Nanomanufacturing of Surfaces for Energy Efficient Icing Suppression

用于节能结冰的表面纳米制造

• 批准号: EP/N006577/1
• 负责人: Manish K. Tiwari
• 金额: $ 12.82万
• 依托单位: University College London
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2015
• 资助国家: 英国
• 起止时间: 2015 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FN006577%2F1
• 关键词: Nanomanufacturing; Surfaces; Energy; Efficient; Icing

Undesirable ice formation causes a lot of disruption - from impairing energy efficiency of household refrigerators to causing destructive accidents due to ice accumulation on infrastructure components and airplanes. The proposed research aims to address this ubiquitous problem using precise, but potentially scalable techniques to nanoengineer icephobic surfaces that can suppress ice formation, resist impact of cold drops and have minimal adhesion to ice. The proposal is motivated to provide a viable, passive and energy efficient alternative to the currently employed anti-icing techniques, which rely either on electro-thermal systems that affect the system efficiency and running costs, or make use of environmentally adverse chemicals. The surface nanoengineering to be employed will involve a precise control of both the surface texture at nanoscale and the surface hydrophobicity. The appropriate combination of these two aspects is expected to not only suppress ice formation in severely supercooled conditions (at sub-zero temperatures), but to resist impact of high speed supercooled droplets and minimize adhesion of ice on the surface - all these aspects are relevant to icing in practical applications and will be tested in the current work.The ambition of the proposal is to make nanotextured surfaces with nanohole arrays with better than 10 nm precision (i.e. resolution). Such precise and rounded morphologies are expected to suppress ice formation according to the thermodynamic heterogeneous ice nucleation framework previously introduced by the PI and supported by atomistic modelling results in the literature. In addition, self-assembly of hydrophobic molecules on the surfaces will allow a control over the surface energy, which, in combination with the texture control, will help produce superhydrophobic surfaces that can resist impalement by high speed, cold drops, and have low ice adhesion. The drop impalement resistance can help avoid icing on aircrafts and outdoor infrastructure elements in freezing rain conditions. As a proof-of-concept for a potentially scalable, precise nanotexturing, current project will exploit electrochemical anodisation of metals through polymeric nanohole films, prepared using block-copolymers (BCP), serving as templates. The surface texturing will be limited to top ~100 nm or lower thickness of the substrate and only mild anodisation conditions will be used. The templated anodisation is well suited to aluminium and titanium - substrates prevalent in aerospace, refrigeration and automotive industry; however, similar templated etching approaches can be developed for substrates in other applications (see the PATHWAYS TO IMPACT section). PI's prior work has shown that thermally conductive substrates are better for arresting frost formation from cold drops lying on the surface, thus the metallic substrates are a very good choice. In addition, the current work, for the first time, introduces a novel means to use simple anodic surface projections to improve the resolution of BCP nanohole templates themselves to ~10 nm precision - surfaces anodised through these precise templates are expected to be ideally suited for icephobicity. The resulting anodised substrates will be rendered hydrophobic by functionalizing with hydrophobic molecules. These precisely nanotextured hydrophobic surface are expected to suppress icing not only due to their rounded nanoscale morphology, but will also feature minimal solid-liquid contact area, thereby further suppressing the icing probability. The synthesized surfaces will be subjected to three set of tests: their ability to resist impalement by high speed, supercooled drops (target: 25 m/s); ability to delay ice formation in supercooled conditions at different humidity levels (target: 2 hours at -25 degrees Centigrade); and minimize their adhesion to frozen (ice) drops.

不希望的冰形成会造成很多破坏-从损害家用冰箱的能源效率到由于基础设施部件和飞机上的冰积累而造成破坏性事故。拟议的研究旨在使用精确但可能可扩展的技术来解决这个普遍存在的问题，以纳米工程化的疏冰表面，可以抑制冰的形成，抵抗冷滴的影响，并具有最小的粘附冰。该提案旨在为目前采用的防冰技术提供一种可行的、被动的和节能的替代方案，这些技术要么依赖于影响系统效率和运行成本的电热系统，要么使用对环境有害的化学品。所采用的表面纳米工程将涉及在纳米尺度下对表面纹理和表面疏水性的精确控制。这两个方面的适当结合，预计不仅可以抑制严重过冷条件下的结冰（在零度以下的温度下），但是为了抵抗高速过冷液滴的冲击并且使冰在表面上的粘附最小化，所有这些方面都与实际应用中的结冰有关，并将在目前的工作中进行测试。该提案的目标是制造具有纳米孔阵列的纳米织构表面具有优于10 nm的精度（即分辨率）。根据PI先前引入的热力学非均质冰成核框架，并得到文献中原子模型结果的支持，这种精确和圆形的形态有望抑制冰的形成。此外，疏水分子在表面上的自组装将允许控制表面能，这与纹理控制相结合，将有助于产生超疏水表面，其可以抵抗高速、冷滴的刺穿，并且具有低的冰粘附性。抗跌落刺穿性可以帮助避免在冻雨条件下飞机和室外基础设施元件上结冰。作为一个潜在的可扩展的，精确的纳米纹理的概念验证，目前的项目将利用金属的电化学阳极化通过聚合物纳米孔膜，使用嵌段共聚物（BCP）制备，作为模板。表面纹理将被限制在基底的顶部~100 nm或更低的厚度，并且仅使用温和的阳极化条件。模板阳极化非常适合铝和钛-航空航天、制冷和汽车工业中普遍使用的基材;然而，可以为其他应用中的基材开发类似的模板蚀刻方法（参见“影响路径”部分）。PI先前的工作表明，导热基底更适合于阻止表面上的冷滴形成霜，因此金属基底是一个非常好的选择。此外，目前的工作首次引入了一种新的方法，使用简单的阳极表面投影来将BCP纳米孔模板本身的分辨率提高到约10 nm的精度-通过这些精确模板阳极化的表面预计非常适合于疏冰性。所得的阳极化基材将通过用疏水分子官能化而呈现疏水性。这些精确的纳米纹理疏水表面预期不仅由于其圆形纳米级形态而抑制结冰，而且还具有最小的固液接触面积，从而进一步抑制结冰概率。合成的表面将经受三组测试：它们抵抗高速过冷液滴刺穿的能力（目标：25 m/s）;在不同湿度水平下在过冷条件下延迟冰形成的能力（目标：在-25摄氏度下2小时）;以及使它们对冷冻（冰）液滴的粘附最小化。

项目成果

Nanotextured Aluminum-Based Surfaces with Icephobic Properties

• DOI: 10.1080/01457632.2019.1640461
• 发表时间: 2020-11
• 期刊: Heat Transfer Engineering
• 影响因子: 2.3
• 作者: Michael Grizen;T. Maitra;J. Bradley;M. Tiwari

Compression molding processed superhydrophobic CB/CeO2/PVDF/CF nanocomposites with highly robustness, reusability and multifunction

• DOI: 10.1016/j.colsurfa.2020.124533
• 发表时间: 2020-04
• 期刊: Colloids and Surfaces A: Physicochemical and Engineering Aspects
• 作者: Binrui Wu;Jiajie Lyu;Chaoyi Peng;Jun Liu;S. Xing;D. Jiang;S. Ju;M. Tiwari