毫米级栅型电场分布FEP薄膜驻极体的制备及其电荷存储性能研究

采用电晕注极和热注极技术,在厚度为25μm的氟化乙丙烯共聚物(FEP)表面制备了宽度为2 mm和3mm的具有栅型电场分布的驻极体,研究了注极温度和电极宽度对其电荷存储性能的影响.样品注极后经150天的存储,栅型电场分布变得清晰而有规律,覆盖铝电极区电位已衰减至接近零,未覆盖铝电极区仍保持高电位;对电极宽度为2 mm和3 mm的样品,覆盖铝电极区与未覆盖铝电极区的表面电位差分别为110 V和130V(电场强度差分别为44 k V/cm和52 k V/cm).表面电位跟踪测试结果表明:电晕注极样品初始表面电位高于热注极样品;在相同的注极方法下,注极温度越高初始表面电位越高,电极宽度越小初始表面电位越低.依据电晕注极和热注极原理对实验结果的分析表明,FEP和金属铝在电荷存储性能上的差异是FEP表面蒸镀铝电极后能获得栅型电场分布的原因所在.

聚丙烯薄膜的表面结构与驻极体性能相关性研究

以聚丙烯颗粒为原料、表面纳米化石英玻璃为模板,通过热压法制得表面具有不同形貌的聚丙烯薄膜,再经电晕充电形成驻极体。采用原子力显微镜技术分析了薄膜的表面结构,并用表面电位跟踪和热刺激放电技术测试了不同表面结构聚丙烯薄膜的电荷存储性能。表面电位测试结果表明,其电荷存储性能与薄膜表面的微观结构密切相关,薄膜表面越粗糙,捕获电子的能力越强,但其电荷存储稳定性差异不大。热刺激放电技术测试结果表明,其陷阱能级与表面粗糙度无关。

熔喷非织造布的驻极技术研究进展

为深入了解熔喷非织造布的驻极技术研究现状,系统综述了熔喷非织造布的驻极技术、熔喷非织造布的电荷存储性能及驻极熔喷非织造布的发展前景;归纳了电晕充电、摩擦起电、静电纺丝和水驻极等6种驻极技术的特点与驻极机制,重点剖析了电晕驻极和水驻极处理技术和应用现状;介绍了静电存储及其稳定性的机制,进一步分析了驻极体材料、驻极工艺、聚合物晶体结构对熔喷非织造布静电存储性能的影响。此外,针对目前驻极技术在应用领域面临的挑战指出,开发多功能、高附加值的新型驻极材料和多重驻极技术结合是驻极熔喷非织造布未来的主要发展方向。

Electron configurations at 3d orbital of metal ion determining charge transition process in memory devices

Functional polymeric materials with electrical bi-stable states possess significant potential for high-density data storage due to their nanoscale memory site,threedimensional-stacking ability and intrinsic flexibility.Aromatic polyimides bearing donor-acceptor(D-A)skeleton could form the charge transfer complex(CTC)under an electrical field,leading to their feasibility as memory materials.Three novel porphyrinated polyimides DATPP-DSDA,Zn-DATPP-DSDA and Mn-DATPP-DSDA were designed and synthesized for information memory applications.Metal ions with different electron configurations at 3 d orbital have a determining influence on memory behaviors of polyimides:nonvolatile write-once-read-many-times memory(WORM)for DATPP-DSDA,volatile static random access memory(SRAM)for Zn-DATPP-DSDA,but no memory performance for Mn-DATPP-DSDA.By comparing the contribution of orbital transition and hole-electron distribution of chargetransfer excited states,roles of metal ions in regulating memory types were discussed.Molecular simulation results indicate that the Zn ion could play a bridge role in paving the route for excited electrons from a D to an A,while a trap role for the Mn ion in hindering this process.This study proves the feasibility of the strategy for modulating the memory behaviors of porphyrinated polyimides by varying the central metal ion and provides the exact effects of various metal ions on regulating charge transfer processes.

Bimetallic oxide coupled with B-doped graphene as highly efficient electrocatalyst for oxygen evolution reaction

Developing electrocatalysts with high performance and low cost for the oxygen evolution reaction(OER)is of great importance for fabricating renewable energy storage and conversion devices.Here,a series of boron-doped graphene(BG)-supported bimetallic oxides of Co and Ni were obtained and served as OER electrocatalysts.Surprisingly,the annealed Co-Ni-Ox/BG with a Co/Ni ratio of 1:1 exhibits high performance toward oxygen evolution in alkaline electrolyte.The overpotential is only 310 mV at the current density of 10 mA cm-2,superior to many mono-metallic oxides reported before,and even comparable to the commercial RuO2.The regulation of charge distribution in bimetallic oxides and the strong synergistic coupling effects together contribute to the superior electrocatalytic performance of the Co-Ni-Ox/BG toward OER.This study also offers several effective ways to design high-performance OER electrocatalysts for water splitting.

The effect of electric charge on the mechanical properties of graphene

The effect of electric charge on the mechanical properties of graphene under tensile loading is investigated by using molecular dynamics method.A modified atomistic moment method based on the classical electrostatics theory is proposed to obtain the distribution of extra charges induced by an external electric field and net electric charges stored in graphene.The electrostatic interactions between charged atoms are calculated using the coulomb law.The results show that the Young's modulus and the critical fracture stress under uniaxial tension decrease with the increase of electric potential and net charges on graphene.The failure of graphene induced by electric charges is found to be controlled by charge level.The results indicate that the carbon-carbon bonds at the edge of graphene will break first.