Chemomechanics: a bridge across the formidable gap

化学力学：跨越巨大鸿沟的桥梁

• 批准号: EP/L000075/1
• 负责人: Roman Boulatov
• 金额: $ 125.57万
• 依托单位: University of Liverpool
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2013
• 资助国家: 英国
• 起止时间: 2013 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FL000075%2F1
• 关键词: Chemomechanics; bridge; across; formidable; gap

The overarching objective of this proposal is to validate experimentally and bring to a new level of utility a conceptual framework for understanding and exploiting the chemical response of polymeric materials to mechanical loads. The enormous technological importance of polymeric materials is due largely to the remarkable range of their mechanical properties, i.e., their responses to mechanical loads. At the macroscopic scale such loads (stresses) change bulk shapes of objects, but the material response extends across many orders of magnitude in length and time. Almost as soon as the nature of polymers had been recognized certain simple manipulations of polymer solids, melts or solutions were shown to result in fragmentation of polymer backbones without the high temperatures that are normally required for strong covalent bonds to break at detectable rates. The effect is often called mechanochemistry. Mechanochemistry is thought to be important in controlling (1) crack propagation and catastrophic materials failure, (2) stability of surface-anchored polymers in microfluidic diagnostics and high-performance chromatography and (3) behavior of desalination membranes, impact-resistant materials (e.g., bulletproof vests) and tires; and in affecting technological processes as diverse as (4) jet injection (e.g., during inkjet material deposition in organic electronics), (5) polymer melt processing, (6) high-performance lubrication, (7) enhanced oil recovery (e.g., polymer flooding), (8) turbulence drag reduction (e.g., in pipelines, fire fighting, irrigation). Exploiting coupling between localized reactivity and mechanical loads could both advance these technologies and yield fundamentally new materials and processes, including polymer photoactuation (i.e., direct conversion of light into motion to power autonomous nanomechanical devices, control information flow in optical computing, position mirrors or photovoltaic cells in solar capture schemes), efficient capture of waste mechanical energy, materials capable of autonomous reporting of internal stresses and self-healing and tools to study polymer dynamics at sub-nm scales. To realize this remarkable potential fully the materials science community needs a set of theoretical, computational, synthetic and physicochemical tools and models to guide our effort to identify chemical compositions and molecular structures of monomers and polymer architectures that yield bulk materials with desired stress-responsive characteristics and to enable molecular studies of polymer dynamics particularly at the 5-100 nm lengthscale (the so called "formidable gap"). Achieving this goal requires a general, quantitative understanding of the relationship between the macroscopic parameters that define mechanical loads (e.g., stress or strain tensors) and the molecular properties that govern the changes in chemical reactivity (e.g., energies of activation). EPSRC funding will enable us to develop such understanding with a program that integrates (macro)molecular design and synthesis, physical measurements (using a variety of modern spectroscopic techniques, including single-molecule force spectroscopy and high-resolution X-ray photoelectron spectroscopy), instrument design, quantum-chemical computations, statistical-mechanics and finite-element modeling and theory. To accomplish this overall objective we will use a series of reactive monomers specifically designed for efficient and accurate kinetic measurements of localized reactivity and molecular interpretation of the results across the whole range of physical systems whose behavior is governed by dynamics of stretched macromolecules. These systems range from individual isolated stretched polymer chains all the way to bulk amorphous polymers under load.

本提案的总体目标是通过实验验证，并将理解和利用聚合物材料对机械载荷的化学反应的概念框架提升到一个新的实用水平。聚合物材料在技术上的巨大重要性主要是由于其机械性能的显著范围，即它们对机械负荷的响应。在宏观尺度上，这样的载荷（应力）改变了物体的体积形状，但材料的响应在长度和时间上扩展了许多数量级。几乎在聚合物的性质被认识到之后，对聚合物固体、熔体或溶液的某些简单操作就被证明可以导致聚合物骨干的断裂，而无需高温，而高温通常需要强共价键以可检测的速率断裂。这种效应通常被称为机械化学。机械化学被认为在控制(1)裂纹扩展和灾难性材料失效，(2)表面锚定聚合物在微流体诊断和高性能色谱中的稳定性，以及(3)脱盐膜、抗冲击材料（如防弹背心）和轮胎的行为方面很重要；并且在影响各种技术过程中(4)喷射（例如，在有机电子产品的喷墨材料沉积期间），(5)聚合物熔体加工，(6)高性能润滑，(7)提高石油采收率（例如，聚合物驱油），(8)湍流阻力减少（例如，在管道，消防，灌溉中）。利用局部反应性和机械负荷之间的耦合，既可以推进这些技术，也可以产生全新的材料和工艺，包括聚合物光致动（即直接将光转化为运动，为自主纳米机械设备提供动力，控制光学计算中的信息流，定位反射镜或太阳能捕获方案中的光伏电池），有效捕获废弃机械能，能够自主报告内应力和自我修复的材料以及在亚纳米尺度上研究聚合物动力学的工具。为了充分实现这一非凡的潜力，材料科学界需要一套理论、计算、合成和物理化学工具和模型来指导我们的工作，以确定单体和聚合物结构的化学成分和分子结构，从而产生具有所需应力响应特性的大块材料，并使聚合物动力学的分子研究成为可能，特别是在5-100纳米的长度尺度上（所谓的“可怕的差距”）。实现这一目标需要对定义机械载荷的宏观参数（例如，应力或应变张量）与控制化学反应性变化的分子特性（例如，活化能）之间的关系有一个一般的、定量的理解。EPSRC的资金将使我们能够通过一个集成（宏观）分子设计和合成、物理测量（使用各种现代光谱技术，包括单分子力谱和高分辨率x射线光电子能谱）、仪器设计、量子化学计算、统计力学和有限元建模和理论的项目来发展这样的理解。为了实现这一总体目标，我们将使用一系列专门设计的反应性单体，用于有效和准确的局部反应性动力学测量，并在整个物理系统范围内对结果进行分子解释，其行为受拉伸大分子动力学控制。这些系统的范围从单个孤立的拉伸聚合物链一直到负载下的大块非晶聚合物。

项目成果

Photomechanical Actuation of Ligand Geometry in Enantioselective Catalysis

对映选择性催化中配体几何形状的光机械驱动

• DOI: 10.1002/ange.201407494
• 发表时间: 2014
• 期刊: Angewandte Chemie
• 作者: Kean Z

Experimental Polymer Mechanochemistry and its Interpretational Frameworks

实验聚合物力化学及其解释框架

• DOI: 10.1002/cphc.201700521
• 发表时间: 2017
• 期刊: ChemPhysChem
• 影响因子: 2.9
• 作者: Akbulatov S

Selective ortho-C-H Activation in Arenes without Functional Groups.

• DOI: 10.1021/jacs.2c04621
• 发表时间: 2022-07-06
• 期刊: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
• 影响因子: 15
• 作者: Chan, Antony P. Y.;Jakoobi, Martin;Wang, Chenxu;O'Neill, Robert T.;Aydin, Gulsevim S. S.;Halcovitch, Nathan;Boulatov, Roman;Sergeev, Alexey G.
• 通讯作者: Sergeev, Alexey G.

Coumarin Dimer Is an Effective Photomechanochemical AND Gate for Small-Molecule Release.

香豆素二聚体是用于小分子释放的有效光学力学化学和门。

• DOI: 10.1021/jacs.3c07883
• 发表时间: 2023-10-25
• 期刊: JOURNAL OF THE AMERICAN CHEMICAL SOCIETY
• 影响因子: 15
• 作者: He, Xiaojun;Tian, Yancong;O'Neill, Robert;Xu, Yuanze;Lin, Yangju;Weng, Wengui;Boulatov, Roman
• 通讯作者: Boulatov, Roman