Triblock Copolymer Organogels as High-Performance Dielectric Elastomers

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• 作者：Ravi Shankar ; Arjun K. Krishnan ; Tushar K. Ghosh ; Richard J. Spontak
• 刊名：Macromolecules
• 出版年：2008
• 出版时间：August 26, 2008
• 年：2008
• 卷：41
• 期：16
• 页码：6100-6109
• 全文大小：343K
• 年卷期：v.41,no.16(August 26, 2008)
• ISSN：1520-5835

文摘

Block copolymers and nanostructured materials derived therefrom are becoming increasingly ubiquitous in a wide variety of (nano)technologies. Recently, we have demonstrated that triblock copolymer organogels composed of physically cross-linked copolymer networks swollen with a midblock-selective solvent exhibit excellent electromechanical behavior as dielectric elastomers. In-plane actuation of such organogels, collectively referred to as electroactive nanostructured polymers (ENPs) to reflect the existence of a self-organized copolymer morphology, is attributed to the development of an electric-field-induced surface-normal Maxwell stress. In this study, we examine the composition and molecular weight dependence of the electromechanical properties afforded by organogels prepared from poly[styrene-b-(ethylene-co-butylene)-b-styrene] (SEBS) triblock copolymers selectively swollen with EB-compatible aliphatic oligomers. These materials undergo ultrahigh actuation displacement at significantly reduced electric fields relative to previously reported dielectric elastomers and possess electromechanical coupling efficiencies, which relate the conversion from electrical input to mechanical output, greater than 90%. The design of ENPs with broadly tunable electromechanical properties represents an attractive route to responsive materials for advanced engineering, biomimetic and biomedical applications.