Controlled Surfaces through Self-assembly and Patterning

拟议的研究旨在加深对如何利用含氟聚合物的自组装形成周期性的纳米级聚合物结构的基本理解，这些结构由各种热和光学方法控制。在拟议的研究中，我们将合成并研究半氟化(SF)液晶线圈嵌段共聚物的表面和本体性质，其中SF基团I是单枝形的。表面将使用各种技术进行探测，但特别是扫描力显微镜(SFM)和近边X射线吸收精细结构(NEXAFS)测量将用于检查表面形貌和成分。拟议研究的一个特别重点来自我们最近的观察，即带有SF单枝侧基的聚合物不仅能够形成低能量表面，而且可以自发地组织成具有20 nm长度尺度的周期性组织的阵列，该阵列可以跨越接近毫米尺寸的区域。为了检验预测表面曲率的模型，将根据选定的烷基与氟化链段比例、臂数和端基来生成SF单枝晶。光活性偶氮苯基团也将用于单枝晶的合成，以改变堆积结构和利用其光学性质。通过结合已知的偶氮苯发色团的反式-顺式异构化行为，我们还计划使用光处理来指导这些表面结构的远程组织。在生产纳米技术所需的小规模图案时，没有在10到50 nm长度范围内构建结构或修改表面的方便工艺。在微米尺度上看起来均匀的结构在这些较小的维度上可能是非常不均匀的，因此使得表面能和成分的控制等问题变得极其重要。氟聚合物是在表面和界面设计中探索其中许多因素的理想材料。氟聚合物的低表面能使其在防止蛋白质与生物医学表面结合、作为环境友好的耐污染海洋涂料和自清洁建筑材料等方面的应用引起了人们的兴趣。氟聚合物在短光波长下的不同寻常的透明度使其成为微电子制造的下一代光致抗蚀剂，而它们的低介电常数和折射率使其在微电子和通信领域得到了广泛的应用。该程序将利用自填充图案表面。如果能够在控制表面成分的同时利用这种长度尺度的图案，那么在生物技术、信息科学和先进材料中应用的可能性是巨大的。

The proposed studies are aimed at developing a fundamental understanding of the way in which the self-assembly of fluoropolymers can be harnessed to form periodic nm-length scale polymer structures, controlled by a variety of thermal and optical methods. In the proposed research we will synthesize and study the surface and bulk properties of semifluorinated (SF) LC-coil block copolymers in which the SF group I a monodendron. The surface will be probed with a variety of techniques, but in particular scanning force microscopy (SFM) and near edge X-ray absorption fine structure (NEXAFS) measurements will be used to examine surface topography and composition. A particular focus of the proposed research derives from our recent observation that polymers with SF monodendron side groups are capable of forming not only low energy surfaces, but may spontaneously organize into arrays with periodic organization on the 20 nm length scale that can span regions approaching millimeter dimensions. The SF monodendrons will be produced with selected alkyl to fluorinated segment ratios, arm number and end group in order to test the model predicting surface curvature. A photoactive azobenzene group will also be used in mondendron synthesis to both alter the packing structure and take advantage of its photo-optical properties. By combining the known trans-cis isomerization behavior of the azobenzene chromophore, we also plan to use photoprocessing to direct long-range organization of these surface structures. In the production of small-scale patterns needed for nanotechnology, there is no convenient process for building structures or modifying surfaces in the 10 to 50 nm length regimes. Structures that appear homogeneous over micron length scales can be extremely heterogeneous at these smaller dimensions, thus making issues such as the control of surface energy and composition extremely important. Fluoropolymers are ideal materials for exploring many of these factors in surface and interface design. The low surface energy of fluoropolymers has attracted interest in such diverse surface control applications as the prevention of protein binding to biomedical surfaces, as environmentally friendly fouling resistant marine coatings and for self-cleaning architectural materials.The unusual transparency of fluoropolymers at short optical wavelengths has lead to their study as next generation photoresists for microelectronics manufacture while their low dielectric constant and refractive index has made their use in microelectronics and communications widespread. This program will harness self-pattern surfaces. There exist immense possibilities for applications in biotechnology, information science and advanced materials if patterning at these length scales can be harnessed while simultaneously controlling surface composition.