Molecular Dynamics (MD) techniques have been used to study the structure and dynamics of a model system of an
interpenetrating polymer (IPN) network for actuator devices. The systems simulated were generated using a Monte
Carlo-approach, and consisted of poly(ethylene oxide) (PEO) and poly(butadiene) (PB) in a 80-20 percent weight ratio
immersed into propylene carbonate (PC) solutions of LiClO4. The total polymer content was 32%, in order to model
experimental conditions. The dependence of LiClO4 concentration in PC has been studied by studying five different
concentrations: 0.25, 0.5, 0.75, 1.0 and 1.25 M. After equilibration, local structural properties and dynamical features
such as phase separation, coordination, cluster stability and ion conductivity were studied. In an effort to study the
conduction processes more carefully, external electric fields of 1×106 V/m and 5×106 V/m has been applied to the
simulation boxes. A clear relationship between the degree of local phase separation and ion mobility is established. It is
also shown that although the ion pairing increases with concentration, there are still significantly more potential charge
carriers in the higher concentrated systems, while concentrations around 0.5-0.75 M of LiClO4 in PC seem to be
favorable in terms of ion mobility. Furthermore, the anions exhibit higher conductivity than the cations, and there are
tendencies to solvent drag from the PC molecules.
This paper discusses the design and the realization of a prototype magnetic resonance imaging (MRI)-compatible tactile display device based on interpenetrated networks of conductive polymer actuators shaped into a pastille form. The electro-active polymers are investigated as an alternative solution to conceive tactile displays dedicated to fMRI studies. The tactile display is a 3×3 matrix- arranged pin; each pin is actuated independently and linked with the pastille-shaped IPN-CP actuator through a unilateral contact without intermediary motion or force amplification mechanism. All the technical aspects are discussed and presented.
This paper presents a new way to design and fabricate ionic polymer actuators showing a linear movement in air. This is done by use of an original shaping during the polymerization step. The possible solutions for linear actuation were tested with a simulation technique that has been designed on purpose, which helped us to choose the best. By means of very unusual fabrication techniques that were required for that, actuators were made following this principle and their performances were measured.