SGER: Particles to Control Structure and Dynamics of Multiphase Polymers

摘要CTS-0431349 S。Velankar，University of EscherichburghSGER：粒子控制多相聚合物的结构和动力学概念：如果粒子被添加到两种不混溶液体的系统中，它们倾向于位于两种液体之间的界面处，并降低不混溶液体之间的界面张力。 这些特征使人联想到表面活性剂，即颗粒可以表现得像表面活性剂，即使它们不是两亲性的。 这一建议的假设是，这种界面活性颗粒可以用来控制两相聚合物共混物的形态。动机：不混溶聚合物通常以熔融状态共混在一起以获得具有单一均聚物不可行的性质的材料。 许多所需的性能要求共混物具有特定的微观结构，例如，导电共混物可以通过将少量导电均聚物共混到绝缘材料中来实现，只要导电均聚物是连续相。 因此，控制由两相共混操作产生的形态的能力是至关重要的。 该项目的成功将为控制两相形貌提供一种全新的方法。研究建议：在过去的研究中，颗粒在界面上直接沉积在扩散溶剂中。 这种直接在界面沉积颗粒的方法不适用于聚合物共混物应用。 因此，本项目的第一个目标是设计一种机械混合程序，将颗粒输送到界面，并允许它们吸附在那里。 第二个目标是量化两相结构中任何位置处界面处的颗粒浓度、相应的界面张力和颗粒在界面处的接触角。 最终目标是证明两相流的动力学以及由此产生的形态确实可以通过使用颗粒来改变。 总体目标是建立上述假设的原理证明，并为更详细的研究两相结构的粒子控制奠定基础。优点：虽然颗粒通常用于改性均聚物的本体性质，但该提议试图将颗粒专门用作表面活性剂。 它提供了一个全新的方法来控制聚合物共混物的形态。 目前，用于聚合物的唯一常用的表面活性剂是嵌段共聚物。 这些通常是系统特定的;给定的嵌段共聚物仅对少数均聚物对具有表面活性。 颗粒的一个显著优点是它们是非特异性的，并且可以用于更广泛的共混物中。这项研究将补充PI实验室对多相流的其他研究。 它将培训一名研究生和一名本科生进行聚合物的实验研究。 作为该项目的一部分，对毛细管不稳定性的研究与分散混合、喷墨打印等各种应用有关，因此其本身很重要。PI在这里所涵盖的研究主题中拥有广泛的知识和实验技能。 所有必要的实验资源都是可用的，或者将在本研究期间采购或制造。

AbstractCTS-0431349S. Velankar, University of PittsburghSGER: Particles to control structure and dynamics of multiphase polymers Concept: If particles are added to a system of two immiscible liquids, they tend to locate at the interface between the two liquids and decrease of the interfacial tension between the immiscible liquids. These characteristics are reminiscent of surfactants i.e. particles can behave like surfactants even though they are not amphiphilic. The hypothesis of this proposal is that such interfacially active particles can be employed to control the morphology of two-phase polymer blends. Motivation: Immiscible polymers are commonly blended together in the melt state to achieve materials with properties not feasible with single homopolymers. Many of the desired properties require the blend to have a specific microstructure e.g. a conductive blend may be realized by blending a small amount of conductive homopolymer into an insulating one provided the conductive homopolymer is the continuous phase. An ability to control the morphology resulting from two-phase blending operations is therefore critical. Success of this project will provide an entirely new method to control two-phase morphologies. Research Proposal: In past research on particles at interfaces, particles were deposited directly at the interface in a spreading solvent. This procedure of depositing particles directly at the interface is unsuitable for polymer blend applications. The first goal of this project therefore is to devise a mechanical blending procedure that will deliver particles to the interface and allow them to adsorb there. The second goal is to quantify the concentration of particles at the interface at any location in the two-phase structure, the corresponding interfacial tension, and the contact angle of the particles at the interface. The final goal is to demonstrate that the dynamics of two-phase flows, and the morphology resulting from them, can indeed by modified using particles. The overall objective is to establish proof-of-principle of the hypothesis above, and lay the ground for more detailed research on two-phase structure control with particles. Merits: While particles are commonly used to modify the bulk properties of homopolymers, this proposal attempts to exploit particles specifically as surface-active agents. It offers a radically new approach to controlling the morphology of polymer blends. At present, the only common surface-active agents for polymers are block copolymers. These are generally system-specific; a given block copolymer is surface-active for only a few homopolymer pairs. A significant advantage of particles is that they are non-specific and may be used in a wider range of blends. This research will complement other research on multiphase flow in the PI's lab. It will train one graduate and one undergraduate student on experimental research in polymers. The research on capillary instabilities to be conducted as a part of this project is relevant to a variety of applications such as dispersive mixing, inkjet printing, etc. and thus important in its own right. The PI has extensive knowledge and experimental skills in the research topics covered here. All the necessary experimental resources are either available, or will be procured or fabricated during this research.