Facile fabrication of biomimetic films with the microdome and tapered nanonipple hierarchical structure possessing high haze, high transmittance, anti-fouling and moisture self-cleaning functions

Abstract

Inspired by the micro and nano hierarchical structure of rose petals and the tapered nanonipple structure of cicada wings, a designed microdome and tapered nanonipple hierarchical (MTNH) structure is fabricated by a simple thermal polymerization method based on the hierarchical alumina template. The total transmittance, haze and anti-fouling properties of the microdome, tapered nanonipple and MTNH structured polymer films are compared, respectively. It is found that only the MTNH can simultaneously possess the high haze, high total transmittance and anti-fouling properties, because MTNH can combine both the merits of microdome and tapered nanonipple structure. The simulation results based on finite-difference time-domain (FDTD) analysis correspond to the experimental results very well. The average total transmittance and haze of MTNH among the wavelength between 400 and 1100 nm are 93.9% and 89.7%, respectively. After the MTNH sample is dipped into and pulled out of the graphite powder, it also exhibits high transmittance (82.9%). In addition, MTNH can achieve condensed microdroplets self-propelling property after chemical modification to realize the moisture self-cleaning. This multi-functional surface has high potentials to be applied in optical and electro-optical devices to simultaneously enhance the light utilization efficiency and improve the use of comfort.