Water-soluble non-polymeric electrospun cyclodextrin nanofiber template for the synthesis of metal oxide tubes by atomic layer deposition

Abstract

We report on the suitability of water-soluble non-polymeric electrospun cyclodextrin (CD) nanofiber templates by using atomic layer deposition (ALD) to yield metal oxide tubes. To demonstrate this, water-soluble electrospun CD nanofibers were chosen as template to produce metal oxide tubes where we have tested two examples of ALD coatings, namely, Al₂O₃ and ZnO. After the ALD coating on the CD nanofibers, the CD core is simply dissolved in water to yield metal oxide tubes. Morphological investigations suggested that Al₂O₃ is smoother in contrast to ZnO which shows a grainy structure. Structural characterization evidenced amorphous Al₂O₃ and highly crystalline ZnO. Given the applicability of Al₂O₃ and ZnO in various contexts the ionic states of Al, Zn and O are also investigated. After the washing step to remove the CD core, Al₂O₃ developed some hydroxylation, while ZnO hosts various oxygen related functional groups.