Kinetic rates of thermal transformations and diffusion in polymer systems measured during sub-millisecond laser-induced heating.
Kinetic rates of thermal transformations and diffusion in polymer systems measured during sub-millisecond laser-induced heating.
复制标题
在亚毫秒激光诱导加热过程中测量聚合物系统中热转变和扩散的动力学速率。
作者：
B. Jung;Jingquan Sha;F. Paredes;M. Chandhok;T. Younkin;U. Wiesner;C. Ober;M. Thompson
探测近固态（小分子和聚合物）的化学反应动力学是极具挑战性的，因为反应物的迁移率有限，缺乏合适的分析探针，最关键的是材料的温度稳定性有限。通过将温度暴露限制在极短的时间框架内（亚毫秒），可以获得超过800°C的温度，将动力学速率测量延长了许多数量级。在这里，我们展示了在模型系统上的测量，利用薄膜，激光加热和化学放大电阻的优点作为化学动力学速率的精细探针。化学反应和酸扩散速率的测量超过了10个数量级，揭示了与不同温度下关键机制变化相关的意想不到的大变化。这种研究近固态材料动力学的新方法有望大大提高我们对广泛的温度敏感、低迁移率材料中活性过程的理解。
Probing chemical reaction kinetics in the near-solid state (small molecules and polymers) is extremely challenging because of the restricted mobility of reactant species, the absence of suitable analytical probes, and most critically the limited temperature stability of the materials. By limiting temperature exposure to extremely short time frames (sub-millisecond), temperatures in excess of 800 °C can be accessed extending kinetic rate measurements many orders of magnitude. Here we demonstrate measurements on a model system, exploiting the advantages of thin-films, laser heating, and chemically amplified resists as an exquisite probe of chemical kinetic rates. Chemical reaction and acid diffusion rates were measured over 10 orders of magnitude, exposing unexpected and large changes in dynamics linked to critical mechanism shifts across temperature regimes. This new approach to the study of kinetics in near-solid state materials promises to substantially improve our understanding of processes active in a broad range of temperature-sensitive, low-mobility materials.