SNM: Physical Nano-Engineering Approaches to Surface Coloration and their Industrial Scale Implementation in Anodized Aluminum

目前，铝表面的颜色是通过基于染料和颜料的涂层方法实现的，这些方法功能有限，容易划伤，并且在暴露于紫外线、热和元素时容易褪色。该奖项支持基础研究，以研究一种基于物理过程而不是化学过程的新方法，该方法将扩大颜色、功能的范围，从而扩大表面处理的应用。化学着色方法主要依赖于沉积在表面的染料和颜料对光的吸收，而物理着色通过控制光与纳米工程表面、涂层和材料的相互作用来产生颜色。研究中的“按设计上色”方法的灵感来自于自然界中发现的生物物理颜色的杰出例子，如孔雀尾羽、蝴蝶翅膀和珠宝甲虫的虹彩鳞片。铝阳极氧化是许多行业常用的材料，包括汽车、航空航天和消费品。所研究的物理着色方法将提高阳极氧化铝的外观、耐用性、可伸缩性和功能性，具有在许多制造领域广泛应用的潜力。将努力让代表性不足的群体参与研究，对各级学生进行培训，并将研究成果纳入课程和外联。预计这将对设备技术产生重大影响。该研究项目的目标是开发一种工业可扩展的铝表面物理着色方法，而不是化学着色方法。合成的颜色将具有更高的色调、饱和度和亮度值，以及改进的功能、易于维护和对元素的抵抗力。该方法将在纳米和微米尺度上控制材料的光学性质、干涉和衍射。需要研究和利用的关键物理现象包括金属纳米颗粒中的局域电子过程和量子化等离子体共振，周期、随机和准周期纳米图案介质中的长程光学衍射，以及超薄(小于10 nm)吸收层中的波位相调制。这些工艺将通过固有的可扩展制造技术实现，包括溅射薄膜沉积、喷涂和浸渍涂层、电化学浴、化学沉积和纳米冲压。这些方法的组合有望扩展目前工业目录中可用的颜色和表面处理，通过纯物理方法控制不透明度、光泽、亮度和虹彩，并产生可操作的和有试验支持的方法，将物理着色技术转换到制造环境中。

Currently the color of aluminum surfaces is achieved via dye- and pigment-based coating methods that have limited functionality, are vulnerable to scratching, and subject to color degradation when exposed to ultra-violet, heat, and the elements. This award supports fundamental research to investigate a novel method based on physical rather than chemical processes that will expand the range of color, function, and therefore, application of surface treatment. Chemical coloration methods rely on mostly absorption of light by dyes and pigments deposited on the surface, whereas physical coloration creates color by controlling the interaction of light with nano-engineered surfaces, coatings, and materials. The researched "color-by-design" method draws inspiration from brilliant examples of bio-physical color found in nature, such as peacock tail feathers, butterfly wings, and the iridescent scales of a jewel beetle. Anodized aluminum is a commonly used material in many industries, including automotive, aerospace, and consumer products. The reseached physical coloration method, which will enhance the appearance, durability, scalability, and functionality of anodized aluminum, has the potential to be broadly applied across many areas of manufacturing. Efforts will be made to involve under-represented groups in the research, train students at various levels and include the research results in curricula and outreach. The impact on device technology is expected to be significant.The goal of the research project is to develop an industry-scalable method for the physical, rather than chemical coloration of aluminum surfaces. The resultant colors will have higher hue, saturation, and brightness values, as well as improved functionality, ease of maintenance, and resistance to the elements. The method will control optical properties, interference and diffraction in materials at the nano- and micro-scales. Key physical phenomena to be investigated and utilized include local electronic processes and quantized plasmonic resonances in metal nanoparticles, long-range optical diffraction in periodic, or random and quasi-periodic nano-patterned dielectrics, as well as wave-phase modulations in ultra-thin (less than 10 nm) absorbing layers. These processes will be implemented via inherently scalable manufacturing techniques, including sputtering thin-film deposition, spray and dip coating, electrochemical baths, electroless deposition, and nano-stamping. The combination of these approaches is expected to expand the colors and finishes currently available in industry catalogs, enable the control of opacity, luster, brightness, and iridescence via purely physical means, and yield actionable and test-backed approaches for transitioning physical coloration techniques to a manufacturing setting.