Stable dispersions of nanofibers are virtually unknown for synthetic polymers. They can complement analogous dispersions of inorganic components, such as nanoparticles, nanowires, nanosheets, etc as a fundamental component of a toolset for design of nanostructures and metamaterials via numerous solvent-based processing methods. As such, strong flexible polymeric nanofibers are very desirable for the effective utilization within composites of nanoscale inorganic components such as nanowires, carbon nanotubes, graphene, and others. Here stable dispersions of uniform high-aspect-ratio aramid nanofibers (ANFs) with diameters between 3 and 30 nm and up to 10 μm in length were successfully obtained. Unlike the traditional approaches based on polymerization of monomers, they are made by controlled dissolution of standard macroscale form of the aramid polymer, i.e. well known Kevlar threads, and revealed distinct morphological features similar to carbon nanotubes. ANFs are successfully processed into films using layer-by-layer (LBL) assembly as one of the potential methods of preparation of composites from ANFs. The resultant films are transparent and highly temperature resilient. They also display enhanced mechanical characteristics making ANF films highly desirable as protective coatings, ultrastrong membranes, as well as building blocks of other high performance materials in place of or in combination with carbon nanotubes.

Polymer-based solid electrolytes containing ceramic nanoparticles are attractive alternatives to liquid electrolytes for high-energy density Li batteries. In this study, three different types of fillers have been dispersed in poly­(ethylene) oxide (PEO) polymer matrices, and the effects on the resulting ionic conductivity of the nanocomposites have been examined. In this respect, the efficacy of one active, liquid-feed flame spray pyrolysis synthesized amorphous Li1.3Al0.3Ti1.7(PO4)3 (LATP), and two passive filler materials, TiO2 and fumed silica nanoparticles, are compared. Nanocomposite electrolytes are prepared with up to 20 wt % particle loadings. PEO/LiClO4 with 10 wt % LATP nanoparticles exhibits an ionic conductivity of 1.70 × 10–4 S·cm–1 at 20 °C, the highest among the surveyed systems, despite exhibiting comparable or higher degrees of crystallinity and glass transition temperatures than the systems containing passive fillers. The ionic conductivity of the composites with LATP nanoparticles exceed that of the polymer matrix by 1 to 2 orders of magnitude. We attribute this remarkable enhancement to cation transport within the interphase region surrounding the particles, which achieves percolation at low nanoparticle loading. The development of this interphase structure is influenced by the active nature of the LATP filler, and we estimate the inherent conductivity of the interphase to be 3 to 4 times higher than the maximum measured value.

Conventional casting–sintering of flame made nanoparticles result in high density and ionic conductivity c-LLZO flexible thin film membranes.

Natural nanowires (NWs) of cellulose obtained from a marine animal tunicate display surprisingly high uniformity and aspect ratio comparable with synthetic NWs. Their layer-by-layer assembled (LBL) films show strong antireflection (AR) properties having an origin in a novel highly porous architecture reminiscent of a "flattened matchsticks pile", with film-thickness-dependent porosity and optical properties created by randomly oriented and overlapping NWs. At an optimum number of LBL deposition cycles, light transmittance reaches nearly 100% (lambda approximately 400 nm) when deposited on a microscope glass slide and the refractive index is approximately 1.28 at lambda = 532 nm. In accordance with AR theory, the transmittance maximum red-shifts and begins to decrease after reaching the maximum with increasing film thickness as a result of increased light scattering. This first example of LBL layers of cellulose NWs can be seen as an exemplary structure for any rigid axial nanocolloids, for which, given the refractive index match, AR properties are expected to be a common property. Unique mechanical properties of the tunicate NWs are also a great asset for optical coatings.