Molecular aggregation state-photopolymerization behavior relationship of lithium 10,12-heptacosadiynoate monolayer
Molecular aggregation state-photopolymerization behavior relationship of lithium 10,12-heptacosadiynoate monolayer
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单层10,12-二十七二炔酸锂的分子聚集态-光聚合行为关系
DOI：
10.1021/la00009a041
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发表时间：
1995
期刊：
影响因子：
3.9
通讯作者：
T. Kajiyama
中科院分区：
文献类型：
--
作者：
K. Kuriyama;H. Kikuchi;Y. Oishi;T. Kajiyama
本文首次系统地研究了温度对10，12-十七碳二炔酸锂单分子膜聚合的影响及其与聚集态结构的关系。根据单分子膜弹性模量与亚相温度的关系和单分子膜的电子衍射（艾德）图，研究了单分子膜在水表面的聚集状态。水表面上的单分子层被分为熔融单分子层，结晶的和玻璃态的，取决于Tsp在与水表面上的单分子层的熔融温度（Tm）的比较。通过紫外-可见吸收光谱的紫外光照射时间依赖性研究了不同聚集态的单分子膜的光聚合行为。在熔融状态下的单层的情况下，光聚合反应性较低。另一方面，聚（丁二炔）（PDA）的蓝色形式的单分子层，其具有在640 nm处的吸收峰，形成后光照射到结晶单分子层。此外，在玻璃态单分子膜的情况下，发现通过紫外光照射形成了在540 nm处具有吸收峰的PDA红色单分子膜。PDA红色形式的π电子的离域长度将短于PDA蓝色形式的离域长度，如对应于π-π * 跃迁的主吸收峰的波长所表明的。PDA蓝型和PDA红型之间的π电子离域长度的差异可以通过聚合反应期间引起的共轭PDA主链上的晶格应变来解释。
This report is the first systematic study of the temperature effect on polymerization of lithium 10,12-heptacosadiynoate monolayer with relation to its aggregation structure. A molecular aggregation state of the monolayer on the water surface was investigated on the basis of the subphase temperature (T sp ) dependences ofthe elastic modulus and the electron diffraction (ED) pattern ofthe monolayer. The monolayer on the water surface was classified into a molten monolayer, a crystalline one and a glassy one, depending on T sp in comparison with the melting temperature (T m ) of the monolayer on the water surface. The photopolymerization behaviors of the monolayers in various aggregation states were also investigated by the ultraviolet (UV) light irradiation time dependences of UV-visible absorption spectrum. The photopolymerization was less reactive in the case of the monolayer in a molten state. On the other hand, the poly(diacetylene) (PDA) blue form monolayer, which had the absorption peak at 640 nm, was formed upon photoirradiation to the crystalline monolayer. Moreover, in the case of the glassy monolayer, PDA red form monolayer, which had the absorption peak at 540 nm, was found to be formed by UV light irradiation. The delocalization length of a π-electron in the PDA red form would be shorter than that in the PDA blue form, as suggested by the wavelength of the main absorption peak corresponding to π-π * transition. The difference in the delocalization length of π-electron between the PDA blue form and the PDA red form could be explained by the lattice strain on conjugated PDA main chains caused during the polymerization reaction.