Surface Modification via Atomic Layer Deposition

原子层沉积（ALD）是一种薄膜技术，其在很大程度上归功于化学气相沉积（CVD），但提供了对生长膜的原子级控制，因此提供了沉积复杂和分层薄膜的独特机会。所沉积的膜是无针孔的，并且至关重要的是，具有低缺陷密度，而固有的100%膜密度为给定材料提供了接近"理想"的特性。ALD是一种可用于表面改性的技术，并且与CVD相比具有低温技术的优点。该项目的目的是研究使用ALD来修饰表面，以调节表面的亲水/疏水特性（金属氧化物或聚合物）。ALD将用于通过将沉积模式从热沉积模式改变为等离子体增强沉积模式来将氧化物等表面改性为疏水或亲水。疏水性是一系列应用的关键表面性质，其中水吸附可使性能劣化，例如微机电系统（MEMS）上的保护涂层或聚合物基底上的气体扩散阻挡层。为了将表面如金属氧化物从亲水性改变为疏水性，通常需要使用氟化聚合物，这对环境有害。使用ALD，拟议的项目将利用沉积的低温和表面改性的容易性来实现聚合物涂层，例如用于防滑PVC安全地板和卫生PVC墙壁覆层的涂层。这种组合可以创造一种创新的新的“易于清洁”的涂层防滑地板和卫生的PVC墙壁覆层。这将与EPSRC的医疗保健和制造技术主题领域联系起来。PVC上的ALD沉积金属氧化物膜还可以作为PVC与环境之间的有效钝化层。然后，这可以扩展到其他应用中，例如太阳能电池的涂层。

Atomic Layer Deposition (ALD) is a thin-film technique that owes much to Chemical Vapour Deposition (CVD), but provides for atomic level control of the growing film and therefore unique opportunities for depositing complex and layered thin-films. The deposited films are pinhole free and, crucially, have a low defect density, whilst the inherent 100% film density provides near 'ideal' properties for a given material. ALD is a technique that can be used for surface modification and has the advantage that it is a low temperature technique in contrast to CVD. The aim of this project is to investigate the use of ALD to modify surfaces in order to tune the surface's hydrophilic/hydrophobic property (metal oxides or polymers). ALD will be used to modify surfaces, such as oxides, to be either hydrophobic or hydrophilic by changing deposition mode from thermal to plasma-enhanced. Hydrophobicity is a key surface property for a range of applications, where water adsorption can deteriorate the performance such as for protective coatings on microelectromechanical systems (MEMSs) or gas diffusion barrier layers on polymer substrates. To alter a surface, such as a metal oxide, from hydrophilic to hydrophobic, typically requires the use of fluorinated polymers, which are harmful to the environment. Using ALD, the proposed project will take advantage of the low temperature of deposition and the ease of modification of the surface to achieve coatings on polymers, such as those utilised in slip resistant PVC safety flooring and hygienic PVC wall cladding. Together this combination could create an innovative new 'easy-to-clean' coating for slip-resistant flooring and hygienic PVC wall cladding. This will link in with healthcare and manufacturing technologies theme area of the EPSRC. The ALD-deposited metal oxide films on PVC would also act as an effective passivation layer between the PVC and the environment. This could then be expanded into other applications such as in coatings for solar cells.