Materials World Network: Anomalous Thermoelasticity in Liquid Crystalline and Semicrystalline Polymer Networks

材料世界网络：液晶和半结晶聚合物网络中的反常热弹性

• 批准号: 0758631
• 负责人: Patrick Mather
• 金额: $ 32万
• 依托单位: Syracuse University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2007
• 资助国家: 美国
• 起止时间: 2007-09-01 至 2010-12-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0758631&HistoricalAwards=false
• 关键词: Materials; World; Network; Anomalous; Thermoelasticity

This Inter-American collaboration between the US and UNAM-Cuernavaca in Mexico addresses outstanding questions concerning reversible (two-way) shape memory behavior in ordered polymers, recently discovered by the investigators to exist for both liquid crystalline and semicrystalline networks. Reversible shape memory is the process whereby, under a small applied stress, specimens undergo heating-induced contraction and cooling-induced elongation a sequence that can be repeated indefinitely for conversion of heat to work. While the phenomenon is exciting, of great potential use in soft actuation devices, and possibly universal among ordered polymer networks, fundamental studies are required to elucidate underlying mechanisms of the behavior. Thus, the collaborating investigators have conceived combining materials synthesis and solid-rheological characterization (US) with detailed, in-situ, microstructural characterization (Mexico) that will lead to quantitative and mechanistic understanding that connects molecular architecture, molecular interactions, nanostructure, and thermo-mechanical response. Using modern experimental approaches, the investigator establish design principles that guide the development of new shape memory polymers and processing schemes alike. By adopting a comparative analysis approach among multiple materials systems, the researchers anticipate discernment of both universal thermoelastic mechanisms and system-specific behavior. The investigators further endeavor to exploit the two-way shape memory behavior in the form of inventive devices, including design, fabrication, and testing.The collaboration functions through significant exchange of undergraduate, graduate, and postdoctoral researchers between the US (Mather's lab) and Mexico (Romo-Uribe's lab), engendering broad technical and cultural education alike. Network materials will be synthesized in the US, while in-situ x-ray deformation studies on the materials will be conducted in Mexico. As an outreach activity, the investigators establish CyberSTRETCH, a system for remote instrument control that enhances the collaboration and offers the broad impact potential for remote access to elastomer tensile testing for middle school and high school science, physics, or chemistry classes, revealing concepts of materials, strength, and mechanical design.This award is co-funded with the NSF Office of International Science and Engineering.

美国和墨西哥的UNAM-CuerNavaca之间的这一美洲合作解决了关于有序聚合物中可逆(双向)形状记忆行为的悬而未决的问题，研究人员最近发现，有序聚合物中既存在液晶网络，也存在半晶体网络。可逆形状记忆是在较小的外加应力下，样品经历加热引起的收缩和冷却引起的伸长的过程，这一序列可以无限重复，以将热转换为功。虽然这种现象令人兴奋，在软驱动设备中具有巨大的潜在用途，而且可能在有序聚合物网络中普遍存在，但需要进行基础研究来阐明这种行为的潜在机制。因此，合作研究人员设想将材料合成和固体流变学表征(US)与详细的原位微结构表征(墨西哥)相结合，这将导致对分子结构、分子相互作用、纳米结构和热机械响应的定量和机械理解。利用现代实验方法，研究人员建立了指导新形状记忆聚合物和加工方案开发的设计原则。通过在多个材料系统之间采用比较分析方法，研究人员预计将同时识别通用的热弹性机制和系统特有的行为。研究人员进一步努力以创造性装置的形式开发双向形状记忆行为，包括设计、制造和测试。通过美国(Mather的实验室)和墨西哥(Romo-Uribe的实验室)之间大量的本科生、研究生和博士后研究人员的交流，产生了广泛的技术和文化教育，合作发挥了作用。网络材料将在美国合成，而材料的现场X射线变形研究将在墨西哥进行。作为一项外展活动，研究人员建立了CyberSTRETCH，这是一个远程仪器控制系统，它加强了合作，并为远程访问中学和高中科学、物理或化学课程的弹性体拉伸测试提供了广泛的影响潜力，揭示了材料、强度和机械设计的概念。该奖项由NSF国际科学与工程办公室共同资助。