writer：Dong Xiang,? Jingjing He,? Tongtong Cui,§ Li Liu,? Qi Song Shi,? Lan Chao Ma,? and Yongri Liang
keywords：介电弹性体，聚氨酯弹性体，结构与性能关系
source：期刊
Issue time：2018年

Understanding the relationship between multiphase structure and electromechanical property of thermoplastic

dielectric elastomers is significantly important in the developments of high-performance and novel dielectric elastomers. In this

work, we fabricated a series of aliphatic polyurethane elastomers (PUEs) based on hydroxyl-terminated butadiene-acrylonitrile

copolymer (HTBN), hexamethylene diisocyanate (HDI), and various lengths of linear aliphatic diols and investigated effect of

their microstructure and morphology on dielectric and electromechanical properties. The FTIR, WAXS, SAXS, and viscoelastic

AFM results showed that the PUEs existed in crystalline phase, hard domain (HD) and soft domain (SD) phases composed

HD-rich region and few HDs and SD composted SD-rich region by crystallization and microphase separation. Also, the crystal

morphology and crystallinity of PUEs are strongly influenced by the length of chain extender due to the chain extender adopting

various conformations by hydrogen bonding. The mechanical and electric fields induced responses of segment motions in PUEs

at below room temperature were relative to the constrained SS motions from HD-rich and SD-rich regions. The electric field

induced strain of PUEs was actuated by both Maxwell stress and electrostriction effect, of which contribution of electrostriction

effect was above 64% in total actuation strain. In addition, we found that the effect of electrostriction on the actuation strain

played an important role in improving the actuation strain of PUEs at lower electric field. Our results showed that the dielectric

and electromechanical properties of PUEs can be adjusted by controlling the crystallization and microphase separation.