The Ionic Polymer-Metal Composite (IPMC) for flexible hydrodynamic propulsor blades can provide many new opportunities in the naval platforms, especially in developing robotic unmanned vehicles for both surveillance and combat. IPMC materials are quietly operational since they have no vibration causing components, i.e. gears, motors,
shafts, and etc. For small Autonomous Underwater Vehicles (AUV), these features are truly attractive due to limited space. Also, IPMCs are friendly to solid-state electronics with digital programming capabilities. Active control is thus possible. Another advantage of these materials should be recognized from the fact that they can be operational in a self-oscillatory manner. There are several issues that still need to be addressed such as propulsor
design, testing, robotic control as well as theoretical modeling of the appropriate design. In this effort, IPMC is investigated for propulsor blades applications in NaCl solution and a propulsor model with a robust control scheme is explored. An analytical model of a segmented IPMC propulsor was formulated to be used as a building block for furthering the model to adequately accommodate the relaxation behavior of IPMCs and for describing the dynamics of the flexible IPMC bending actuator.
It has been observed that the Ionic Polymer-Metal Composite (IPMC) is both inherently resistive and capacitive. This allows for the material to be modeled using an equivalent RC circuit to describe the charging/discharging behavior associated with the IPMC. Typically, the model includes two resistors and two capacitors, which will primarily account for the effective electrodes on the surface of the IPMC (top and bottom). There will also be a resistor placed between the two RC circuits to account for material between the electrodes and the resistance due to ion migration through polymer matrix. In this paper we report our recent effort to extend such a model to accommodate a multi-layer IPMCs a swell as inter-digitated electrodes. As expected the observed electric characteristics of an IPMC subjected to an electric field is highly non-linear. This is believed to be due primarily to the particle electrodes on the IPMC surface, which is inherently both captive and resistive due to particle seperation and density. The advantage of using such a model is to realize the capacitive and resistive effect and use them for multi-layer configuration. We also present typical experimental data.
There is currently a need for actuators that will operate in low temperature environments. Ideally, the Ionic Polymer-Metal Composite (IPMC) actuator should be able to operate in a temperature range of 0 to -50 degrees Celsius. IPMC can be a useful solution for cold temperature actuation because of its soft actuation with relatively low input voltages while the base polymeric material can undergo a multiple phase transition below 0 degree Celsius. Due to the complex nature of the material, the physics become increasingly difficult to predict in a low temperature environment on account of the IPMC/s dependency upon water and/or tightly bounded cations/water for effective actuation. In this paper, we provide experimental data and an apparatus that is constructed to obtain force feedback from an IPMC sample that is placed in a subzero chamber. The electric/thermal/mechanical data for this experiment is presented and assumptions are made and explained regarding the nature of the cold temperature actuation. Also, analytical tool used is DSC to reveal the true water structures in the IPMC. It should be noted that the use of IPMC in the temperature range of -50 to 0 degree Celsius is of importance for a number of engineering applications.
Nanocomposites are a new class of composites which are typically nanoparticle-filled polymers. One promising kind of nanocomposite is clay-based and polymer-layered silicates nanocomposites because the starting clay materials are naturally abundant and, also, their intercalation chemistry is well understood at the present time. A certain clay, Montmorillonite (MxAl4- xMgx)Si8O20$(OH4 has two-dimensional layers of their crystal structure lattice where the layer thickness is around 1 nm with the lateral dimension of approximately 30 nm to a few microns. These layers organize themselves to form stacks, so-called the Gallery through a van der Walls gap in between them. In this work, Montmorillonite (MMT) was modified by a cationic surfactant so as to lower its surface energy significantly. Such a process gave rise to favorable intercalation of nanoparticles within the galleries. The obtained XRD patterns and TEM images indicate that the silicate layers are completely and uniformly dispersed (nearly exfoliated) in a continuous polymer matrix of Nafion that has been successfully used as a starting material of ionic polymer-metal composites (IPMC's).
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.