Phase- and Interfacial Behavior of hyperbranched aqueous polymer solutions

具有树状结构的超支化聚合物是具有大量极性端基的强支化、多分散的大分子。根据它们的独特性质，讨论了它们在几个潜在的应用领域，如用于蒸馏、萃取或捕获二氧化碳的环境友好的溶剂，或作为药物输送系统在医药、食品技术和化妆品中的应用。对于所有这些目的，液-液平衡(LLE)以及界面性质都起着重要的作用。在上一个研究项目中，发展了一个基于晶格-簇合物理论(LCT)的新模型，该模型结合了两种不同的缔合模型来描述超支化聚合物水溶液的脱混行为。实验浊点曲线的模拟精度令人满意。第一种缔合模型将缔合描述为强物理相互作用(Wertheim理论)，第二种缔合模型描述为化学平衡(E-Calm)。两种缔合模型都能够解释在溶剂(通常是水)和聚合物的极性端基之间发生的交叉缔合以及溶剂和/或聚合物的自缔合。该组合模型允许在热力学方程中直接使用聚合物结构，而无需任何额外的可调整参数。然而，该模型在当前状态下最大的缺点是忽略了超支化聚合物的多分散性。因此，实际预定的研究项目旨在解决这一问题。首次用连续热力学方法研究了多分散性对分子质量的影响。除了相平衡之外，界面性质也是人们感兴趣的焦点。到目前为止，对于存在界面的非均质体系，利用密度梯度理论对界面性质的模拟仅限于三元体系。为了描述多分散聚合物在单一溶剂中的界面性质，这一理论应该得到推广。这一广义理论将使界面富集化的研究成为可能，特别是对于界面上优先富集长链聚合物还是短链聚合物的问题，将会得到解答。由于大分子聚合物的高粘度，这个问题的回答对材料在界面上的传递有很大的影响。建立了超支化聚合物水溶液的理论框架。此外，还将研究由超支化聚合物和醇(正丙醇和异丙醇)组成的溶液的热力学性质。利用这种方法，将详细地研究模型的可转移性。

Hyperbranched polymers with a tree-like structure are strongly branched, polydisperse macromolecules with a large number of polar terminal groups. Based on their unique properties several potential application areas, such as environment-friendly solvent for distillation, extraction or CO2-capture or as drug-delivery system in medicine, in food technology and in cosmetics are discussed. For all of these purposes the liquid-liquid equilibria (LLE) as well as the interfacial properties play an important role. In the last research project a new model based on Lattice-Cluster-Theory (LCT) in combination with two different association models for the description of the demixing behavior of aqueous hyperbranched polymer solutions was developed. The experimental cloud point curve could by modeled with satisfactory accuracy. The first association model describes the association as strong physical interaction (Wertheim theory) and the second one as chemical equilibrium (E-CALM). Both association models are able to account for cross association occurring between the solvent, usually water, and the polar terminal groups of the polymer and the self-association of the solvent and/or the polymer. The combined model allows the direct use of the polymer architecture in the thermodynamic equations without any additionally adjustable parameter. However, the most important disadvantage of the model in its current state is the negligence of the polydispersity of the hyperbranched polymer. Therefore, the actual scheduled research project aims to solve this issue. To the first time the influence of the polydispersity with respect to the molecular weight using continuous thermodynamics should by investigated theoretically. Beside to the phase equilibria also the interfacial properties are in focus of interest. Until now, the modeling of interfacial properties with help of the density gradient theory for inhomogeneous systems, where an interface is present, is limited to ternary systems. The theory should be generalizes in order to describe the interfacial properties of polydisperse polymers in a single solvent. This generalized theory will permit the study of interfacial enrichment, especially the question, if short-chain polymers or long-chain polymers will be preferential enriched in the interface will be answered. Caused by the high viscosity of polymers having a large molecular weight the answer of this question has a large impact on the material transfer over the interface. The theoretical frameworks will be developed for aqueous hyperbranched polymer solution. Additionally, the thermodynamic properties of solution composed of hyperbranched polymers and alcohol (1-propanol and 2-propanol) will be investigated. Using this approach the transferability of the models will be investigated in detail.