TY  - JOUR
A1  - Farhan, Muhammad
A1  - Chaudhary, Deeptangshu
A1  - Nöchel, Ulrich
A1  - Behl, Marc
A1  - Kratz, Karl
A1  - Lendlein, Andreas
T1  - Electrical actuation of coated and composite fibers based on poly[ethylene-co-(vinyl acetate)]
JF  - Macromolecular materials and engineering
N2  - Robots are typically controlled by electrical signals. Resistive heating is an option to electrically trigger actuation in thermosensitive polymer systems. In this study electrically triggerable poly[ethylene-co-(vinyl acetate)] (PEVA)-based fiber actuators are realized as composite fibers as well as polymer fibers with conductive coatings. In the coated fibers, the core consists of crosslinked PEVA (cPEVA), while the conductive coating shell is achieved via a dip coating procedure with a coating thickness between 10 and 140 mu m. The conductivity of coated fibers sigma = 300-550 S m(-1) is much higher than that of the composite fibers sigma = 5.5 S m(-1). A voltage (U) of 110 V is required to heat 30 cm of coated fiber to a targeted temperature of approximate to 65 degrees C for switching in less than a minute. Cyclic electrical actuation investigations reveal epsilon '(rev) = 5 +/- 1% reversible change in length for coated fibers. The fabrication of such electro-conductive polymeric actuators is suitable for upscaling so that their application potential as artificial muscles can be explored in future studies.
KW  - artificial muscles
KW  - fiber actuators
KW  - resistive heating
KW  - shape‐memory polymer actuators
KW  - soft robotics
Y1  - 2020
U6  - https://doi.org/10.1002/mame.202000579
SN  - 1438-7492
SN  - 1439-2054
VL  - 306
IS  - 2
PB  - Wiley-VCH
CY  - Weinheim
ER  - 
TY  - JOUR
A1  - Razzaq, Muhammad Yasar
A1  - Behl, Marc
A1  - Heuchel, Matthias
A1  - Lendlein, Andreas
T1  - Matching magnetic heating and thermal actuation for sequential coupling in hybrid composites by design
JF  - Macromolecular rapid communications
N2  - Sequentially coupling two material functions requires matching the output from the first with the input of the second function. Here, magnetic heating controls thermal actuation of a hybrid composite in a challenging system environment causing an elevated level of heat loss. The concept is a hierarchical design consisting of an inner actuator of nanocomposite material, which can be remotely heated by exposure to an alternating magnetic field (AMF) and outer layers of a porous composite system with a closed pore morphology. These porous layers act as heat insulators and as barriers to the surrounding water. By exposure to the AMF, a local bulk temperature of 71 degrees C enables the magnetic actuation of the device, while the temperature of the surrounding water is kept below 50 degrees C. Interestingly, the heat loss during magnetic heating leads to an increase of the water phase (small volume) temperature. The temperature increase is able to sequentially trigger an adjacent thermal actuator attached to the actuator composite. In this way it could be demonstrated how the AMF is able to initiate two kinds of independent actuations, which might be interesting for robotics operating in aqueous environments.
KW  - artificial muscles
KW  - magnetosensitivity
KW  - nanocomposites
KW  - soft actuators
Y1  - 2019
U6  - https://doi.org/10.1002/marc.201900440
SN  - 1022-1336
SN  - 1521-3927
VL  - 41
IS  - 1
PB  - Wiley-VCH
CY  - Weinheim
ER  -