A streaming potential method for modeling the electromechanical responses due to imposed deformation of ionic
polymer transducers (IPTs) is presented. It has been argued that imperfect ion pairing results in the availability of free
counterions within the hydrophilic regions, thereby resulting in the presence of an electrolyte within these regions in the
hydrophobic polymer matrix. When there is a net relative motion of this electrolyte with respect to the electrode, a
streaming potential should result. It is hypothesized that a streaming potential mechanism within the electrode regions
should be able to predict sensing responses for all modes of deformation. Based on a recently introduced parallel waterchannel
morphology in Nafion® membrane, this model successfully addresses the physics of sensing in IPT bending. A
linear relationship between the tip deflection of an IPT cantilever beam and the current generated in the IPT is achieved.
The result trends show a good agreement with the experimental measurements. While this work studies the bending
mode, it is able to be adapted for the other three sensing modes.
While the acidic polymer electrolyte membrane (PEM) Nafion has garnered considerable attention, the active response
of basic PEMs offers another realm of potential applications. For instance, the basic PEM Selemion is currently being
considered in the development of a CO<sub>2</sub> separation prototype device to be employed in coal power plant flue gas. The
mechanical integrity of this material and subsequent effects in active response in this harsh environment will become
important in prototype development. A multiscale modeling approach based on rotational isomeric state theory in
combination with a Monte Carlo methodology may be employed to study mechanical integrity. The approach has the
potential to be adapted to address property change of any PEM in the presence of foreign species (reinforcing or
poisoning), as well as temperature and hydration variations. The conformational characteristics of the Selemion
polymer chain and the cluster morphology in the polymer matrix are considered in the prediction of the stiffness of
Selemion in specific states.
Rotational isomeric state (RIS) theory has long been used to predict mechanical response trends in polymeric materials
based on the polymer chain conformation it addresses. Successful adaptation of this methodology to the prediction of
elastic moduli would provide a powerful tool for guiding ionomer fabrication. Recently, a multiscale modeling approach
to the material stiffness prediction of ionic polymer has been developed. It applies traditional RIS theory in combination
with a Monte Carlo methodology to develop a simulation model for polymer chain conformation on a nanoscopic level.
A large number of end-to-end chain lengths are generated from this model and are then used to estimate the probability
density function which is used as an input parameter to enhance existing energetics-based macroscale models of ionic
polymer for material stiffness prediction. This work improves this Mark-Curro Monte Carlo methodology by adapting
the RIS theory in a way to overcome early terminations of polymer chain while simulating the conformation of polymer
chains and thus obtains more realistic values of chain length. One solvated Nafion<sup>®</sup> case is considered. The probability
density function for chain length is estimated with the most appropriate Johnson family method applied. The stiffness
prediction is considered as a function of total molecular weight.