Controlled fragmentation of multimaterial fibres and films via polymer cold-drawing.

Polymer cold-drawing is a process in which tensile stress reduces the diameter of a drawn fibre (or thickness of a drawn film) and orients the polymeric chains. Cold-drawing has long been used in industrial applications, including the production of flexible fibres with high tensile strength such as polyester and nylon. However, cold-drawing of a composite structure has been less studied.

Digital design of multimaterial photonic particles.

Scattering of light from dielectric particles whose size is on the order of an optical wavelength underlies a plethora of visual phenomena in nature and is a foundation for optical coatings and paints. Tailoring the internal nanoscale geometry of such "photonic particles" allows tuning their optical scattering characteristics beyond those afforded by their constitutive materials-however, flexible yet scalable processing approaches to produce such particles are lacking. Here, we show that a thermally induced in-fiber fluid instability permits the "digital design" of multimaterial photonic particles: the precise allocation of high refractive-index contrast materials at independently addressable radial and azimuthal coordinates within its 3D architecture.

In-fiber production of polymeric particles for biosensing and encapsulation.

Polymeric micro- and nanoparticles are becoming a mainstay in biomedicine, medical diagnostics, and therapeutics, where they are used in implementing sensing mechanisms, as imaging contrast agents, and in drug delivery. Current approaches to the fabrication of such particles are typically finely tuned to specific monomer or polymer species, size ranges, and structures. We present a general scalable methodology for fabricating uniformly sized spherical polymeric particles from a wide range of polymers produced with complex internal architectures and continuously tunable diameters extending from the millimeter scale down to 50 nm.

Structured spheres generated by an in-fibre fluid instability.

From drug delivery to chemical and biological catalysis and cosmetics, the need for efficient fabrication pathways for particles over a wide range of sizes, from a variety of materials, and in many different structures has been well established. Here we harness the inherent scalability of fibre production and an in-fibre Plateau-Rayleigh capillary instability for the fabrication of uniformly sized, structured spherical particles spanning an exceptionally wide range of sizes: from 2 mm down to 20 nm. Thermal processing of a multimaterial fibre controllably induces the instability, resulting in a well-ordered, oriented emulsion in three dimensions.

Multimaterial preform coextrusion for robust chalcogenide optical fibers and tapers.

The development of robust infrared fibers is crucial for harnessing the capabilities of new mid-infrared lasers. We present a novel approach to the fabrication of chalcogenide glass fiber preforms: one-step multimaterial extrusion. The preform consists of a glass core and cladding surrounded by a built-in, thermally compatible, polymer jacket for mechanical support.

Thermal drawing of high-density macroscopic arrays of well-ordered sub-5-nm-diameter nanowires.

We investigate the lower limit of nanowire diameters stably produced by the process of thermal fiber drawing and fiber tapering. A centimeter-scale macroscopic cylindrical preform containing the nanowire material in the core encased in a polymer scaffold cladding is thermally drawn in the viscous state to a fiber. By cascading several iterations of the process, continuous reduction of the diameter of an amorphous semiconducting chalcogenide glass is demonstrated.