为了进一步研究聚合物基复合材料的拉伸效应, 采用简单的物理混合法制备了Ni/PVDF复合薄膜并在120℃下进行拉伸改性研究. 结果表明: 镍含量远低于渗流阈值的样品, 通过拉伸实现了与渗流效应类似的介电常数剧增的拉伸渗流效应;在伸长倍数为2. 3时介电常数急剧增大, 最大增幅17倍(12→220), 同时电导率也增大了4～5个数量级, 薄膜有绝缘体向导体转变的趋势. 介电常数随拉伸倍数增加而大幅增加, 是因为复合薄膜中的镍颗粒在外力拉伸作用下, 其分布、微观结构逐步发生变化, 以致形成了杆状镍颗粒群和微平行电容器结构等导电网络, 发生拉伸渗流效应;同时, 电导率的大幅增加也符合渗流理论的特征.
In order to further understand the stretching effect of polymer-based composites, the Ni/PVDF films were prepared using a simple physics blending and then stretched at 120℃ to improve the electronic properties. The results show that there is an abrupt increase of 17 times(12→220)in the dielectric constant of the stretched samples at the stretching ratio of 2. 3 with Ni content less than the percolation threshold, which is similar to percolation and named stretching-induced percolation. Additionally, an insulation-conduction transition tends to occur with enhancement of 4～5 orders of magnitude in conductivity after stretching. The enhancement in the dielectric constant with increase of stretching ratio is attributed to the gradual formation of conductive networks induced by stretching, which consists of a great many nickel groups and micro-parallel-capacitors. The large increase in conductivity is in agreement with the percolation theory before and after stretching.
参考文献
| [1] | Meng X J,Kliem H,Lin T,Chu J H.Electric field induced conversion in the nature of the phase transition from the first order to the second order for Langmuir Boldgett polymer films[J].Applied Physics Letters,2007,91:102903-102905. |
| [2] | Xu Haisheng,Cheng g Y,Olson D,Mai T,Zhang Q M,Kavarnos G.Ferroelectric and electromechanical properties of poly(vinylidene-fluoride-trifluoroethylene-chlorotrifluo-roethylene)terpolymer[J].Applied Physics Letters,2001,78:2360-2362. |
| [3] | Jungpark Y,Jukang S,Park C,Woo E,Skin K,Jinkim K.Recovery of remanent polarization of poly(vinylidene fluoride-co-trifluoroethylene)thin film after high temperature annealing sign topographically nanpstructured aluminuum bottom electrode[J].Applied Physics Letters,2007,90:222903-222905. |
| [4] | 党智敏,王海燕,王岚.新型高温高介电无机/有机功能复合材料[J].复合材料学报,2005,22(5):9-15.Dang Zhimin,Wang Haiyan,Wang Lan.New inorganic/organic functional composites with high temperature and high dielectric constant[J].Aeta Materiae Compositae Sinica,2005,22(5):9-15. |
| [5] | Lim S H,Rastogi A C,Desu S B.Electrical properties of metal-ferroelectric insulator-semiconductor structures based on ferroelectric polyvinylidene fluoride copolymer film gate for nonvolatile tandom access memory application[J].Journal of Applied Physics,2004,96:5673-5682. |
| [6] | Qiu P F,Zhang S Y,Shui X J.Photoacoustic study of thermal properties of biological tissues detected by PVDF film transducer[J].The Europe Physics Journal Special Topics,2008,153:487-490. |
| [7] | Bai Y,Cheng Z Y,Bharti V,Xu H S,Zhang Q M.High-dielectric-constant ceramic-power polymer composites[J].Applied Physics Letters,2000,76:3804-3806. |
| [8] | Dang Z M,Nan C W,Xie D,Zhang Y H,Tjong S C.Dielectric behavior and dependence of percolation threshold on the conductivity of fliers in polymer-semiconductor composites[J].Applied Physics Letters,2004,85:97-99. |
| [9] | Hsing H I,Lin K,Yen F,Hwang C.Effects of particle size of BaTiO_3 powder on the dielectric properties of BaTiO_3/PVDF composites[J].Journal of Material Science,2001,36:3809-3815. |
| [10] | Li Y J,Xu M,Feng J Q,Dang Z M.Dielectric behavior of a metal-polymer composite with low percolation threshold[J].Applied Physics Letters,2006,89:072902-072904. |
| [11] | Nan C W.Physics of inhomogeneous inorganic materials[J].Progress Materials Science,1993,37(1):1-116. |
| [12] | Dang Z M,Lin Y H,Nan C W.Novel ferroelectric polymer composites with high dielectric constants[J].Advanced Materials,2003,15:1625-1628. |
| [13] | Dang Z M,Shen Y,Nan C W.Dielectric behavior of three-phase percolation Ni-BaTiO_3/polyvinylidene fluoridecomposites[J].Applied Physics Letters,2002,81:4814-4816. |
| [14] | Panda M.Srinivas V,Thakur A K.On the question of percolation threshold in polyvinylidene fluoride/nanocrystalline nickel composites[J].Applied Physics Letters,2008,92:132905-132907. |
| [15] | Panda M,Srinivas V,Thakur A K.Surface and interfacial effect of filler particle on electrical properties of polyvinyledene fluoride/nickel composites[J].Applied Physics Letters,2008,93:242908-242910. |
| [16] | Wang Y,Ren K L,Zhang Q M.Direct piezoelectric response of piezopolymer polyvinylidene fluoride under high mechanicalstrain and stress[J].Applied Physics Letters,2007,91:222905-222907. |
| [17] | Sajkiewicz P,Wasiak C,Goclowski Z.Phase transitions during stretching of poly (vinylidene fluoride)[J].European Polymer Journal,1999.35:423-429. |
| [18] | Correia H M G,Ramos M M D.Modeling molecular transformations in ferroelectric polymers induced by mechanical and electrical means[J].Ferroelectrics,2006,388:179-184. |
| [19] | Bharti V,Xu H S,Shanthi G,Zhang Q M,Liang K M.Polarization and structural properties of high-energy electron irradiated poly (viylidene fluoride-trifluoroethylene)copolymer films[J].Journal of Applied Physics,2000,87:452-461. |
| [20] | Hu X J,Yao K,Gan B.Phase transition and properties of a ferroelectric poly(vinylidene fluoride-hexaflouropropylene)copolymer[J].Journal Applied Physics,2005,97:084101-084106. |
| [21] | Dang Z M,Yao S H,Xu H P.Effect of tensile strain on morphology and dielectric property in nanotube/polymer nanocomposites[J].Applied Physics Letters,2007,90:012907-012909. |
| [22] | Yao S H,Dang g M,Xu H P,Jiang M J,Bai J B.Exploration of dielectric constant dependence on evolution of microstructure in nanatube/ferroelectrie polymer nanocomposites[J].Applied Physics Letters,2008,92:082902-082904. |
| [23] | 仝金雨,姜胜林,刘栋,金学淼.退火温度PVDF薄膜结构的影响及其性能研究[J].功能材料,2006,37(10):1569-1571.Tong Jinyu,Jiang Shenglin.Liu Dong,Jin Xuemiao.Study oninfluence of anneal temperature on PVDF films and theirperformance[J].Journal of Functional Materials,2006,37(10):1569-1571. |
| [24] | Chang W Y,Fang T H.Lin S Y.Lin Y C.Phasetransformation and thermomechanical characteristics of stretched polyvinylidene fluoride[J].Material Science and Engineering A,2008,480:477-482. |
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