Collaborative Research: Liquid Crystal-Templated Chemical Vapor Polymerization of Complex Nanofiber Networks

合作研究：复杂纳米纤维网络的液晶模板化学气相聚合

• 批准号: 2322899
• 负责人: Nicholas Abbott
• 金额: $ 40万
• 依托单位: Cornell University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-03-01 至 2027-02-28
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2322899&HistoricalAwards=false
• 关键词: Collaborative; Research; Liquid; Crystal; Templated

Research supported by this grant generates foundational knowledge needed to develop new manufacturing processes for novel polymer films, advancing both science and technology and impacting national prosperity. Chemical vapor polymerization is a process where gas phase chemical species are reacted on surfaces to create thin polymer films. Although chemical vapor polymerization has been widely adopted by industry to create polymer coatings, e.g., for the microelectronics industry, the polymer coatings have been limited to flat films. This award supports fundamental research needed to expand the capabilities of chemical vapor polymerization to large-scale manufacturing of surface coatings with tailored nanoscopic structures, including end-attached nanofiber arrays or “nanograsses”, quasi-two-dimensional networks of interconnected nanofibers or “nanosheets”, and rigid end-attached nanofibers or “bed-of-nanonails”. Potential applications for this next generation of nanostructured coatings include improved adhesives, biomedical sensors, biomaterials for growing replacement organs, and water filtration membranes. This collaborative project provides an outstanding context for the multidisciplinary training of graduate students in next-generation manufacturing processes. The project also integrates an initiative that is focused on the engagement of veteran students in advanced manufacturing research. The scientific approach underlying this project is based on a convergence of ideas from two largely disconnected fields – liquid crystals and chemical vapor polymerization. Specifically, thin films of liquid crystals supported on surfaces are used as dynamic molecular templates to guide the formation of polymeric nanostructures via chemical vapor polymerization. The latter process is achieved by thermal sublimation and pyrolysis of paracyclophanes, which subsequently polymerize into shape-controlled nanostructures templated by the liquid crystal films. The research elucidates the chemical and physical processes that control the formation of newly discovered polymeric morphologies, e.g., nanofiber sheets, that can be accessed at scale by chemical vapor polymerization into liquid crystal films. Fundamental questions regarding the role of topological defects in liquid crystal-templated chemical vapor polymerization are investigated by using multiphase liquid crystal films containing dispersions of microparticles and immiscible oil droplets. Post-synthesis processes are also explored as an approach to achieving an expanded palette of nanostructures and functional properties, e.g., the synthesis of electrically conductive and morphologically tunable nanofiber arrays prepared via post-deposition pyrolysis. Other key aspects of the research revolve around the manufacturing of functional thin films with emergent photoluminescent, electrical, and transport properties. A unifying fundamental challenge underlying the approach is understanding how the information encoded in the atomic-scale structure, e.g., chirality, of reactive monomers is amplified across spatial scales by the liquid crystal during chemical vapor polymerization.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.

该资助支持的研究产生了开发新型聚合物薄膜的新制造工艺所需的基础知识，推动了科学技术的发展并影响了国家的繁荣。化学气相聚合是一种气相化学物质在表面发生反应以形成聚合物薄膜的过程。尽管化学气相聚合已被工业界广泛采用来制造聚合物涂层，例如用于微电子行业，但聚合物涂层仅限于平面薄膜。该奖项支持将化学气相聚合的能力扩展到大规模所需的基础研究。制造具有定制纳米结构的表面涂层，包括末端附着的纳米纤维阵列或“纳米草”、互连纳米纤维或“纳米片”的准二维网络，以及刚性末端附着的纳米纤维或“纳米指甲床”的潜在应用。下一代纳米结构涂层包括改进的粘合剂、生物医学传感器、用于生长替代器官的生物材料和水过滤膜。该项目还整合了一项旨在让资深学生参与先进制造研究的举措，该项目的科学方法基于两个基本互不相关的想法的融合。在液晶和化学气相聚合领域，表面支撑的液晶薄膜被用作动态分子模板，通过化学特别是气相聚合来引导聚合物纳米结构的形成，后者是通过热升华和热解来实现的。对环芳烷，随后聚合成以液晶薄膜为模板的形状控制的纳米结构，该研究阐明了控制新发现的聚合物形态形成的化学和物理过程，例如可以通过化学气相聚合大规模获得的纳米纤维片。通过使用含有微粒分散体的多相液晶薄膜，研究了有关液晶模板化学气相聚合中拓扑缺陷的作用的基本问题。不混溶的油滴也被探索作为实现纳米结构和功能特性的扩展调色板的方法，例如，通过后沉积热解制备的导电和形态可调的纳米纤维阵列的合成。围绕具有新兴光致发光、电学和传输特性的功能薄膜的制造，该方法背后的一个统一的基本挑战是理解信息如何编码在薄膜中。反应性单体的原子级结构（例如手性）在化学气相聚合过程中被液晶在空间尺度上放大。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查进行评估，被认为值得支持标准。