title: Layer-by-layer assembled films of cellulose nanowires with antireflective properties.
abstract: Natural nanowires (NWs) of cellulose obtained from a marine animal tunicate display surprisingly high uniformity and aspect ratio comparable with synthetic NWs. Their layer-by-layer assembled (LBL) films show strong antireflection (AR) properties having an origin in a novel highly porous architecture reminiscent of a "flattened matchsticks pile", with film-thickness-dependent porosity and optical properties created by randomly oriented and overlapping NWs. At an optimum number of LBL deposition cycles, light transmittance reaches nearly 100% (lambda approximately 400 nm) when deposited on a microscope glass slide and the refractive index is approximately 1.28 at lambda = 532 nm. In accordance with AR theory, the transmittance maximum red-shifts and begins to decrease after reaching the maximum with increasing film thickness as a result of increased light scattering. This first example of LBL layers of cellulose NWs can be seen as an exemplary structure for any rigid axial nanocolloids, for which, given the refractive index match, AR properties are expected to be a common property. Unique mechanical properties of the tunicate NWs are also a great asset for optical coatings.
authors.affiliation: Department of Chemical Engineering, University of Michigan, Ann Arbor, MI 48109, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Podsiadlo
authors.forename: Lang
authors.initials: L
authors.lastname: Sui
authors.forename: Yaseen
authors.initials: Y
authors.lastname: Elkasabi
authors.forename: Peter
authors.initials: P
authors.lastname: Burgardt
authors.forename: Jaebeom
authors.initials: J
authors.lastname: Lee
authors.forename: Ashwini
authors.initials: A
authors.lastname: Miryala
authors.forename: Winardi
authors.initials: W
authors.lastname: Kusumaatmaja
authors.forename: Mary R
authors.initials: MR
authors.lastname: Carman
authors.forename: Max
authors.initials: M
authors.lastname: Shtein
authors.forename: John
authors.initials: J
authors.lastname: Kieffer
authors.forename: Joerg
authors.initials: J
authors.lastname: Lahann
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Kotov
mesh_terms: D002482:Cellulose / Q000737:chemistry*; D008027:Light; D018625:Microscopy, Atomic Force; D008855:Microscopy, Electron, Scanning; D053770:Nanowires / Q000737:chemistry* / Q000648:ultrastructure; D016062:Porosity
chemical_list: D002482:Cellulose