In electrospinning, the polymer fluid is typically in which state before ejection?

In electrospinning, the polymer fluid must be in a dissolved state to ensure it can be effectively drawn into a thin filament during the electrospinning process. When polymer solutions are created, they consist of polymer chains suspended in a solvent that allows them to flow and stretch under the influence of an electric field. This flow is crucial for forming continuous nanofibers.

When ejected from the spinneret, the solvent evaporates rapidly, solidifying the polymer into fine fibers that can be collected on a substrate. The necessity for the polymer to be in a dissolved state before ejection is fundamental to achieving the desired fiber morphology and mechanical properties. Other potential states, such as solidified or gel-like, would inhibit the ability to produce a fine, continuous fiber. Vaporized states would not provide the necessary material to create fibers. Thus, being in a dissolved state is essential for successful electrospinning.