fibers for electrospinning …”

Ibuprofen-Loaded ZnO Nanoparticle/Polyacrylonitrile Nanofibers for Dual-Stimulus Sustained Release of Drugs

“…Numerous medicated nanoparticles have found their potential applications in drug delivery, while electrospinning has wide application prospects in the field of transdermal drug delivery. − Electrospinning is able to treat many kinds of fluids, including solutions, , emulsions, , and nano-suspensions, , and in several manners such as blending, , coaxial, and multiple fluid . Drug-loaded electrospun nanofiber membranes have large specific surface areas, high porosity, and high fluid absorption, which induce a humid environment on the skin cuticle, allowing the fiber membrane to closely fit to the skin, thereby helping drugs enter systemic circulation in the way of dissimilar diffusion along a concentration gradient. − Polyacrylonitrile (PAN) is widely used for electrospinning because of its good electrospinnability and stability .…”