Directed growth of calcein/nile red coaxial nanowire arrays via a two-step dip-coating approach

Superhydrophobic pillar-structured substrates are successful guides in the control of rupturing liquid films, then they can precisely position 1D nanostructures in a well-defined arrangement. Herein we demonstrate a two-step dip-coating approach to introduce a sheathing layer along aligned nanowires upon superhydrophobic pillar-structured surfaces, yielding precisely positioned core-sheath coaxial nanowire (CNWs) arrays. Notably, fluorescence resonance energy transfer (FRET) behaviors have appeared inside the as-prepared CNWs due to the contact between the donors and the acceptors in the CNW core and sheathing layer, respectively. Due to the FRET behavior inside the bead-shaped CNWs, these hierarchical 1D nanostructures could display different responses to diverse compounds.