Multi-layered Nanocoating of Nano and Submicron Sized Particles at Large Scale

原子层沉积（ALD）工艺将用于大规模修饰超细颗粒的表面化学性质，并研究修饰后的颗粒对UVA/UVB透射率和自组装的效用。在研究的一个方面，多层和纳米陶瓷膜将放置在单个初级亚微米和纳米级无机颗粒的表面，使用流化床工艺。研究工作包括理解亚微米和纳米级颗粒的流化行为，这些颗粒受颗粒间力的影响，流化为动态聚集体，以及随后纳米涂层单个初级颗粒流化为轻聚集体的能力。这是第一次尝试将纳米厚多层膜放置在流化颗粒上。防晒UVA/UVB系统（ZnO/TiO2）已被选择，以提供一个很好的表征应用与明确的方法来测试复合粉末在非水配方（防晒乳液）中的行为。在研究的另一方面，ALD将无机纳米膜放置在纳米球形颗粒的表面，以控制其表面电荷（阴离子和阳离子）。将研究含有等浓度的带相反电荷的纳米球的溶液中离子自组装成纳米球“盐”。研究将扩展到纳米基板颗粒上的双层涂层，其中内层赋予纳米颗粒光学功能，外层赋予离子自组装的电荷功能。以这种方式，将研究具有可控衍射图案的光子晶体阵列的自组装。该项目的总体目标是通过ALD展示超细颗粒上的多层膜，以及这种表面修饰颗粒在配方和纳米制造阵列中的应用。这项新颖的研究提供了纳米颗粒表面化学的大规模控制，以促进在配方中使用功能化纳米颗粒和制造新的成分。所研究的纳米颗粒表面涂覆方法是可行的，并广泛适用于许多系统。这项研究为两名博士生和大约20名本科生提供了为期三年的独特教育体验。当地的工业合作伙伴ALD Nanosolutions已同意与学生合作（例如，通过顶点设计项目），以更好地了解研究的科学和应用方面，并促进技术转让。

Atomic Layer Deposition (ALD) processing will be carried out to modify the surface chemistry of ultrafine particles at large scale and to investigate the utility of the modified particles for UVA/UVB transmittance and self assembly. In one aspect of the research, multilayered and nanolaminated ceramic films will be placed on the surface of individual primary submicron and nanosized inorganic particles using a fluidized bed process. The research effort includes an understanding of the fluidization behavior of the submicron and nanosized particles that are affected by interparticle forces and that fluidize as dynamic aggregates, and the subsequent ability to nanocoat individual primary particles fluidizing as light aggregates. This is a first attempt to place nanothick multilayers on fluidized particles by ALD. A sunscreen UVA/UVB system (ZnO/TiO2) has been selected to provide for a well characterized application with definitive methods for testing the composite powder behavior in non-aqueous formulations (sunscreen lotions). In another aspect of the research, inorganic nanofilms will be placed on the surface of nanospherical particles by ALD to control their surface charge (anionic and cationic). Solutions containing equal concentration of oppositely charged nanospheres will be investigated for ionic self-assembly into nanospherical "salts". The investigation will be extended to bilayered coatings on nanosized substrate particles where the inner layer imparts optical functionality on the nanoparticles and the outer layer imparts charge functionality for ionic self assembly. In this manner, the self assembly of photonic crystalline arrays with controlled diffraction patterns will be investigated. The overall goal of the project is to demonstrate multi-layered films on ultrafine particles by ALD and the utility of such surface modified particles in formulations and nanofabricated arrays.This novel research provides for the large scale control of nanoparticle surface chemistry to facilitate the use of functionalized nanoparticles in formulations and for fabricating novel components. The nanoparticle surface coating method to be investigated is enabling and widely applicable to many systems. This research provides for a unique educational experience for two Ph.D. students and approximately 20 undergraduates over the three year program. A local industrial partner, ALD Nanosolutions, has agreed to work with the students (e.g., through capstone design projects) to better understand both the scientific and applied aspects of the research and to facilitate technology transfer.