Heterogeneous fiber fluid reservoirs

The instant disclosure is directed to a heterogeneous fiber fluid reservoir for holding and delivering fluid. A reservoir may comprise a rod having a core component and a surrounding component. Each of the core component and the surrounding component may comprise fibers. The core component may have a first property, and the surrounding component may have a second property different from the first property, or the core component and the surrounding component may each have a different value or range of values for the same property. Alternatively, a reservoir may comprise a rod that includes fibers and has a cross-sectional diameter. At least one property of the rod may vary in value along the cross-sectional diameter of the rod. The property may include, for example, fiber bulk density, fiber diameter, fiber material, fiber morphology, fiber surface tension, capillary force, fluid absorption capacity, color, or combinations thereof.