Wei Junji, Zhang Zhongbo, Tseng Jung-Kai, Treufeld Imre, Liu Xiaobo, Litt Morton H, Zhu Lei
Institute of Microelectronics and Solid State Electronics, University of Electronic Science and Technology of China , Chengdu, Sichuan, P. R. China.
ACS Appl Mater Interfaces. 2015 Mar 11;7(9):5248-57. doi: 10.1021/am508488w. Epub 2015 Mar 2.
In this report, a dipolar glass polymer, poly(2-(methylsulfonyl)ethyl methacrylate) (PMSEMA), was synthesized by free radical polymerization of the corresponding methacrylate monomer. Due to the large dipole moment (4.25 D) and small size of the side-chain sulfone groups, PMSEMA exhibited a strong γ transition at a temperature as low as -110 °C at 1 Hz, about 220 °C below its glass transition temperature around 109 °C. Because of this strong γ dipole relaxation, the glassy PMSEMA sample exhibited a high dielectric constant of 11.4 and a low dissipation factor (tan δ) of 0.02 at 25 °C and 1 Hz. From an electric displacement-electric field (D-E) loop study, PMSEMA demonstrated a high discharge energy density of 4.54 J/cm(3) at 283 MV/m, nearly 3 times that of an analogue polymer, poly(methyl methacrylate) (PMMA). However, the hysteresis loss was only 1/3-1/2 of that for PMMA. This study suggests that dipolar glass polymers with large dipole moments and small-sized dipolar side groups are promising candidates for high energy density and low loss dielectric applications.
在本报告中，通过相应甲基丙烯酸酯单体的自由基聚合反应合成了一种偶极玻璃聚合物，聚（甲基丙烯酸2-（甲基磺酰基）乙酯）（PMSEMA）。由于侧链砜基团的偶极矩大（4.25 D）且尺寸小，PMSEMA在1 Hz时于低至-110°C的温度下表现出强烈的γ转变，比其约109°C的玻璃化转变温度低约220°C。由于这种强烈的γ偶极弛豫，玻璃态的PMSEMA样品在25°C和1 Hz时表现出11.4的高介电常数和0.02的低损耗因子（tan δ）。通过电位移-电场（D-E）回线研究，PMSEMA在283 MV/m下显示出4.54 J/cm³的高放电能量密度，几乎是类似聚合物聚甲基丙烯酸甲酯（PMMA）的3倍。然而，滞后损耗仅为PMMA的1/3至1/2。该研究表明，具有大偶极矩和小尺寸偶极侧基的偶极玻璃聚合物是高能量密度和低损耗介电应用的有前途的候选材料。
