coreandsheath

Coreandsheath is a term used to describe a class of two-component structures in which a functional core material is encased by a surrounding sheath. This architecture appears in polymer science, nanotechnology, textiles, and energy storage. The core provides the primary function—electrical, optical, catalytic, or mechanical—while the sheath offers protection, environmental isolation, processing advantages, or tunable interfacial properties. The phrase is often used interchangeably with core-shell concepts, though core-and-sheath emphasizes the distinct layering of core and sheath.

Fabrication methods include coaxial electrospinning and coaxial wet-spinning to produce core-and-sheath fibers, coextrusion to form composite structures, and layer-by-layer deposition to tailor interfaces. In nanosystems, core-sheath or core-shell particles are created by precipitation or surface modification to produce functional shells around a core material. The terminology varies in the literature, with core-sheath and core-shell often used interchangeably.

Applications span drug delivery, where a polymeric sheath controls release and protects the core, to energy storage, where a sheath enhances chemical stability and cycle life. In textiles and coatings, the sheath improves durability, environmental resistance, and wash-fastness; in optics and electronics, cladding or protective shells can improve performance and longevity. Examples include polymeric core-and-sheath fibers and nanoparticles with metal-oxide cores and polymer or silica shells.

Challenges include achieving strong interfacial adhesion, matching mechanical properties, controlling diffusion across the boundary, and scaling fabrication for industrial use. Research focuses on materials compatibility, processing control, and multifunctionality of core-and-sheath systems.