Piezoelectric and Ferroelectric Properties of Polyurea Thin Films Copolymerized by Vapor Deposition Polymerization of Aliphatic and Aromatic Monomers
Piezoelectric and Ferroelectric Properties of Polyurea Thin Films Copolymerized by Vapor Deposition Polymerization of Aliphatic and Aromatic Monomers
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脂肪族和芳香族单体气相沉积聚合聚脲薄膜的压电和铁电性能
DOI：
10.1143/jjap.35.2199
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发表时间：
1996
影响因子：
1.5
通讯作者：
Eiichi Fukada Eiichi Fukada
中科院分区：
文献类型：
--
作者：
T. Hattori;Yoshikazu Takahashi;Masayuki Iijima Masayuki Iijima;Eiichi Fukada Eiichi Fukada
采用1,9-二氨基壬烷和4,4 ' -二苯基甲烷-二异氰酸酯气相沉积聚合法制备聚脲薄膜。该薄膜具有机械韧性，易于从基材表面分离，类似于脂肪族聚脲薄膜。得到了极化薄膜的压电应力常数e31 （= 4 mC/m2）和热释电常数p3（=8µC/m2 K）。铁电迟滞现象也被观察到。在电场作用下对沉积膜进行退火处理，降低了离子电导率和D-E滞后曲线的残余极化。取向尿素偶极子产生压电性，而离子极化不产生压电性。在-150°C （γ）、-50°C （β）和130°C （α）下，观察到弹性常数c1和介电常数ε3随温度变化的三个弛豫过程，与脂肪族聚氨酯相似。在约100℃之前，压电常数e31保持不变，此时由于α弛豫发生去极化。
Thin films of polyurea were prepared by vapor deposition polymerization of 1,9-diaminononane and 4,4′-diphenyl-methane-diisocyanate. The films were mechanically tenacious and easily separated from the substrate surface, similar to aliphatic polyurea films. Piezoelectric stress constant e31 ( =4 mC/m2) and pyroelectric constant p3 (=8 µ C/m2 K) were obtained for poled films. Ferroelectric hysteresis was also observed. Annealing the deposited film under an electric field decreased the ionic conductivity as well as the residual polarization of the D–E hysteresis curve. The oriented urea dipoles gave rise to piezoelectricity but the ionic polarization did not. Three relaxation processes in the temperature dependence of elastic constant c1 and dielectric constant ε3 were observed at -150° C (γ), -50° C (β), and 130° C (α), similar to those for aliphatic polyureas. The piezoelectric constant e31 remained unchanged until about 100° C, where depolarization took place due to α relaxation.