Realization of a two-dimensional glass, and the direct observation of its ordered-cluster structure and structural change

二维玻璃的实现及其有序簇结构和结构变化的直接观察

基本信息

批准号：
10440169
负责人：
OGUNI Masaharu
金额：
$ 8.58万
依托单位：
Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B).
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

Science of Supercooled liquids and glasses has not been developed enough because of the aspect that the arrangement of molecules is essentially disordered. The development of ordering in the molecular aggregation, however, plays an important role in their characteristic properties at low temperatures. We have proposed an "ordered-clusters aggregation model" for the structure of those systems. In this research, it was tried first to realize a two-dimensional glass and observe directly the molecular aggregation and its change, and second to discover or elucidate new phenomena based on the proposed model.1) A scanning tunneling microscope was constructed which works at liquid nitrogen temperature. o-Terphenyl molecules deposited on a graphite surface was identified, but it has not been succeeded yet to form and observe its mono-layer glass.2) α and β relaxation times of simple benzene-derivatives were investigated dielectrically with systematic change of the substituent groups at 1 and 3- … More positions. While the β relaxation times were rather independent of the size of substituents to within isopropyl group and the presence/absence of hydrogen-bond forming, -OH and NH_2, groups, α relaxation times depended strongly on those factors. The β relaxation strength was appreciably large in the sample cooled rapidly than slowly in the α glass transition region in advance.3) Homogeneous-nucleation-based crystallization was found in total in seven compounds with phenyl rings, indicating that the presence of the ring is important for its observation. It was also indicated to be important for the observation that the orientation of the crystal nucleus should coincide with that of the original crystal.4) Crystal nucleation was followed for o-benzylphenol after the liquid was cooled very rapidly from above fusion point to below the α glass transition temperature. It was found in a certain temperature region that the crystal nuclei were formed, then extinguished, and formed again after further long duration.5) In addition to a normal liquid (L_N) phase, another amorphous (L_C) phase was confirmed to exist in triphenylphosphite. Based on the α relaxation properties of the L_N and L_C phases, it was discussed that, in general, the α molecular rearrangement process is controlled by two relatively independent factors : the size of structurally ordered cluster and the degree of the order in the cluster, and that the relaxation time is basically determined by the latter factor. Less

超冷液体和眼镜的科学尚未足够开发，因为分子的排列本质上是无序的。然而，分子聚集中有序的发展在低温下其特征性能中起着重要作用。我们为这些系统的结构提出了一个“有序群集聚合模型”。在这项研究中，首先尝试实现二维玻璃并直接观察分子聚集及其变化，其次是基于提议的模型发现或阐明新现象的第二个。鉴定出沉积在石墨表面上的o-二苯基分子，但尚未成功地形成并观察其单层玻璃。2）α和β松弛时间简单的苯衍生物的β弛豫时间通过1和3--更多位置的次级基团的系统变化进行了轻轻研究。尽管β弛豫时间相当独立于异丙基群内的亚物质的大小，并且存在/不存在氢键形成，-OH和NH_2，α弛豫时间在很大程度上取决于这些因素。在样品中比在α玻璃过渡区域缓慢冷却的样品中β弛豫强度的良好。3）基于二核的结晶中，在七种具有苯基环的化合物中，总共发现了该环的存在，表明该环的存在对于其观察力很重要。这也表明对于观察到的观察至关重要，即晶体核的方向应与原始晶体的方向相吻合。4）在液体从融合点以上至低于α玻璃过渡温度以下的液体冷却后，晶核的晶核伴随着晶核。在某个温度区域中发现，形成了晶体核，然后延伸，然后在更长的持续时间后再次形成。5）除了正常液体（L_N）相外，还证实了另一种无定形（L_C）相在三苯基磷酸盐中存在。基于L_N和L_C相的α弛豫特性，讨论了，通常，α分子重排过程由两个相对独立的因子控制：结构有序的群集的大小和群集中的顺序程度，并且弛豫时间基本上由后期因素确定。较少的