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Bio‐inspired Highly Scattering Networks via Polymer Phase Separation
Author(s) -
Syurik Julia,
Jacucci Gianni,
Onelli Olimpia D.,
Hölscher Hendrik,
Vignolini Silvia
Publication year - 2018
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.201706901
Subject(s) - materials science , scattering , transmittance , refractive index , polymer , porosity , phase (matter) , light scattering , micrometer , optics , nanotechnology , optoelectronics , composite material , chemistry , physics , organic chemistry
A common strategy to optimize whiteness in living organisms consists in using 3D random networks with dense and polydisperse scattering elements constituted by relatively low refractive index materials. Inspired by these natural architectures, a fast and scalable method to produce highly scattering porous polymer films via phase separation is developed. By varying the molecular weight of the polymer, the morphology of the porous films is modified, and therefore their scattering properties are tuned. The achieved transport mean free paths are in the micrometer range, improving the scattering strength of analogous low refractive index systems, e.g., standard white paper, by an order of magnitude. The produced porous films show a broadband reflectivity of ≈75% while only 4 µm thick. In addition, the films are flexible and can be readily index‐matched with water (i.e., they become transparent when wet), allowing for various applications such as coatings with tunable transmittance and responsive paints.