Adhesion Mechanisms and Nanomechanics of the Contact Interfaces between TiO2 Nanoparticles in Films and Aggregates - Phase 3

我们在SPP PiKo的工作已经取得了进展，深入了解了纳米尺度上粒子接触的本质。通过分子动力学模拟和AFM力谱实验的结合，我们可以证明纳米颗粒的接触行为与非连续介质效应有关，其中吸附水的分子结构起着关键作用。我们还可以展示团聚体大小如何决定团聚体的破碎力，并能够揭示在纳米颗粒薄膜的机械加载过程中滚动和滑动事件的不同贡献。在SPP的第三阶段，我们力求从两个方面扩大我们工作的影响。首先，我们将应用颗粒团块的力响应知识来预测薄膜在复杂加载场景下的行为，包括与技术应用相关的剪切应变。其次，我们将把我们开发的粗粒度（CG）粒子间势导出到耗散粒子动力学（DPD）形式中，以执行复杂载荷下大聚集体膜的离散元素建模（DEM）模拟。我们的努力将指向层压工艺的优化，通过我们小组开发的一种新的层转移制造工艺，可以在任意材料衬底上沉积高多孔的、fsp生产的纳米颗粒薄膜。具体来说，我们将追求四个主要目标。(1)我们将用新开发的粗粒度模型再现受控加载条件下实验测量的全颗粒膜的力学响应。从这些模拟中，我们将确定薄膜拓扑结构与其机械响应之间的关系。(2)我们将在预定义的条件下（湿度、粒度分布、骨料粒度等）表征不同的加载响应，以研究环境对这些力学关系的影响。(3)我们将通过并行实验和模拟（过程建模），在可控和可预测的方式下，通过不同的生产参数来改变层压膜的性能。(4)我们的目标是转移我们在这里开发的DEM/ cg建模和其他SPP合作伙伴使用的其他DEM/DPD建模方法的知识。此外，我们的知识适用于其他颗粒处理技术，如过滤，将与SPP合作伙伴合作研究。

Our work within the SPP PiKo has progressed to a deep understanding of the nature of the particle contacts at the nanoscale. By means of a combination of Molecular Dynamics simulations and AFM force spectroscopy experiments we could demonstrate that the contact behavior of nanoparticles is related to non-continuum effects where the molecular structure of adsorbed water plays a key role. We could also show how the aggregate size determines the breakage force of agglomerates and were able to unravel the different contributions of rolling and sliding events during the mechanical loading of nanoparticle films. In the third phase of the SPP we seek to broaden the impact of our work in two ways. First, we will apply the knowledge of the force-response of particle agglomerates to predict the behavior of films under complex loading scenarios, including shear strain, relevant to technological applications. Second, we will export our developed coarse-grained (CG) interparticle potentials into Dissipative Particle Dynamics (DPD) formalisms to perform Discrete Element Modelling (DEM) simulations of large aggregate films under complex loading. Our efforts will be directed towards the optimization of a lamination process that enables the deposition of highly porous, FSP-produced nanoparticle films on arbitrary materials substrates by means of a novel layer transfer fabrication process developed in our group. Specifically, we will pursue four main objectives. (1) We will reproduce the experimentally measured mechanical response of whole particle films under controlled loading conditions with newly developed coarse-grained models. From these simulations we will determine the relationships between the film topology and its mechanical response. (2) We will characterize different loading responses under predefined conditions (humidity, particle size distribution, aggregate size, etc.) to investigate the influence of the environment on these mechanical relationships. (3) We will modify the properties of laminated films through different production parameters in a controlled and predictable way using experiments and simulations in parallel (Process Modelling). (4) We aim to transfer our knowledge of the DEM/CG-modelling developed here and other DEM/DPD modelling approaches employed by other SPP partners. Moreover, the applicability of our knowledge to other particle handling technology, such as filtration, will be studied in cooperation with SPP partners.