Pfeiffer Tobias V, Kedia Puneet, Messing Maria E, Valvo Mario, Schmidt-Ott Andreas
Faculty of Applied Sciences, Delft University of Technology, Julianalaan 136, Delft 2628 BL, The Netherlands.
Solid State Physics, Lund University, Box 118, Lund 221 00, Sweden.
Materials (Basel). 2015 Mar 11;8(3):1027-1042. doi: 10.3390/ma8031027.
This article introduces a continuous, gas-phase method for depositing thin metallic coatings onto (nano)particles using a type of physical vapor deposition (PVD) at ambient pressure and temperature. An aerosol of core particles is mixed with a metal vapor cloud formed by spark ablation by passing the aerosol through the spark zone using a hollow electrode configuration. The mixing process rapidly quenches the vapor, which condenses onto the core particles at a timescale of several tens of milliseconds in a manner that can be modeled as bimodal coagulation. Gold was deposited onto core nanoparticles consisting of silver or polystyrene latex, and silver was deposited onto gold nanoparticles. The coating morphology depends on the relative surface energies of the core and coating materials, similar to the growth mechanisms known for thin films: a coating made of a substance having a high surface energy typically results in a patchy coverage, while a coating material with a low surface energy will normally "wet" the surface of a core particle. The coated particles remain gas-borne, allowing further processing.
本文介绍了一种在环境压力和温度下，使用一种物理气相沉积（PVD）方法在（纳米）颗粒上沉积薄金属涂层的连续气相法。通过使用空心电极配置使气溶胶通过火花区，将核心颗粒的气溶胶与通过火花烧蚀形成的金属蒸气云混合。混合过程迅速淬灭蒸气，蒸气在几十毫秒的时间尺度上以可建模为双峰凝聚的方式凝结在核心颗粒上。将金沉积在由银或聚苯乙烯胶乳组成的核心纳米颗粒上，将银沉积在金纳米颗粒上。涂层形态取决于核心材料和涂层材料的相对表面能，这与薄膜已知的生长机制类似：由具有高表面能的物质制成的涂层通常会导致斑驳的覆盖，而具有低表面能的涂层材料通常会“润湿”核心颗粒的表面。涂覆后的颗粒仍以气态形式存在，便于进一步处理。
