Delayed Dissolution and Small Molecule Release from Atomic Layer Deposition Coated Electrospun Nanofibers

Electrospun poly (vinyl alcohol) nanofibers are coated with aluminum oxide using atomic layer deposition (ALD) to control the dissolution rate of the nanofiber mats in high-humidity and aqueous environments. In this regard, ALD offers an effective method to provide a robust, conformal coating to the entire nanofiber surface without modifying the core material. The thickness of the coating, controlled by varying the number of ALD cycles from 2 to 200, enables tuning of the nanofiber stability in water from a few seconds for an uncoated sample to over 5 weeks for a 200 cycle coated sample. Changing the rate of nanofiber dissolution modulates the release of embedded small molecules within the polymer matrix from minutes to weeks while minimizing the burst effect typically associated with nanoscale systems. This simple nanofiber coating technique shows great potential as a method to tune shelf-life, mat degradation, and small molecule release from highly water-soluble polymers, hitherto unexplored, in a wide range of fields, including biomedical, agricultural, and packaging.