1微米长度尺度控制低能玻璃的动力学稳定性
One micron length scale controls kinetic stability of low energy glasses
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中文总结 AI 辅助
该研究通过交流纳米量热法发现，低能吲哚美辛玻璃的转变时间随薄膜厚度变化，1微米为转变机制的分界尺度，揭示了控制其动力学稳定性的关键长度尺度。
中文摘要 AI 辅助
采用交流纳米量热法测量低能吲哚美辛玻璃等温转变为过冷液体时的可逆热容Cp。当薄膜厚度从75 nm增加到600 nm时，转变时间增加了一个数量级以上，与表面引发的转变机制一致。最终，厚度在1.4至30微米之间的薄膜转变时间保持恒定，表明存在独特的本体转变路径。接近1微米的玻璃样品呈现尺寸依赖的转变动力学，这一观察结果前所未见。我们将厚度依赖关系在1微米处的交叉，解释为本体低能玻璃中转变引发位点间的平均距离。
英文摘要
AC nanocalorimetry was used to measure the reversing heat capacity Cp of low energy indomethacin glasses as they isothermally transform into the supercooled liquid. As the film thickness increases from 75 to 600 nm, the transformation time increases by more than an order of magnitude, consistent with a surface-initiated transformation mechanism. Eventually, the transformation time becomes constant for films between 1.4 and 30 microns indicating a distinct bulk transformation pathway. The observation of size-dependent transformation kinetics for glass samples approaching 1 micron is unprecedented. We interpret the crossover in thickness dependence at 1 micron to signify the average distance between transformation initiation sites in the bulk low energy glass.
