Fig. 2

Preparation process of BPP-HNG and corresponding optical picture. (a) Fabrication process of BTO-PVDF composite film; Optical images of (b) 20 wt.% BTO-PVDF composite films and (c) 20 wt.% BTO-PVDF/PDMS composite film with SEM image (top right); (d) Optical image of 20 wt.% BTO-PVDF/PDMS composite film in the bended format; Optical images of the assembled BPP-HNG in (e) the front and (f) the side formats.