Near surface dynamics of layers of non-cross-linked and cross-linked polymer architectures at solid planar surfaces

提出的项目解决了不同分子结构的聚合物基质在固体平面基底存在下的内部动力学。用聚合物薄膜涂覆固体表面，使其功能化，对药物释放控制、润滑和感觉等方面有很大的影响。为了设计新的涂层，内部结构和动力学知识是必不可少的。这提供了一个更深入的了解聚合物链本身之间的相互作用，在交联的影响下，与添加剂，如混合系统（药物释放，感受器）或与其他表面（润滑）。虽然许多这些聚合物系统的结构已经被广泛研究，但对它们附着在表面时的动力学知之甚少，而拟议的项目将有助于缩小这一知识差距。该项目着重于几何约束对薄膜中聚合物动力学的影响，无论是靠近一个固体界面还是在两个固体界面之间。将研究在硅表面制备的两种不同聚合物结构：聚合物刷、交联聚合物刷、薄水凝胶层和吸附微凝胶颗粒。所有类型都将用刺激响应聚合物制备，除了交联剂外，化学成分将是相同的。垂直于围合表面的不同聚合物结构内的动力学剖面将由掠入射中子自旋回波光谱（GINSES）确定。因此，在接近固体界面的溶剂中，聚合物结构的链动力学和集体动力学将得到更好的理解。为了探讨动力学、结构和力学性能之间的关系，将动力学结果与结构（中子、x射线反射、SANS、GISANS、光散射、AFM、椭圆偏振）和粘弹性（AFM压痕、QCM-D）实验联系起来。在相对表面和刷的情况下，使用中子散射技术进行直接的原位和非接触研究将深入了解流体动力学以及不同分离距离下压缩和相互渗透对链和集体动力学的影响。刚性界面对聚合物动力学和力学的影响将作为尺寸参数和组成（交联剂和共聚单体含量）的函数进行研究。拟议的项目将受益于柏林工业大学和JCNS@MLZ两个小组的专业知识的强大协同作用。共同的专业知识包括合成、样品制备、多种技术的技术知识、散射技术的扩展（如ginss）和数据分析。该项目是为柏林工业大学的博士生设计的，预计在柏林工业大学学习三年，并在加尔兴的Maier-Leibnitz中心的JCNS站工作两年。

The proposed project addresses the inner dynamics of polymer matrices of different molecular architecture in the presence of solid planar substrate. Functionalisation of solid surfaces by coating them with thin polymer films has a large impact for e.g. controlled drug release, lubrication and sensorics. In order to design new coatings knowledge about the internal structure and dynamics is essential. This offers a deeper understanding of the interaction between the polymer chains themselves, under the influence of cross-linking, with additive like in hybrid systems (drug release, sensorics) or with other surfaces (lubrication). While the structure of many of these polymer systems has been already extensively studied not much is known about their dynamics when attached to surfaces, and the proposed project will contribute to close this gap of knowledge. The project focuses on the effect of geometrical confinement on the dynamics of polymer in thin films either close to one solid interface or between two solid interfaces. Two different polymer architectures prepared on Silicon surfaces will be investigated: polymer brushes, cross-linked polymer brushes, thin hydrogel layers and adsorbed microgel particles. All types will be prepared with stimuli responsive polymers and apart from the cross-linkers the chemical composition will be the same. Dynamics profiles within different polymer architectures perpendicular to the confining surface will be determined by grazing incidence neutron spin echo spectroscopy (GINSES). Thereby, a better understanding of chain dynamics and collective dynamics of polymer architectures in a solvent close to a solid interface will be achieved. To explore the relation between dynamics, structure and mechanical properties results on the dynamics will be linked to experiments on the structure (neutron-, x-ray reflectometry, SANS, GISANS, light scattering, AFM, ellipsometry) and viscoelastic properties (AFM indentation, QCM-D). In the case of opposing surfaces and brushes a direct in-situ and contactless investigation using neutron scattering techniques will gain insight into the hydrodynamics and effects of compression and interpenetration on the chain and collective dynamics at different separation distances. The influence of rigid interfaces on the polymer dynamics and mechanics will be studied as a function of size parameters and composition (cross-linker and comonomer content).The proposed project will benefit from the strong synergy of expertise of the two groups from TU Berlin and from JCNS@MLZ. The common expertise includes synthesis, sample preparation, technical knowledge over a large variety of techniques, extension of scattering techniques (e.g. GINSES) and data analysis. The project is designed for a PhD student with an anticipated time of three years located at the TU Berlin and a Post-doc position of two years located at the JCNS outstation at the Maier-Leibnitz Zentrum in Garching.