Enhancement Of Dielectric Permittivity And Electromechanical Response In Silicone Elastomers: Molecular Grafting Of Organic Dipoles To The Macromolecular Network

• Published in: Advanced functional materials 2011-12, Vol.21 (23), p.4589-4594
• Main Authors: Kussmaul, Björn, Risse, Sebastian, Kofod, Guggi, Waché, Rémi, Wegener, Michael, McCarthy, Denis N., Krüger, Hartmut, Gerhard, Reimund
• Format: Article
• Language: English
• Subjects: dipole grafting; permittivity enhancement; silicone based dielectric elastomer actuators
• ISSN: 1616-301X; 1616-3028
• DOI: 10.1002/adfm.201100884

A novel method is established for permittivity enhancement of a silicone matrix for dielectric elastomer actuators (DEAs) by molecular level modifications of the elastomer matrix. A push‐pull dipole is synthesized to be compatible with the silicone crosslinking chemistry, allowing for direct grafting to the crosslinker molecules in a one‐step film formation process. This method prevents agglomeration and yields elastomer films that are homogeneous down to the molecular level. The dipole‐to‐silicone network grafting reaction is studied by FTIR. The chemical, thermal, mechanical and electrical properties of films with dipole contents ranging from 0 wt% to 13.4 wt% were thoroughly characterized. The grafting of dipoles modifies the relative permittivity and the stiffness, resulting in the actuation strain at a given electrical field being improved by a factor of six. A novel method is established for permittivity enhancement of a silicone matrix for dielectric elastomer actuators by molecular level modifications of the elastomer matrix. A push‐pull dipole is synthesized to be compatible with the silicone crosslinking chemistry, allowing direct grafting to the crosslinker molecules, which results in an improvement of actuation strain by a factor of six.