Studies of Mixed Polymer Brushes Designed for Periodic In-Plane Order

为周期性面内顺序设计的混合聚合物刷的研究

• 批准号: 1506542
• 负责人: Christopher Ober
• 金额: $ 63.2万
• 依托单位: Cornell University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-06-01 至 2019-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1506542&HistoricalAwards=false
• 关键词: Studies; Mixed; Polymer; Brushes; Designed

PART 1: NON-TECHNICAL SUMMARY Polymers are valuable materials in everyday life. These long-chain molecules are the basis of industries ranging from food packaging to medical device manufacture to the clothing we wear. Polymers are critical components in the nanotechnology revolution enabling the manufacture of microelectronics that make possible smart phones. This project studies mixed polymer brushes, that is, more than one kind of polymer chain tied to a surface. Unique features of polymer brushes compared to other polymer systems are that they are bound to a surface, extended perpendicular to the surface, and have a controlled thickness and controlled surface chemistry. We will study how mixtures of two brushes phase separate, like oil and water, and form structures smaller than possible with today's advanced patterning methods. Over length scales of a few nanometers the nature of a surface can be transformed from a rigid inorganic structure to one that is soft and organic. Computer models predict symmetrical, periodic structures that we will explore as new nanostructures, as new energy storage materials and as new materials for biotechnology applications. We will work with computer experts to improve their theory and models by providing information about how well their concepts correctly predict these new mixed brush coatings. The research program will engage students in polymer science and materials research, foster globally aware graduate students and train students to work in a collaborative environment. Graduate students will in turn serve as mentors and role models to undergraduate students from Cornell and other universities, while gaining supervisory skills. REU students from other schools with an emphasis on underrepresented students will participate in research during the summer months. The PI and graduate student volunteers will interact with high school teachers in an RET program and teachers' workshops. PART 2: TECHNICAL SUMMARY This fundamental research program will investigate the synthesis, processing and characterization of mixed polymer brushes designed to form controlled periodic spacings in the plane of the brush film. By using mixed polymer brushes of coil-coil and rod-coil architectures and harnessing their in-plane phase separation we will create patterned structures with controlled topography, porosity or multipath transport properties. Mixed polymer brushes will be synthesized using living radical polymerization of flexible coil polymers and Kumada chemistry of conjugated rod polymers. The in-plane phase separation process of dense brushes with controlled brush uniformity will be investigated. Studies will make use of new binary brush initiators developed using Passerini chemistry to form coil-type homopolymer, diblock copolymer and multiblock copolymer mixed brushes. The phase behavior and how it compares to computational predictions will be studied for homopolymer and block copolymer pairs with the goal of creating stable periodic structures. Computational materials science through our collaborations will be used to guide brush design and selection, to predict physical structure and to aid examination of the physical properties of these new materials. To achieve our goal of uniform long-range order in these brush layers, we will investigate solvent vapor annealing and thermal transient laser spike annealing in conjunction with guiding structures. Characterization of the brushes will be made using a variety of analytical methods including X-ray reflectometry, grazing incidence (GI) SAXS and WAXS, neutron reflectivity and STORM superresolution fluorescence microscopy measurements. Charge transport measurements will be carried out on new rod-coil mixed brushes. Each technique will provide information about the internal or surface organization of the material and will aid our understanding of the structures produced.

第1部分：非技术摘要聚合物是日常生活中有价值的材料。这些长链分子是从食品包装到医疗设备制造再到我们穿的衣服的行业的基础。聚合物是纳米技术革命中的关键组成部分，从而实现了使智能手机可能的微电子制造的生产。该项目研究混合聚合物刷，即与表面绑定的多种聚合物链。与其他聚合物系统相比，聚合物刷的独特特征是它们与表面结合，垂直于表面延伸，并具有受控的厚度和受控的表面化学。我们将研究两种刷子的混合物如何分开，例如油和水，并使用当今的先进图案方法形成比可能的结构要小。在几个纳米的长度上，表面的性质可以从刚性无机结构转变为一种柔软和有机的结构。计算机模型可以预测我们将以新的纳米结构，新的储能材料和生物技术应用的新材料作为对称的周期性结构。 我们将与计算机专家合作，通过提供有关其概念正确预测这些新的混合刷涂层的信息，以改善其理论和模型。该研究计划将吸引学生参与聚合物科学和材料研究，培养全球意识的研究生，并培训学生在协作环境中工作。研究生又将成为康奈尔大学和其他大学的本科生的导师和榜样，同时获得监督技能。来自其他学校的REU学生强调代表性不足的学生将在夏季参加研究。 PI和研究生志愿者将在RET计划和教师讲习班中与高中老师互动。 第2部分：技术总结该基本研究计划将研究旨在在刷膜平面形成受控周期间距的混合聚合物刷的合成，加工和表征。通过使用线圈线和杆圈架构的混合聚合物刷并利用其平面相距，我们将创建具有受控地形，孔隙率或多径传输特性的图案化结构。混合聚合物刷将使用柔性线圈聚合物的生命自由基聚合和共轭杆聚合物的kumada化学合成。将研究具有受控刷均匀性的密集刷子的平面相分离过程。研究将利用使用Passerini化学形成线圈型均聚物，二嵌段共聚物和多嵌段共聚物混合刷的新的二元刷启动器。将研究均聚物和阻断共聚物对的相位行为及其与计算预测的比较，目的是创建稳定的周期性结构。计算材料科学通过我们的协作将用于指导刷子设计和选择，预测物理结构并帮助检查这些新材料的物理特性。为了在这些刷子层中实现均匀的远程顺序的目标，我们将研究溶剂蒸气退火和与引导结构结合使用的热瞬态激光尖峰退火。将使用多种分析方法进行刷子的表征，包括X射线反射量法，放牧发生率（GI）SAX和蜡，中子反射率和Storm超数荧光显微镜测量。电荷运输测量将在新的杆圈混合刷上进行。每种技术都将提供有关材料内部或表面组织的信息，并有助于我们对生成的结构的理解。