Wetting and fouling on polymeric films

聚合物薄膜的润湿和结垢

• 批准号: 175166909
• 负责人: Professor Dr.-Ing. Hans-Jörg Bart
• 金额: --
• 依托单位: Lehrstuhl für Thermische Verfahrenstechnik (TVT)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2010
• 资助国家: 德国
• 起止时间: 2009-12-31 至 2016-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/175166909?language=en
• 关键词: Wetting; fouling; polymeric; films

Various polymer surfaces have been studied in the current project with regard to their wetting and scaling behavior. The impact of surface roughness and pre-treatment techniques (plasma/corona) have been quantified and can be used for estimation of an industrial application potential. The observed positive wetting characteristics of Ionic Liquids (IL) are an incentive for further investigations, because of the high potential in process intensification of e.g. absorption chillers with alternate working pairs (IL/water instead of LiBr/water). An increased wettability of the high viscous fluids results in enhanced heat transfer due to the formation of thin and stable liquid films. The simple contact angle measurements gave a profound basis to predict the performance of falling film wetting. Existing correlations for the critical liquid load of falling films (relevant for layout) on plane surfaces were successfully adapted to that of polymeric surfaces. The expected low scaling affinity of the polymeric surfaces could be quantified with stainless steel as benchmark. A relation between deposition quantity and surface free energy as well as adhesive force of the deposit was established. A demand for future investigations exists to verify the low scaling propensity of the polymer surfaces also for mixed salt solutions relevant for real industrial processes. A stepwise adaption of the experimental methodology to describe the complex mechanisms of mixed salt deposition on polymeric surfaces is planned within the time frame of the one year project extension. The improved wetting performance of the polymer surfaces due to conditioning could be explained by changes in polymer conformation, also validated by molecular dynamics simulation. It could be shown that coarse grained dissipative particle dynamics (DPD) simulations can be used to analyze the local conditions for wetting enhancement. However, in addition to the already obtained DPD interaction parameters of water and polymer an exemplary validation of the methodology using an alternative solvent (e.g. isopropanol as organic one) is still necessary.

在当前的项目中，已经研究了各种聚合物表面的润湿和结垢行为。表面粗糙度和预处理技术（等离子体/电晕）的影响已被量化，并可用于估计工业应用潜力。观察到的离子液体（IL）的正润湿特性是进一步研究的动力，因为例如具有交替工作对（IL/水而不是LiBr/水）的吸收式制冷机的过程强化的高潜力。由于形成薄且稳定的液体膜，高粘性流体的增加的润湿性导致增强的热传递。简单的接触角测量为预测降膜润湿性能提供了重要依据。现有的相关性的临界液体负荷的平面表面上的降膜（相关的布局）被成功地调整到聚合物表面。聚合物表面的预期低结垢亲和力可以用不锈钢作为基准来量化。建立了沉积量与存款表面自由能和附着力的关系。未来的研究需要验证聚合物表面的低结垢倾向，也适用于与真实的工业过程相关的混合盐溶液。一个逐步适应的实验方法来描述复杂的机制，混合盐沉积在聚合物表面的计划在一年的项目延长的时间框架内。由于调理的聚合物表面的润湿性能的改善可以通过聚合物构象的变化来解释，也通过分子动力学模拟来验证。结果表明，粗粒耗散粒子动力学（DPD）模拟可以用来分析润湿增强的局部条件。然而，除了已经获得的水和聚合物的DPD相互作用参数之外，仍然需要使用替代溶剂（例如，异丙醇作为有机溶剂）对方法进行示例性验证。