气溶尺寸对玻璃过渡温度的影响
Sunandan Mahant1,2, Jefferson R Snider3, Sarah S Petters1,2
1Department of Chemical and Environmental Engineering, University of California Riverside, Riverside, California 92521, United States.
The journal of physical chemistry letters
|July 17, 2024
概括
粒子大小显著影响无形纳米粒子的玻璃到液体过渡温度. 这项研究揭示了对糖颗粒这种相位过渡的关系的尺寸依赖性转变.
科学领域:
- 物理化学 物理化学
- 材料科学 材料科学 材料科学
- 大气科学 大气科学
背景情况:
- 纳米颗粒的无形相状态会影响它们在大气中的寿命和环境影响.
- 相对湿度和化学成分是影响玻璃变液的已知因素.
- 粒子大小对这种相位过渡的影响仍然不太清楚.
研究的目的:
- 实验性地研究颗粒大小对悬浮的砂糖颗粒无形相变的影响.
- 为了确定颗粒大小如何影响玻璃过渡温度下降.
主要方法:
- 在悬浮的砂糖颗粒中对无形相变的实验探测.
- 在100-700nm和更小的范围内变化的颗粒大小.
- 分析粒子直径和玻璃过渡温度降低之间的关系.
主要成果:
- 观察到玻璃过渡温度 (ΔTg) 的尺寸依赖的低压.
- 对于100-700nm的粒子,ΔTg遵循预测的D-1比例.
- 对于较小的颗粒大小,比例转向 ΔTg D−1/2.2.
- 薄膜和纳米封闭化合物的文献数据显示,与预期的行为有相似的偏差.
结论:
- 粒子大小和玻璃过渡温度降低之间的关系在较小的尺寸上偏离了既定的理论.
- 这些偏差不是由基质效应引起的,这表明内在的尺寸依赖现象.
- 需要进一步的研究,以充分阐明观察到的大小依赖的比例.
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