Seeing how polymer chains organise with torsional tapping atomic force microscopy

通过扭转攻丝原子力显微镜观察聚合物链如何组织

• 批准号: EP/J013005/1
• 负责人: Jamie Hobbs
• 金额: $ 40.3万
• 依托单位: University of Sheffield
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2012
• 资助国家: 英国
• 起止时间: 2012 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FJ013005%2F1
• 关键词: Seeing; how; polymer; chains; organise

Our understanding of semicrystalline polymers, the class of polymers that by far and away dominates usage in modern society, is surprisingly poor. At a molecular scale we rely on cartoons and inference, unable to reach the certainty obtained in other areas of material science by direct, atomic or molecular scale imaging, and by diffraction from macroscopic crystals. Yet in polymers the structure at this level is arguably more important as it determines the properties from mechanical behaviour to the oxygen barrier performance through the adhesive behaviour to the aesthetic appeal. Recently we developed a new form of atomic force microscopy, torsional tapping AFM (TTAFM) capable of robustly and routinely obtaining images with true molecular resolution on the most frequently used polymers (polyolefins, that include polyethylene and polypropylene) in essentially any sample. This step change in performance is based on the improved dynamics and signal-to-noise performance that comes from the cantilever geometry and drive mechanism. Perfecting the cantilever design is predicted to lead to even greater performance, and to allow the technique to be used in a wide range of instruments. At the same time as developing the technology we will use it to answer a string of questions that underpin our understanding of polymer crystals, questions that will lead to both greatly enhanced fundamental understanding and real application from the development of new materials and applications to problem solving during processing. We aim to directly reveal how crystallization temperature, variations in chain chemistry, chain branching, re-enforcing fibres and particles, control the organisation of polymer chains within the crystal and at the interface between the crystal and the non-crystalline material. While doing this we will perfect the sample preparation methods for molecular scale imaging, and enhance the cantilever design to improve performance, allowing the technique to be widely adopted both in polymer science and across molecular nanoscience.

我们对半晶聚合物的了解出人意料地差，半晶聚合物是目前在现代社会中占主导地位的一类聚合物。在分子尺度上，我们依赖于卡通和推理，无法达到在材料科学的其他领域通过直接、原子或分子尺度成像以及通过宏观晶体的衍射获得的确定性。然而，在聚合物中，这一层次的结构可以说是更重要的，因为它决定了从机械性能到氧气阻隔性能，再到粘附性和美观性的各种特性。最近，我们开发了一种新形式的原子力显微镜，扭转攻丝AFM(TTAFM)，能够稳健和常规地获得几乎任何样品中最常用的聚合物(聚烯烃，包括聚乙烯和聚丙烯)的真实分子分辨率的图像。性能的这一步变化是基于改进的动力学和信噪比性能，这些性能来自悬臂几何结构和驱动机构。据预测，完善的悬臂设计将带来更好的性能，并允许该技术在各种仪器中使用。在开发这项技术的同时，我们将用它来回答一系列问题，这些问题巩固了我们对聚合物晶体的理解，这些问题将极大地提高基本理解和实际应用，从新材料和应用的开发到加工过程中的问题解决。我们的目标是直接揭示结晶温度、链化学变化、链分支、重新增强纤维和颗粒，如何控制晶体内以及晶体和非晶体材料之间的高分子链的组织。在此过程中，我们将完善分子尺度成像的样品制备方法，并加强悬臂设计以提高性能，使该技术在聚合物科学和跨分子纳米科学中得到广泛应用。