Fast Dynamics in Polymers

在本程序中，我们通过实验研究了聚合物体系在很宽的温度范围内的动力学，从固态的深层到液态的深层。该程序的主要主题是分析不同聚合物中的快速动力学。这种动力学包括纳米尺度上的分子协同运动。这一运动是许多较慢过程的必要前驱，并强烈影响材料的宏观性质。方法主要有光散射法和中子散射法。这两种技术的结合给出了关于快速动力学光谱和分子水平上运动特性的详细信息。不同的理论方法，从模式耦合理论到非对称双势垒模型，都被用来测试和分析实验数据。讨论和发展了在较宽的温度和频率范围内一致地描述数据的新的模型近似。该计划是在聚合物动力学领域工作的不同小组(实验、理论和计算机模拟)之间广泛合作的起点。该程序的结果将使人们更好地理解聚合物体系中快速动力学及其特性的微观图景，并将导致固体和液体动力学的一致理论描述%分子运动是许多宏观材料性质的关键。这里的研究集中在分子频率(GHz-THz范围)和长度(纳米)尺度上的协同分子运动分析。这一研究结果将对聚合物动力学和无序材料及生物聚合物动力学的发展产生重大影响。在程序结果中获得的知识可用于设计具有所需性能的新塑料，特别是用于高频应用(光学通信、计算机、光学存储设备)。

In this program the dynamic of polymeric systems is studied experimentally in a broad temperature range, from deep in a solid state up to deep in a liquid state. The main subject of the program is analysis of the fast dynamics in different polymers. This dynamics includes cooperative molecular motion on a nanometer scale. This motion is a necessary precursor of many slower processes and strongly influences macroscopic properties of the material. The main methods are light and neutron scattering spectroscopy. The combination of these two techniques gives detailed information on the fast dynamics spectra and on peculiarities of the motion on a molecular level. Different theoretical approaches, from Mode-Coupling Theory to model of Asymmetric Double-Well Potentials, are tested and used for analysis of the experimental data. New model approximations that would consistently describe the data in a broad temperature and frequency ranges are discussed and developed. The program is a starting point for broad collaboration between different groups (experimental, theory and computer simulations) working in the field of polymer dynamics. The results of the program will bring better understanding of microscopic picture of the fast dynamics and its peculiarities in polymeric systems and will lead to development of consistent theoretical description of the dynamics in solid and liquid states%%%Molecular motion is a key for many macroscopic materials properties. The proposed here research is concentrated on analysis of cooperative molecular motion on a molecular frequency (GHz-THz range) and length (nanometer) scales. The results of the research will strongly influence the development of the field of polymer dynamics and dynamics of disordered materials and bio-polymers in general. The knowledge received I the result of the program can be useful for designing of new plastics with desired properties, especially for high-frequency applications (optical comunications, computers, optical memory storage devices).