title: pH-Induced antireflection coatings derived from hydrogen-bonding-directed multilayer films.
abstract: Hydrogen-bonding-directed layer-by-layer assembled films, based on polystyrene-block-poly(acrylic acid) (PS-b-PAA) block copolymer micelles and poly(4-vinylpyridine) (P4VP), were successfully fabricated in methanol. Varying the PAA content in the PS-b-PAA micelles afforded control over the film growth properties, especially the multilayer film thickness. Interestingly, antireflection films with refractive indices that could be tuned between 1.58 and 1.28 were obtained by treatment with an aqueous HCl solution (pH 2.27), and the transmittance obtained was as high as 98.4%. In acid solution, the pyridine group was protonated, destroying the hydrogen bonding between P4VP and PAA. A concomitant pH-induced polymer reorganization in the multilayers resulted in a porous honeycomb-like texture on the substrate.
authors.affiliation: Department of Chemical Engineering, Polymer Research Institute, Pohang University of Science and Technology, Pohang 790-784, Korea.
authors.forename: Yingxi
authors.initials: Y
authors.lastname: Lu
authors.forename: Yeon Joo
authors.initials: YJ
authors.lastname: Choi
authors.forename: Ho Sun
authors.initials: HS
authors.lastname: Lim
authors.forename: Donghoon
authors.initials: D
authors.lastname: Kwak
authors.forename: Chiyeoung
authors.initials: C
authors.lastname: Shim
authors.forename: Seung Goo
authors.initials: SG
authors.lastname: Lee
authors.forename: Kilwon
authors.initials: K
authors.lastname: Cho