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. 2016 Jun 24;2(6):e1600417. doi: 10.1126/sciadv.1600417

Fig. 1. Preparation and characterization of the superhydrophilic-superhydrophobic Janus bilayer.

Fig. 1

(A) Schematic illustration of the Janus bilayer assembly: a multifunctional stack is fabricated by sequential electrospinning of a protective PVP, a superhydrophilic PCL, and a superhydrophobic PVC nanofiber layers on paper. This stack is shaped in a functional geometry and completed by adhering a PS nanofiber layer to a flexible PDMS substrate on the PVC surface by van der Waals (VDW) interaction. The protective PVP layer and paper are easily peeled off by hand. (B) Optical photographs show the isolated Janus bilayer and its cohesive and stretching properties. (C and D) SEM analysis at low-magnification (8.8k) and high-magnification (70k) images (insets, bottom right) of the Janus bilayer PVC and PCL surfaces and their contrasting wetting (insets, upper right). (E) FTIR spectroscopic analysis of the multilayer stack and isolated Janus bilayer confirming its PCL (orange line) and PVC (green line) composition. a.u., arbitrary units. (F) Dynamic mechanical stress-strain analysis (tension mode) of the Janus bilayer showing a soft rubbery nature, with a Young’s modulus (E) of 4.85 MPa.