TY  - JOUR
A1  - Kussmaul, Bjoern
A1  - Risse, Sebastian
A1  - Kofod, Guggi
A1  - Wache, Remi
A1  - Wegener, Michael
A1  - McCarthy, Denis N.
A1  - Krüger, Hartmut
A1  - Gerhard, Reimund
T1  - Enhancement of dielectric permittivity and electromechanical response in silicone elastomers molecular grafting of organic dipoles to the macromolecular Network
JF  - Advanced functional materials
N2  - 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.
KW  - dipole grafting
KW  - silicone based dielectric elastomer actuators
KW  - permittivity enhancement
Y1  - 2011
U6  - https://doi.org/10.1002/adfm.201100884
SN  - 1616-301X
VL  - 21
IS  - 23
SP  - 4589
EP  - 4594
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Kussmaul, Björn
A1  - Risse, Sebastian
A1  - Wegener, Michael
A1  - Kofod, Guggi
A1  - Krüger, Hartmut
T1  - Matrix stiffness dependent electro-mechanical response of dipole grafted silicones
JF  - Smart materials and structures
N2  - The properties of dielectric elastomer actuators can be optimized by modifying the dielectric or mechanical properties of the dielectric elastomer. This paper presents the simultaneous control of both dielectric and mechanical properties, in a silicone elastomer network comprising cross-linker, chains and grafted molecular dipoles. Chains with two different molecular weights were each combined with varying amounts of grafted dipole. Chemical and physical characterization showed that networks with stoichiometric control of cross-linking density and permittivity were obtained, and that longer chain lengths resulted in higher electrical field response due to the reduction in cross-linking density and correspondingly in mechanical stiffness. Both actuation sensitivities were enhanced by 6.3 and 4.6 times for the short and long chain matrix material, respectively.
Y1  - 2012
U6  - https://doi.org/10.1088/0964-1726/21/6/064005
SN  - 0964-1726
VL  - 21
IS  - 6
PB  - IOP Publ. Ltd.
CY  - Bristol
ER  -