厚度对非极性聚合物薄膜驻极体电荷储存及电荷动态特性的影响

以Du Pont公司的商用Teflon FEP A型薄膜为例，通过热脉冲技术、等温表面电位衰减测量和开路热刺激放电电流谱分析等实验结果，讨论了经常温和高温电晕充电后样品厚度对薄膜驻极体的沉积电荷密度、薄膜驻极体的内电场、体电导率以及电荷储存稳定性的影响.通过热脉冲技术组合电导率温度曲线的测量，研究了在不同温度条件下样品厚度对沉积电荷层的平均电荷重心移动的影响.结果表明：在充电参数一定的条件下，随着膜厚的降低，储存电荷密度上升，但电荷稳定性有所下降.因此，合理地调控薄膜厚度，可以有效地优化驻极体的电荷储存能 关键词： 厚度 驻极体 电荷储存能力 电荷稳定性     

Migration of protons in a chain of tyrosine residues

This article deals with the proton migration in a tyrosine stack, which models the proton channels existing in a number of proteins, including tubulin. The magnesium ion Mg²⁺ within the complex with guanosine triphosphate facilitates dissociation of a water molecule through initiating a shift of protons along the chain composed of relatively distant tyrosine residues. The process is thermodynamically stable (ΔG₂₉₈<0). The energy barrier for the protein shift does not exceed 3.15 kJ/mole. A relatively weak electrostatic field mimicking electret properties of proteins facilitates long‐distance proton migration. © 2001 John Wiley & Sons, Inc. Int J Quantum Chem 84: 409–415, 2001     

压力膨化处理对正极性聚丙烯蜂窝膜的驻极体性质的影响

压力膨化处理工艺能够显著改善聚丙烯蜂窝薄膜（cellular polypropylene） 驻极体的压 电活性.通过热脉冲技术、表面电位衰减测量及TSD 电流谱分析等研究了经恒压正电晕充电 的聚丙烯蜂窝膜的陷阱能级分布特征，讨论了压力膨化处理工艺对这类蜂窝膜驻极体电荷稳 定性及电荷输运特性的影响.结果说明，PP 蜂窝膜内存在着位于中能级区的能值各异的三种 分立陷阱，深能值陷阱和浅能值陷阱的大多数位于孔洞膜近表面的体层或体内，而中等能值 陷阱则主要位于自由面附近.压力膨化处理改变了PP 蜂窝膜的能阱状态并在一定程度上降低 了这类孔洞膜驻极体的电荷储存稳定性，但没有明显影响其由慢再俘获效应占主导地位的脱 阱电荷输运特性. 关键词： 压力膨化处理 聚丙烯蜂窝膜 驻极体 电荷储存与陷阱分布 电荷输运     

Estimation of electrostriction coefficients of a nonlinear optical polymer electret

The effect of organic chromophores incorporated into a polymer electret and responsible for its nonlinear optical (NLO) response to an applied electric field on the electrostriction coefficients (ESC) of the material is studied. Analytical expressions for the ESC were derived in the framework of a model proposed earlier, which includes the effect of a locally anisotropic, polarizable and deformable environment on the electric characteristics of the chromophore. The dependence of the ESC on both macroscopic and microscopic parameters of the molecular system is established. Numerical estimates of the ESC for poly(methyl methacrylate) doped with the dye Disperse Red 1 and dimethylaminonitrostilbene-doped polycarbonate agree with experimental data in order of magnitude. The relations obtained can be used in the design of novel organic NLO materials. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 7, pp. 1324–1329, July, 2008.     

The aerosol penetration through an electret fibrous filter

The aim of this paper is to present a theoretical study of the aerosol penetration through an electret fibrous filter, using a numerical approach. The aerosol sizes considered in this study were in the submicron range, and in the numerical model, the conventional mechanical mechanisms (impaction, interception, diffusion and gravitationally settling) were taken into consideration along with the electrostatic mechanisms, including the Coulombic and dielectrophoretic effects. The aerosol penetration through an electret fibrous filter is heavily dependent on the aerosol penetration of a single fibre. The aerosol penetration through a single electret fibre under various filtration conditions was calculated. The effects of aerosol diameter, aerosol and fibre charge state, face velocity, packing density and aerosol dielectric constant on the aerosol penetration were investigated.     

恒流电晕充电对聚四氟乙烯多孔薄膜驻极体驻极态的影响

利用常温下恒流和恒压电晕充电、充电后的等温表面电位衰减、热刺激放电和扫描电镜等实 验手段研究了恒流和恒压电晕充电技术对聚四氟乙烯多孔薄膜驻极体驻极态的影响.与恒压电晕充电相比较，恒流电晕充电时由于流过薄膜的电流恒定，增加了注入电荷在多孔结构厚度方向界面处的俘获概率，使沉积电荷密度上升，改善了驻极体的储电能力.然而，这些位于不同层深多孔界面处的俘获电荷在这类功能膜储存或使用过程中，经外激发从脱阱位置 以跳动（hopping）模式输运至背电极的路径相对缩短将导致脱阱电荷衰减较快. 关键词： 恒流电晕充电 聚四氟乙烯多孔膜 驻极体 电荷稳定性     

Influence of physical aging on the performance of corona‐charged amorphous polymer electrets

The influence of physical aging on the electret properties before corona charging of three amorphous polymers, polyetherimide (PEI), poly(phenylene ether) (PPE), and polystyrene (PS), as well as with blends of PPE and PS, was investigated. The degree of aging was monitored by determining the enthalpy relaxation Δh using differential scanning calorimetry (DSC). The electret performance was evaluated by isothermal potential decay (ITPD) at elevated temperatures and by thermal stimulated discharge (TSD) measurements. It was demonstrated that physical aging below the glass transition temperature substantially improves the electret performance of amorphous polymers by reducing the free volume and thus hindering charge motion. As an example, the performance of nonaged PEI was improved by physical aging at 200 °C for 4 days from 18 to 95% retained charge after 24 h at 120 °C. A similar beneficial influence of physical aging on the charge storage capability was achieved using blends of PPE with PS. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 990–997, 2010     

压力膨化后的热处理温度对PP蜂窝膜驻极体机电性质的影响

研究了经压力膨化后的热处理温度对聚丙烯蜂窝膜(cellular PP)驻极体机电性能的影响.结果表明，在从常温至PP熔融温区内，压力膨化工艺处理后PP蜂窝膜的厚度随着热处理温度的升高而逐渐增大；然而热处理温度对PP蜂窝膜的压电活性及其相关性质的影响具有显著不同的规律，在90℃时，PP蜂窝膜的弹性模量和机电耦合系数分别出现谷值和峰值，同时压电d₃₃系数达到377pC/N的最大值.随着热处理温度的升高，它们的谐振频率的变化范围约为794到371kHz. 关键词： 热处理温度 PP蜂窝膜 压电性 压力膨化工艺     

Peculiarities of the Electret State of Melt-Spun and Melt-Blown Fibrous Polypropylene Materials

The charge state of melt-spun and melt-blown polypropylene fibers is investigated. It is shown that the production of fibers by melt-spinning and melt-blowing technologies promotes the formation of a spontaneous polarization charge. Possible mechanisms of fiber polarization are analyzed. The influence of parameters of the melt-spinning technological process and forced electrization of fibers during their formation in stationary and alternating electric fields on the magnitude and stability of the electret charge is examined. It is established that the application of a corona discharge to fiber polarization is more efficient for the electret state formation.