TY - DATA T1 - Tough and Variable-Band-Gap Photonic Hydrogel Displaying Programmable Angle-Dependent Colors PY - 2018/01/04 AU - Md. Anamul Haque AU - Kei Mito AU - Takayuki Kurokawa AU - Tasuku Nakajima AU - Takayuki Nonoyama AU - Muhammad Ilyas AU - Jian Ping Gong UR - https://acs.figshare.com/articles/media/Tough_and_Variable-Band-Gap_Photonic_Hydrogel_Displaying_Programmable_Angle-Dependent_Colors/5756334 DO - 10.1021/acsomega.7b01443.s003 L4 - https://ndownloader.figshare.com/files/10140651 KW - angle-dependent colors KW - photonic gel sheet exhibits KW - tunable photonic KW - PAAm layer thickness KW - bulk geometry KW - gel sheet KW - rocking curves KW - sensor technologies KW - Variable-Band-Gap Photonic Hydrogel KW - Programmable Angle-Dependent Colors One-dimensional photonic crystals KW - light illumination angles KW - angle dependence KW - sheet geometry KW - angle-independent color KW - photonic band gaps KW - sheet surface KW - light modulation KW - angle-dependent behavior KW - photonic hydrogels KW - ductile polyacrylamide KW - photonic materials KW - index variation KW - lamellar bilayer KW - gel rod exhibits KW - band gaps KW - bulk geometries N2 - One-dimensional photonic crystals or multilayer films produce colors that change depending on viewing and light illumination angles because of the periodic refractive index variation in alternating layers that satisfy Bragg’s law. Recently, we have developed multilayered photonic hydrogels of two distinct bulk geometries that possess an alternating structure of a rigid polymeric lamellar bilayer and a ductile polyacrylamide (PAAm) matrix. In this paper, we focus on fabrication of composite gels with variable photonic band gaps by controlling the PAAm layer thickness. We report programmable angle-dependent and angle-independent structural colors produced by composite hydrogels, which is achieved by varying bulk and internal geometries. In the sheet geometry, where the lamellae are aligned parallel to the sheet surface, the photonic gel sheet exhibits strong angle-dependent colors. On the other hand, when lamellae are coaxially aligned in a cylindrical geometry, the gel rod exhibits an angle-independent color, in sharp contrast with the gel sheet. Rocking curves have been constructed to justify the diverse angle-dependent behavior of various geometries. Despite varying the bulk geometry, the tunable photonic gels exhibit strong mechanical performances and toughness. The distinct angle dependence of these tough photonic materials with variable band gaps could benefit light modulation in displays and sensor technologies. ER -