Forming functional surfaces through surface-anchored macromolecular networks

非技术总结具有功能性和可定制表面特性的材料的设计和制造是当前材料研究面临的最重要挑战之一。 要找到一种能够独立控制化学组成、表面形貌、官能团的迁移率、机械性能和电荷的材料是令人生畏的。 聚合物涂层包含通过附着于表面的所谓交联点在各个位置连接的大分子，可能符合要求。 阻碍这类材料广泛应用的主要障碍是需要化学合成特种聚合物。 该项目通过使用一系列简单的交联剂分子将各种聚合物转化为表面锚定的交联聚合物涂层来克服这一限制，所述交联剂分子是市售的或非常容易合成的。 因此，任何人都可以利用所提出的方法结合各种起始材料来制造具有受控组成、柔软度、表面形貌和其他重要物理化学特性的功能表面。 导致形成这种表面的方法已经被设计成高度可扩展的，使得它们原则上可以应用于涂覆大面积表面。 该研究项目也将有助于高中，本科和研究生的科学和工程教育。 这些包括科学培训和交流、演讲技巧以及科学和技术方面的道德原则。 将在当地场地（研究三角区的高中和大学）以及弗吉尼亚州阿拉拉特的小学（位于我国最偏远的地区之一）开展外联活动。 将鼓励当地K-12学生和教师通过个人辅导和北卡罗来纳州科学之家组织的项目参与研究/教育活动。 目前的努力和未来的计划，为组织科学和推广会议，工业界和一般公众在研究三角region. Technical总结这个项目的中心目标是创造功能表面附着聚合物网络膜具有高度可剪裁的特点到固体基板。 这些聚合物网络包括长链分子的阵列（即，大分子）在几个节点处相互连接（即，交联点）。 通过使用配备有两个官能团A和B的小官能分子（SFM）交联大分子来产生聚合物网络，其中A与相邻聚合物链形成化学键，并且来自两个相邻SFM（或/和基底）的B基团形成化学键或物理键，这取决于B单元的性质。 这种方法使任何聚合物，无论其功能，适合化学交联和固定在表面上。 重要的是，SFM可商购获得或可以容易地合成。 直接的科学和技术影响在于提供了一个来源不可知的框架，以设计和生产具有受控化学成分、调谐（和可擦除）拓扑结构、可定制的柔软度和摩擦力以及其他相关物理化学界面特性的表面。 网络形成过程的简单性和可调性使其成为科学家和工程师的理想选择，而无需高度的化学专业知识，并将其范围扩大到生物医学和医疗保健科学，安全或国防。 项目说明概述了旨在测试拟议的网络生成假设和建立结构-过程特性的任务。 具体而言，网络形成的结构和动力学将建立一系列不同的SFM，不同的退火时间，和退火温度。 通过将磁响应纳米颗粒掺入SFM中，将产生响应于外部磁场而改变形貌的机械性能的功能聚合物网络涂层。 所提出的努力还概述了形成以水凝胶为特征的双层的新方法（即，在水中溶胀的聚合物网络）和硅氧烷弹性体（即，不需要溶剂来保持柔性的柔性橡胶）。 这些层压材料经常用于生物医学，形状变化和可变形材料，但它们的制备目前依赖于弹性体组分的苛刻物理处理。 该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

NON-TECHNICAL SUMMARYThe design and fabrication of materials with functional and tailorable surface properties represents one of the most important challenges facing current materials research. It is daunting to identify a material that enables independent control of chemical composition, surface topography, mobility of functional groups, mechanical properties, and charge. Polymer coatings comprising macromolecules linked at various locations via so-called crosslink points attached to surfaces may fit the bill. A major obstacle that has hindered widespread application of such materials is the need for chemical synthesis of specialty polymers. This project overcomes this limitation by turning a wide variety of polymers into surface-anchored crosslinked polymer coatings using a family of simple crosslinker molecules that are either commercially available or are very easy to synthesize. Thus, anyone can utilize the proposed method in combination with a variety of starting materials to fabricate functional surfaces with controlled composition, softness, surface topography, and other important physico-chemical characteristics. The processes leading to the formation of such surfaces have been designed to be highly scalable, so that they could be, in principle, applied to coat large-area surfaces. This research project will also contribute to education of high school, undergraduate, and graduate students in science and engineering. These involve scientific training and communication, presentation skills, as well as ethical principles in science and technology. Outreach activities in both local venues (high schools and colleges in the Research Triangle area) as well as at elementary school in Ararat, VA (located in one of the most rural areas of our country) will take place. Local K-12 students and teachers will be encouraged to participate in the research/educational activities through individual mentoring and via programs organized by NC State's Science House. Current efforts and future plans for organizing scientific and outreach meetings for academe, industry, and general public in the Research Triangle region are included.TECHNICAL SUMMARYThe central goal of this project is to create functional surfaces by attaching polymer network films with highly tailorable characteristics onto solid substrates. These polymer networks comprise arrays of long chain molecules (i.e., macromolecules) connected mutually at several nodes (i.e., crosslink points). The polymer networks are generated by crosslinking macromolecules using small functional molecules (SFMs) equipped with two functional groups, A and B, wherein A forms a chemical bond with a neighboring polymer chain, and B groups from two neighboring SFMs (or/and the substrate) form either a chemical or a physical bond, depending on the nature of the B units. This method makes any polymer, regardless of its functionality, amenable to chemical crosslinking and immobilization on surfaces. Importantly, the SFMs are either available commercially or can be readily synthesized. The immediate scientific and technological impact lies in providing a source-agnostic framework to design and produce surfaces with controlled chemical composition, tuned (and erasable) topology, tailorable softness and friction, and other relevant physico-chemical interfacial characteristics. The simplicity and tunablity of the network-forming process makes it ideal for scientists and engineers without requiring high chemical expertise, and broadens its scope to biomedical and healthcare sciences, security, or national defense. The project description outlines tasks that aim at testing the proposed hypothesis of network generation and establishing structure-process properties. Specifically, the structure and kinetics of network formation will be established for a series of different SFMs, different annealing times, and annealing temperatures. Functional polymer network coatings that alter mechanical properties of topography in response to external magnetic fields will be generated by incorporating magnetically-responsive nanoparticles into the SFMs. The proposed effort also outlines new ways of forming bilayers featuring hydrogels (i.e., polymer networks that swell in water) and silicone elastomers (i.e., flexible rubbers that do not require solvent to remain flexible). These laminates are frequently used in biomedical, shape-changing, and deformable materials, yet their preparation currently relies on harsh physical treatment of the elastomer component. The proposed methodology removes this limitation and enables novel, cleaner, and reproducible manufacturing of these important composite materials.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.