Some new mesogen-jacketed liquid crystalline polymers (MJLCP) with polymer backbones, spacers, and mesogenic units of different structures were synthesized by radical polymerization. The mesomorphic behavior of these ...Some new mesogen-jacketed liquid crystalline polymers (MJLCP) with polymer backbones, spacers, and mesogenic units of different structures were synthesized by radical polymerization. The mesomorphic behavior of these polymers was examined using differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). Their liquid crystallinity is influenced by the variation of polymer backbone, spacer, mesogenic unit and its terminal groups. The results show that 1) a more flexible polymer main-chain is more favorable to the formation of a liquid crystal phase, while 2) a flexible spacer will decrease the 'Jacket Effect' and the liquid crystallinity and 3) a subtle modification of the terminal groups on the mesogenic unit may also have a significant influence on properties of the polymers.展开更多
Polymer backbone plays a fundamental role in determining the molecular architecture and properties of polymers.Polymers can be modified by incorporating heteroatoms into their backbones to achieve tunable optical and ...Polymer backbone plays a fundamental role in determining the molecular architecture and properties of polymers.Polymers can be modified by incorporating heteroatoms into their backbones to achieve tunable optical and mechanical properties,such as polyamide,polythioether and polysilane[1].The transition from nonconjugated to conjugated backbones of polymers challenges the traditional view of polymers as insulators,leading to the development of conductive polymers[2].In contrast,metal elements far surpass non-metal elements in both the variety of elemental types and the diversity of their outer-shell electrons,incorporating which into the polymer backbone is promising to create polymer materials with unique properties and applications,such as high mechanical strength and electrical conductivity[3].Integration of metal atoms into the polymer backbones has been reported.However,the lack of uniformity and continuity in the interaction of metal atoms limits electron transfer efficiency and hinders the full utilization of metal elements within polymer materials[4].To this end,a novel metal-backboned polymer was proposed[5,6],wherein the polymer backbone consists entirely of metal atoms interconnected through metal–metal bonds.This novel polymer was found with exceptional optical and electrical properties,showing promising applications in photoelectric devices,flexible electronics,and microwave absorption materials[7,8].展开更多
The optical properties of one mono-substituted polyacetylene and two di-substituted polyacetylenes have been investigated. Each of the substituted polyacetylenes bears a carbazole unit in the side chain. In spite of t...The optical properties of one mono-substituted polyacetylene and two di-substituted polyacetylenes have been investigated. Each of the substituted polyacetylenes bears a carbazole unit in the side chain. In spite of the differences in their molecular structures, the dilute solutions(about 1×10-6 M) of these substituted polyacetylenes exhibit the same absorptions and deep-blue emissions(about 360 nm). Interestingly, the absorption and emission spectra of these substituted polyacetylenes are similar to those of the small molecule carbazole. As the concentration of the substituted polyacetylenes increases to about 1×10-6 M, we have detected intense blue emissions at about 475 nm. Our results indicate that the absorption, the deep-blue emission(about 360 nm) and the intense blue emission(about 475 nm) originate from the carbazole chromophores in the side chain.展开更多
基金This Project was supported by China Postdoctoral Science Foundation and National Natural Science Foundation of China (No. 59873001).
文摘Some new mesogen-jacketed liquid crystalline polymers (MJLCP) with polymer backbones, spacers, and mesogenic units of different structures were synthesized by radical polymerization. The mesomorphic behavior of these polymers was examined using differential scanning calorimetry (DSC) and polarizing optical microscopy (POM). Their liquid crystallinity is influenced by the variation of polymer backbone, spacer, mesogenic unit and its terminal groups. The results show that 1) a more flexible polymer main-chain is more favorable to the formation of a liquid crystal phase, while 2) a flexible spacer will decrease the 'Jacket Effect' and the liquid crystallinity and 3) a subtle modification of the terminal groups on the mesogenic unit may also have a significant influence on properties of the polymers.
基金supported by the Ministry of Science and Technology of the People’s Republic of China(2022YFA1203001 and 2022YFA1203002)the National Natural Science Foundation of China(T2321003,22335003,and 22105045)Science and Technology Commission of Shanghai Municipality(21511104900 and 20JC1414902).
文摘Polymer backbone plays a fundamental role in determining the molecular architecture and properties of polymers.Polymers can be modified by incorporating heteroatoms into their backbones to achieve tunable optical and mechanical properties,such as polyamide,polythioether and polysilane[1].The transition from nonconjugated to conjugated backbones of polymers challenges the traditional view of polymers as insulators,leading to the development of conductive polymers[2].In contrast,metal elements far surpass non-metal elements in both the variety of elemental types and the diversity of their outer-shell electrons,incorporating which into the polymer backbone is promising to create polymer materials with unique properties and applications,such as high mechanical strength and electrical conductivity[3].Integration of metal atoms into the polymer backbones has been reported.However,the lack of uniformity and continuity in the interaction of metal atoms limits electron transfer efficiency and hinders the full utilization of metal elements within polymer materials[4].To this end,a novel metal-backboned polymer was proposed[5,6],wherein the polymer backbone consists entirely of metal atoms interconnected through metal–metal bonds.This novel polymer was found with exceptional optical and electrical properties,showing promising applications in photoelectric devices,flexible electronics,and microwave absorption materials[7,8].
基金The Project Sponsored by the Scientific Research Foundation for the Returned Overseas Chinese Scholars ,State Education Ministry ,2005Natural Science Foundation of Guangdong Province(5300568)+1 种基金Key Scienceand Technology Research Foundation of State Education Ministry (206110)National Natural ScienceFoundation of China(10674091)
文摘The optical properties of one mono-substituted polyacetylene and two di-substituted polyacetylenes have been investigated. Each of the substituted polyacetylenes bears a carbazole unit in the side chain. In spite of the differences in their molecular structures, the dilute solutions(about 1×10-6 M) of these substituted polyacetylenes exhibit the same absorptions and deep-blue emissions(about 360 nm). Interestingly, the absorption and emission spectra of these substituted polyacetylenes are similar to those of the small molecule carbazole. As the concentration of the substituted polyacetylenes increases to about 1×10-6 M, we have detected intense blue emissions at about 475 nm. Our results indicate that the absorption, the deep-blue emission(about 360 nm) and the intense blue emission(about 475 nm) originate from the carbazole chromophores in the side chain.
