Nanostructured Antireflective and Thermoisolative Cicada Wings

详细信息    查看全文

• 作者：Junko Morikawa ; Meguya Ryu ; Gediminas Seniutinas ; Armandas Balčytis ; Ksenia Maximova ; Xuewen Wang ; Massimiliano Zamengo ; Elena P. Ivanova ; Saulius Juodkazis
• 刊名：Langmuir
• 出版年：2016
• 出版时间：May 10, 2016
• 年：2016
• 卷：32
• 期：18
• 页码：4698-4703
• 全文大小：450K
• 年卷期：0
• ISSN：1520-5827

文摘

Inter-related mechanical, thermal, and optical macroscopic properties of biomaterials are defined at the nanoscale by their constituent structures and patterns, which underpin complex functions of an entire bio-object. Here, the temperature diffusivity of a cicada (Cyclochila australasiae) wing with nanotextured surfaces was measured using two complementary techniques: a direct contact method and IR imaging. The 4–6-μm-thick wing section was shown to have a thermal diffusivity of α_⊥ = (0.71 ± 0.15) × 10^–7 m²/s, as measured by the contact temperature wave method along the thickness of the wing; it corresponds to the inherent thermal property of the cuticle. The in-plane thermal diffusivity value of the wing was determined by IR imaging and was considerably larger at α_∥ = (3.6 ± 0.2) × 10^–7 m²/s as a result of heat transport via air. Optical properties of wings covered with nanospikes were numerically simulated using an accurate 3D model of the wing pattern and showed that light is concentrated between spikes where intensity is enhanced by up to 3- to 4-fold. The closely packed pattern of nanospikes reduces the reflectivity of the wing throughout the visible light spectrum and over a wide range of incident angles, hence acting as an antireflection coating.