To tailor properties of polymer composites are very important for their applications.Very small concentrations of nanoparticles can significantly alter their physical characteristics.In this work,molecular dynamics si...To tailor properties of polymer composites are very important for their applications.Very small concentrations of nanoparticles can significantly alter their physical characteristics.In this work,molecular dynamics simulations are performed to study the thermodynamic and structural properties of polystyrene/C60(PS/C60)composites.The calculated densities,glass transition temperatures,and coefficient of thermal expansion of the bulk PS are in agreement with the experimental data available,implying that our calculations are reasonable.We find that the glass transition temperature Tg increases accordingly with an added concentration of C60 for PS/C60 composites.However,the self-diffusion coefficient D decreases with increase of addition of C60.For the volumetric coefficients of thermal expansion(CTE)of bulk PS and PS/C60 composites,it can be seen that the CTE increases with increasing content of C60 above Tg(rubbery region).However,the CTE decreases with increasing content of C60 below Tg(glassy region).展开更多
This paper reports that the n-type organic thin-fihn transistors have been fabricated by using C60 as the active layer and polystyrene as the dielectric. The properties of insulator and the growth characteristic of C6...This paper reports that the n-type organic thin-fihn transistors have been fabricated by using C60 as the active layer and polystyrene as the dielectric. The properties of insulator and the growth characteristic of C60 film were carefully investigated. By choosing different source/drain electrodes, a device with good performance can be obtained. The highest electron field effect mobility about 1.15 cm2/（V. s） could reach when Barium was introduced as electrodes. Moreover, the C60 transistor shows a negligible ＇hysteresis effect＇ contributed to the hydroxyl-free of insulator. The result suggests that polymer dielectrics are promising in applications among n-type organic transistors.展开更多
The opticai properties of C,, chemicaiiy modified poiystyrene(C,, -PS copolymer) and the parent polystyrene (PS) films have been investigated.Addition of bulky C,, moiety, a special functional group, to the polystyren...The opticai properties of C,, chemicaiiy modified poiystyrene(C,, -PS copolymer) and the parent polystyrene (PS) films have been investigated.Addition of bulky C,, moiety, a special functional group, to the polystyrene by anovel organometallic reaction modified considerably the optical property of theparent polystyrene. The lattice periodicity of pure PS film is subject to someperturbation or distortion in varying degrees due to the covalent attachInent of bulkyC,, moiety to the polymer backbone. C,,-PS copolymer possesses a new energy ba-ndstructure with indirect forbidden band when compared with the parent PS.展开更多
The physical aging behavior of atactic polystyrene (aPS) films achieved under different drawing conditions has been studied by optical birefringence and modulate differential scanning: calorimeter (m.d.s.c.). The resu...The physical aging behavior of atactic polystyrene (aPS) films achieved under different drawing conditions has been studied by optical birefringence and modulate differential scanning: calorimeter (m.d.s.c.). The results show that on annealing at specific temperature below glass transition temperatue (T-g), the enthalpy relaxation (Delta H) and T-g decrease with increasing of birefringence (Delta n). On the other baud, the effect of molecular draw ratio (MDR) is confusing: Delta H and T-g decrease with increasing of MDR in the early stage of aging, but the MDR's effect become unobvious with the development of aging. It may be concluded that the ordered domain generated by the drawing below or above glass transition temperature will affect the development of physical aging behavior. The viewpoint of cohesional entanglement is used to account for the above observations.展开更多
The ability of water soluble β alanine C 60 adducts for superoxide anion radical scavenging has been studied by spectrophotometry and the modified pyrogallol auto oxidation method. It is found that β alanine C 60 ad...The ability of water soluble β alanine C 60 adducts for superoxide anion radical scavenging has been studied by spectrophotometry and the modified pyrogallol auto oxidation method. It is found that β alanine C 60 adducts have an excellent efficiency in eliminating superoxide radical generated from auto oxidation of pyrogallol. At a mass concentration level of 150 μg/mL for β alanine C 60 adducts, the radical scavenging efficiency is approximately equivalent to one enzyme unit, in vitro experiments show that β alanine C 60 adducts can enhance the activity of mouse thymus cells and prolong their life time span. It reveals the potential use of these β alanine C 60 adducts as the novel potent free radical scavengers in biological systems.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.11704329)the Scientific Research Fund of Sichuan Provincial Education Department of China(Grant No.15ZB293)+1 种基金the Pre-Research Project of Yibin University of China(Grant No.2019YY06)the Open Research Fund of Computational Physics Key Laboratory of Sichuan Province at Yibin University of China(Grant No.JSWL2014KF02).
文摘To tailor properties of polymer composites are very important for their applications.Very small concentrations of nanoparticles can significantly alter their physical characteristics.In this work,molecular dynamics simulations are performed to study the thermodynamic and structural properties of polystyrene/C60(PS/C60)composites.The calculated densities,glass transition temperatures,and coefficient of thermal expansion of the bulk PS are in agreement with the experimental data available,implying that our calculations are reasonable.We find that the glass transition temperature Tg increases accordingly with an added concentration of C60 for PS/C60 composites.However,the self-diffusion coefficient D decreases with increase of addition of C60.For the volumetric coefficients of thermal expansion(CTE)of bulk PS and PS/C60 composites,it can be seen that the CTE increases with increasing content of C60 above Tg(rubbery region).However,the CTE decreases with increasing content of C60 below Tg(glassy region).
基金supported by the National Natural Science Foundation of China (Grant No. 60676033)
文摘This paper reports that the n-type organic thin-fihn transistors have been fabricated by using C60 as the active layer and polystyrene as the dielectric. The properties of insulator and the growth characteristic of C60 film were carefully investigated. By choosing different source/drain electrodes, a device with good performance can be obtained. The highest electron field effect mobility about 1.15 cm2/（V. s） could reach when Barium was introduced as electrodes. Moreover, the C60 transistor shows a negligible ＇hysteresis effect＇ contributed to the hydroxyl-free of insulator. The result suggests that polymer dielectrics are promising in applications among n-type organic transistors.
文摘The opticai properties of C,, chemicaiiy modified poiystyrene(C,, -PS copolymer) and the parent polystyrene (PS) films have been investigated.Addition of bulky C,, moiety, a special functional group, to the polystyrene by anovel organometallic reaction modified considerably the optical property of theparent polystyrene. The lattice periodicity of pure PS film is subject to someperturbation or distortion in varying degrees due to the covalent attachInent of bulkyC,, moiety to the polymer backbone. C,,-PS copolymer possesses a new energy ba-ndstructure with indirect forbidden band when compared with the parent PS.
基金This work was Supported by the National Basic Research Project-Macromolecular Condensed State
文摘The physical aging behavior of atactic polystyrene (aPS) films achieved under different drawing conditions has been studied by optical birefringence and modulate differential scanning: calorimeter (m.d.s.c.). The results show that on annealing at specific temperature below glass transition temperatue (T-g), the enthalpy relaxation (Delta H) and T-g decrease with increasing of birefringence (Delta n). On the other baud, the effect of molecular draw ratio (MDR) is confusing: Delta H and T-g decrease with increasing of MDR in the early stage of aging, but the MDR's effect become unobvious with the development of aging. It may be concluded that the ordered domain generated by the drawing below or above glass transition temperature will affect the development of physical aging behavior. The viewpoint of cohesional entanglement is used to account for the above observations.
文摘The ability of water soluble β alanine C 60 adducts for superoxide anion radical scavenging has been studied by spectrophotometry and the modified pyrogallol auto oxidation method. It is found that β alanine C 60 adducts have an excellent efficiency in eliminating superoxide radical generated from auto oxidation of pyrogallol. At a mass concentration level of 150 μg/mL for β alanine C 60 adducts, the radical scavenging efficiency is approximately equivalent to one enzyme unit, in vitro experiments show that β alanine C 60 adducts can enhance the activity of mouse thymus cells and prolong their life time span. It reveals the potential use of these β alanine C 60 adducts as the novel potent free radical scavengers in biological systems.
