混合异构体的不寻常转换 十化化素 稳定玻璃
B J Kasting1, J P Gabriel2, M E Tracy1
1Department of Chemistry, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA.
The journal of physical chemistry. B
|June 23, 2023
概括
蒸汽沉积的甲基化 (DHIQ) 混合物形成高度稳定的玻璃,无论其异构成分如何. 这些稳定玻璃在化过程中表现出独特的转变行为,与其他已知的稳定玻璃系统不同.
科学领域:
- 材料科学 材料科学 材料科学
- 物理化学 物理化学
- 聚合物科学 聚合物科学
背景情况:
- 蒸汽沉积的混合物在技术上是创造先进材料的关键.
- 异构成分对眼镜动力稳定性的影响是一个尚未探索的领域.
- 了解玻璃稳定性对于需要长期材料完整性的应用至关重要.
研究的目的:
- 描述蒸汽沉积的 cis-和 trans-decahydroisoquinoline (DHIQ) 混合物的形成玻璃的能力.
- 为了研究异构成分对DHIQ眼镜运动稳定的影响.
- 探索稳定的DHIQ玻璃在异热回火过程中的转换机制.
主要方法:
- 电介放松光谱被用来探测DHIQ眼镜的动态.
- 用蒸汽沉积来制备混合异构体和纯的跨-DHIQ膜.
- 为了观察结构转变,进行了同热回火实验.
主要成果:
- 混合异构体和纯的跨-DHIQ均形成具有高动力稳定的玻璃,在约10^4个结构松时间内转化.
- 异构成分并没有显著影响到所获得的最大动力稳定性.
- 二次放松,归因于分子内形状变化,在高度稳定的眼镜中被抑制.
- 转型通过增长前线机制启动,过渡到同质的散装机制.
- 大量转化的时间依赖性偏离了典型的核和生长模型.
结论:
- 蒸汽沉积的DHIQ混合物可以形成非常稳定的玻璃,稳定性基本上独立于异构比率.
- 高度稳定的DHIQ眼镜表现出抑制的二次放松.
- 这些稳定眼镜的转换动力学呈现了一种新的行为,不能用标准模型来解释,这表明了独特的放松途径.
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