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

我们在SPP PiKo中的工作已经深入了解了纳米级颗粒接触的性质。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。我们还可以展示聚集体的大小如何决定聚集体的破碎力，并且能够解开纳米颗粒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，我们寻求通过两种方式扩大我们工作的影响。首先，我们将应用粒子团聚体的力响应的知识来预测在复杂的负载情况下的膜的行为，包括剪切应变，相关的技术应用。其次，我们将我们开发的粗粒（CG）粒子间的潜力到耗散粒子动力学（DPD）形式主义进行离散元模型（DEM）模拟复杂的负载下的大聚集体膜。我们的努力将针对优化的层压过程，使沉积高度多孔，FSP生产的纳米粒子薄膜上任意材料基板的装置在我们的小组开发的一种新型的层转移制造工艺。具体而言，我们将追求四个主要目标。(1)我们将重现实验测量的机械响应的整个颗粒膜在受控载荷条件下与新开发的粗粒度模型。从这些模拟中，我们将确定薄膜拓扑结构和其机械响应之间的关系。(2)我们将在预定义的条件下表征不同的负载响应（湿度、粒度分布、骨料尺寸等）。研究环境对这些力学关系的影响。(3)我们将通过不同的生产参数以可控和可预测的方式使用并行实验和模拟（过程建模）来修改层压薄膜的特性。(4)我们的目标是转移我们的知识DEM/CG建模开发这里和其他DEM/DPD建模方法采用其他SPP合作伙伴。此外，我们将与SPP合作伙伴合作，研究我们的知识对其他颗粒处理技术（如过滤）的适用性。

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.