Color Effects of Nanotextured Aluminum Surfaces: Characterization and Modeling of Optical Behavior

• Published in: Advanced engineering materials 2015-01, Vol.17 (1), p.45-51
• Main Authors: Matsapey, Natalia, Faucheu, Jenny, Flury, Manuel, Delafosse, David
• Format: Article
• Language: English
• Subjects: Aluminum; Anodizing; Backscattering; Color; Engineering Sciences; Fading; Fourier analysis; Materials; Nanostructure; Simulation
• ISSN: 1438-1656; 1527-2648
• DOI: 10.1002/adem.201400012

Surface finishes based on structural colors raise interest in product design and architecture in that long lasting colored surfaces can be produced with low risks if color fading. In this paper, aluminum surface are patterned through anodization with additional chemical post‐treatment. This electrochemical technique is advantageous in that it is already industrially mature and enables the treatment of large surfaces. The resulting surface shows self‐organized nanopatterns that lead to specific colored effects. In particular, colored effects similar to rainbow colors are observed in backscattering while the sample preserves its typical grayish metallic color when observed in direct reflection. Optical characterization of the sample have been performed and compared to optical simulations using Fourier modal method (FMM) method. A strong consistency between the simulation results and the experimental measurements has been obtained. It has been demonstrated that the color effects observed in backscattering are due to first order diffraction phenomena. Aluminum surfaces structured by anodization and chemical etching exhibit striking color effects observed on the backscattering side. Topographical characterization has provided direct visual evidence of the quasi‐periodic nature of the processed structures. A model structure is defined and simulated using a Fourier modal method code. A good agreement is found between the optical measurements and modeled behavior.