In this paper, we demonstrate the application of the ionic redox transistor as a reversible shutdown membrane separator (RSMS) in a custom designed Li-ion battery (LIB). The oxidized state corresponds to the OFF state and reduced state corresponds to the ON state of the RSMS in the LIB. It is demonstrated that RSMS reversibly enables and disables the LIB from charging/discharging as it is switched between its reduced (ON) and oxidized (OFF) state, respectively. The operation of the LIB with RSMS is compared with a standard LIB fabricated from identical cathodes and anodes at various C-rates. The specific capacity of the standard LIB is 144, 132, and 50 mAh/g at C/12, C/4, and C/2 rates, respectively. The specific capacity of the LIB with RSMS in the reduced state is 134, 108, and 48 mAh/g at C/12, C/4, and C/2 rates, respectively, showing similar capacity to the standard LIB at all C-rates. The specific capacity of the LIB with RSMS in the oxidized state is 125, 11, and 5 mAh/g at C/12, C/4, and C/2 rates, respectively, demonstrating a capacity decrease compared to the reduced state at all C-rates.

Mechanoluminescent-particulate filled composites have been gaining significant interest for light generation, stress visualization, health monitoring, damage sensing and pressure mapping applications. Previous works on stress-dependence of light emission have modeled emission intensity as a function of macroscopic composite stress. While this approach may suffice from an application point of view, the resulting model may not represent the mechanoluminescence phenomenon accurately. This is because in particulate filled elastomer composites, particulate stresses can be significantly different from matrix and macroscopic stresses, especially in composites with moderate and low filler volume fraction. Experimental difficulty in measuring stresses within micron-sized particles necessitate micromechanical models that can connect macroscale measurements to microscale parameters through material properties. Apart from the material properties of the matrix and the particles, the bonding between the two dissimilar materials at their interface influences the stress transfer significantly. Cohesive zone modeling (CZM) approach defines the interface between particles and matrix as a piecewise linear stiffness element with possible degradation of stiffness beyond a certain strain. CZM provides a convenient way to not only predict particulate stress from macroscopic stress, but also to track interface damage and debonding. In this paper, we demonstrate an experimental technique to obtain cohesive zone parameters for mechanoluminescent-particulate filled elastomer composites, utilizing optical microscopy and Digital Image Correlation (DIC). CZM thus obtained can help predict particulate stresses and aid better modeling of the mechanoluminescence phenomenon. The experimental technique can also be easily adopted for other particulate-filled composites.

Ionomers are a class of polymers which contain a small fraction of charged groups in the polymer backbone. These ionic groups aggregate (termed ionic aggregates) to form temporary cross-links that break apart over the ionic dissociation temperature and re-aggregate on cooling, influencing the mechanical properties of these polymers. In addition to enhanced mechanical properties, some ionomers also exhibit self-healing behavior. The self-healing behavior is a consequence of weakly bonded ionic aggregates breaking apart and re-aggregating after puncture or a ballistic impact. The structure and properties of ionomers have been studied over the last several decades; however, there is a lack of understanding of the influence of an electrostatic field on ionic aggregate morphology. Characterizing the effect of temperature and electric field on the formation and structure of these ionic aggregates will lead to preparation of ionomers with enhanced structural properties. This work focuses on Surlyn 8940 which a poly-ethylene methacryclic acid co-polymer in which a fraction of the carboxylic acid is terminated by sodium. In this work, Surlyn is thermoelectrically processed over its ionic dissociation temperature in the presence of a strong electrostatic field. Thermal studies are performed on the ionomer to study the effect of the thermoelectric processing. It is shown that the application of a thermoelectric field leads to increase in the ionic aggregate order in these materials and reduction in crystal size distribution. Thermal Analysis is performed using a Differential Scanning Calorimeter and the resulting thermogram analysis shows that thermoelectric processing increases the peak temperature and onset temperature of melting by 4 C and 20 C respectively. The peak width at half maximum of the melting endotherm is reduced by 10 C due to thermoelectric processing. This serves as a measure of the increased crystallinity. A parametric study on the effect of field duration and field strength is also performed.

In this article, it is proposed that a membrane with tunable ionic conductivity can be used as a separator between the electrodes of a supercapacitor to both allow normal charge/discharge operation and minimize self-discharge when not in use. It is shown that the redox active conducting polymer PPy(DBS), when polymerized on a porous substrate, will span across the pores of the membrane. PPy(DBS) is also shown to function as an ionic redox transistor, in which the transmembrane ionic conductivity of the polymer membrane is a function of its redox state. The PPy(DBS) ionic redox transistor is applied between the electrodes in a supercapacitor as a smart membrane separator. It is demonstrated that the maximum tunable ionic conductivity of the smart membrane separator is comparable in operation to an industry standard separator at maximum ionic conductivity, with a self-discharge leakage current of ∼0.12mA/cm 2 at 1V. The minimum tunable ionic conductivity of the smart membrane separator is shown to decrease the supercapacitor self-discharge when not in use by a factor of 10, with a leakage current of 0.012mA/cm 2 at 1V. This range of tunable ionic conductivity could lead to the emergence of redox transistor batteries with high energy density and low self-discharge for short and long-term storage applications.

Ionomers are polymers containing a small fraction of charged groups in their polymer backbone. These ionic groups link together to form ionic aggregates which act as temporary cross-links. On heating over the ionic dissociation temperature, these ionic aggregates become mobile in the melt and reaggregate upon cooling. The structure and dynamic behavior of these ionic aggregates gives rise to interesting mechanical and functional properties of the ionomers. Thermal processing of ionomers leads to secondary equilibration of these ionic aggregates. We study this phenomenon of secondary equilibration on application of a thermo-electric field where an electrostatic field is maintained over the ionomer melt. The end goal is to achieve control over the size and distribution of the ionic aggregates by means of an external electric field. The characterization techniques utilized to study the onset of secondary equilibration are UV-Vis Spectroscopy, Differential Scanning Calorimetry, Fourier Transfer Infrared Spectroscopy and Attenuated Total Reflectance analysis. The results indicate that the phenomenon of secondary equilibration is present under the application of a thermoelectric field as indicated by change in spectral and thermal data. A fundamental understanding of the secondary equilibration phenomenon and eventual prevention of the onset of secondary equilibration will lead to long term control of the ionic aggregates by means of an external electric field which will improve the function and utility of these ionomeric materials.

The development of novel characterization techniques is critical for understanding the fundamentals of material systems. Bioinspired systems are regularly implemented but poorly defined through quantitative measurement. In an effort to specify the coupling between multiple domains seen in biologically inspired systems, high resolution measurement systems capable of simultaneously measuring various phenomena such as electrical, chemical, mechanical, or optical signals is required. Scanning electrochemical microscopy (SECM) and shear-force (SF) imaging are nanoscale measurement techniques which examine the electrochemical behavior at a liquid-solid or liquid-liquid interface and simultaneously probe morphological features. It is therefore a suitable measurement technique for understanding biological phenomena. SF imaging is a high resolution technique, allowing for nanoscale measurement of extensional actuation in materials with high signal to noise ratio. The sensing capabilities of SECM-SF techniques are dependent on the characteristics of the micro-scale electrodes (ultramicroelectrodes or UMEs) used to investigate surfaces. Current limitations to this technique are due to the fabrication process which introduces structural damping, reducing the signal produced. Additionally, despite the high cost of materials and processing, contemporary processes only produce a 10% yield. This article demonstrates a UME fabrication process with a 60% yield as well as improved amplitude (250% increase) and sensitivity (210% increase) during SF imaging. This process is expected to improve the signal to noise ratio of SF-based measurement systems. With these improvements, SECM-SF could become a more suitable technique for measuring cell or tissue activity, corrosion of materials, or coupled mechanics of synthetic faradaic materials.

Scanning electrochemical microscopy (SECM) is an electrochemical technique used to measure faradaic current changes local to the surface of a sample. The incorporation of shear force (SF) feedback in SECM enables the concurrent acquisition of topographical data of substrates along with electrochemical measurements. Contemporary SECM measurements require a redox mediator such as ferrocene methanol (FcMeOH) for electrochemical measurements; however, this could prove detrimental in the imaging of biological cells. In this article, nanoscale polypyrrole membranes doped with dodecylbenzene sulfonate (PPy(DBS)) are deposited at the tip of an ultra-microelectrode (UME) to demonstrate a novel modification of the contemporary SECM-SF imaging technique that operates in the absence of a redox mediator. The effect of distance from an insulating substrate and bulk electrolyte concentration on sensor response are examined to validate this technique as a tool for correlated topographical imaging and cation flux mapping. Varying the distance of the PPy(DBS) tipped probe from the substrate in a solution containing NaCl causes a localized change in cation concentration within the vicinity of the membrane due to hindered diffusion of ions from the bulk solution to the diffusion field. The cation transport into the membrane in close proximity to the substrate is low as compared to that in the electrolyte bulk and asymptotically approaches the bulk value at the sense length. At a constant height from the base, changing the bulk NaCl concentration from 5 mM to 10 mM increases the filling efficiency from 35% to 70%. Further, the sense length of this modified electrode in NaCl is about 440 nm which is significantly lower as compared to that of a bare electrode in ferrocene methanol (5–20 μm). It is postulated that this novel technique will be capable of producing high resolution maps of surface cation concentrations, thus having a significant impact in the field of biological imaging.

The transport of monovalent cations across a suspended PPy(DBS) polymer membrane in an aqueous solution as a function of its redox state is investigated. Maximum ion transport is found to occur when PPy(DBS) is in the reduced state, and minimum transport in the oxidized state. No deviation in the dynamics of ion transport based on the direction of the applied electrical field is observed. Additionally, it is found that ion transport rates linearly increased proportional to the state of reduction until a steady state is reached when the polymer is fully reduced. Therefore controlled, bidirectional ion transport is for the first time demonstrated. The effect of aqueous Li + concentration on ion transport in the fully reduced state of the polymer is studied. It is found that ion transport concentration dependence follows Michaelis-Menten kinetics (which models protein reaction rates, such as those forming ion channels in a cell membrane) with an r 2 value of 0.99. For the given PPy(DBS) polymer charge density and applied potential across the membrane, the maximum possible ion transport rate per channel is found to be 738 ions per second and the Michaelis constant, representing the concentration at which half the maximum ion transport rate occurs, is 619.5mM.

This research introduces an integrated vibration energy harvester and electrochemical energy storage device that can effectively convert ambient vibrations directly into stored electrochemical energy. The electrochemical energy storage device is an electrical double layer capacitor (EDLC) with an ionic redox transistor as its membrane separator. This ‘ smart ’ membrane separator directly rectifies the electrical energy generated by the transduction from the nonlinear energy harvester, creating an ionic polarization across the membrane separator for storage. This electrochemical gradient can be subsequently used for powering sensor electronics as required in various applications, including structural condition monitoring. The alternating voltage developed by the energy harvester (+/−5V around 100 Hz) is connected to an aqueous supercapacitor fabricated from nanofibrous carbon paper electrodes and a polypyrrole-based (PPy(DBS)) smart membrane separator. A potential below −400mV from the energy harvester applied to the supercapacitor turns the smart membrane separator ‘ON’ and results in a unidirectional ionic current of Li+ ions. As the potential developed by the harvester cycles above ∼50 mV, the membrane separator switches ‘OFF’ and prevents the discharge of the rectified current. This leads to a continuous polarization of ions towards electrical fields relevant for powering electronics. This article is the first description and demonstration of an energy harvesting and storage system that can directly convert the electrical energy from a vibration energy harvester into electrochemical energy without the use of passive circuit components for power rectification.

PPy-based membranes exchange ions with electrolyte through reversible redox processes and hence are best suited as electrodes for batteries and super capacitors. The energy density of batteries and super capacitors are dependent on the specific capacitance of the conducting polymer and can be represented through a mechanistic model for ion transport. Through this model, the specific capacitance of polypyrrole-based membranes is shown to be dependent on the number of accessible redox sites at the electrolyte-polymer interface. The accessibility of redox sites at the electrolyte-polymer interface can be increased by controlling the morphological properties and distribution of dopant in the polymer backbone. Thus, by nanostructuring and by controlling the distribution of the dopant in the polymer, we have shown that the capacitance of PPy-based membranes can be increased to 490 F.g −1 for a 50 mV.sec −1 scan rate and 0.6 g.cm −2 specific mass. Despite this value of specific capacitance being the highest reported for PPy-based membranes to date, it is estimated that only 69% of active redox sites are used for ion storage and hence can be increased further. Maximizing specific capacitance requires an understanding of spatial distribution of redox sites in the polymer backbone and its corresponding chemoelectrical activity. In order to generate a spatial map of ion storage in PPy-based membranes, this article presents for the first time a shear-force (SF) based topography imaging and scanning electrochemical microscopy (SECM) imaging of the PPy(DBS) under reduced and oxidized conditions. From a correlated topography and chemoelectrical activity of PPy-based membrane, the data shows the availability of redox sites in the polymer and it is projected that this result will enhance the design and nanostructuring of PPy-based membranes and distribution of dopant in the backbone.

Charge motion in internal combustion engines is controlled by valves located near the engine ports in the intake path. The valve bodies are obstructions in the air-flow path and are a source of inefficiencies in the engine over its entire operating load. In order to achieve charge motion control without the use of valves, this research investigates the use of synthetic jet actuators to perform swirl and tumble of the air mass entering the cylinder. The purpose of this research is to design, test, and characterize a synthetic jet actuator, and determine the feasibility of using synthetic jet actuators in automotive air-intake systems. The accomplished work to date has led to geometrical optimization, fabrication of a prototype, and experimental investigation for determining jet velocities. The geometrical optimization of synthetic jets has led to a device with a thinner profile that allows it to be embedded in structures with thin (< 5mm) cross-sections and hence we refer to our synthetic jets as surface synthetic jets. It is shown here that air exiting the surface synthetic jets achieves sustained peak velocities well above 125 m/s. A variational principles-based approach is used to model the frequency response of the piezoelectric diaphragm, coupled with the lumped-parameter model for the surface synthetic jets and simulated using MATLAB Simulink ® . The results of this model are validated with experimental results and extended to design charge motion control devices. From these results, it is anticipated that these surface synthetic jet actuators can achieve charge motion control using a radial array of surface synthetic jet actuators distributed around the intake runner.

Selective rejection of dissolved salts in water is achieved by large pressure gradient driven flows through tortuous structures and cylindrical nanopores. The flow rate through the membrane is dependent on the area of the membrane and pressure gradient that can be sustained by the membrane. The electrical power required for generating large pressure gradients increases the operational cost for desalination units and limits application of contemporary technologies in a wide variety of applications. Due to this limitation, small scale operation of these desalination systems is not economical and portable. Further, recently proposed desalination systems using carbon nanotubes and nanofluidic diodes have limited lifetime due to clogging and fouling from contaminants in feed water. In order to develop a desalination system that is not limited by cost, scale of operation and application, an active nanopore membrane that uses multiphysics interactions in a surface-functionalized hyperboloidal nanopore is developed. An active nanopore is a shape-changing hyperboloidal pore that is formed in a rugged electroactive composite membrane and utilizes coupled electrostatic, hydrodynamic and mechanical interactions due to reversible mechanical oscillations between the charged pore walls and dissolved ions in water for desalination. This novel approach takes advantage of the shape of the pore to create a pumping action in the hyperboloidal channel to selectively transport water molecules. In order to demonstrate the applicability of this novel concept for water desalination, the paper will use a theoretical model to model the ion rejection properties and flow rate of purified water through an active nanoporous membrane. This article examines the effect of the geometry of the nanopore and frequency of operation to reject dissolved ions in water through a multiphysics model. It is estimated that the neck diameter of the active nanopores is the most dominant geometrical feature for achieving ion rejection, and the flux linearly increases with the frequency of operation (between 2–50Hz). The threshold neck diameter of the nanopore required for achieving rejection from multiphysics simulation is observed to be 100nm. The flux through the membrane decreases significantly with decreasing diameter and becomes negligible at 10nm effective neck diameter.

Recent studies of polypyrrole (PPy) electrodes have been increasing the interfacial surface area in order to increase electrochemical performance. We present a novel method of electropolymerizing PPy doped with dodecylbenzenesulfonate (DBS) referred to as biotemplating. A biotemplated conducting polymer utilizes phospholipid vesicles in order to form a three dimensional structure with a sponge-like shape. The vesicles, measuring 1–2 μm in diameter, are added in situ with the polymerization solution. They become enveloped while maintaining their structure during electropolymerization of PPy(DBS). The result of this structure is a significant increase in surface area compared to current techniques. There are several advantages in using biotemplated conducting polymers as battery electrodes. Compared to a planar PPy(DBS) membrane, biotemplated PPy(DBS) membranes have a roughly 50% increased storage capacity. There is an expected reduction in volumetric expansion during ion ingress/egress into the polymer backbone. This reduction would result in decreased fatigue loading and improving cyclability. Further, biotemplated PPy(DBS) membranes can be fabricated into thin structures with increased flexibility, allowing them to be rolled into various packaging sizes. In this article, the charge density of a biotemplated PPy(DBS) membrane as a function of charging and discharging currents is compared to a planar PPy(DBS) membrane. The structural enhancement offers systemic advantages by providing higher volumetric energy density and decreased fatigue loading for applications involving conducting polymer electrodes.

Conducting polymers undergo volumetric expansion through redox-mediated ion exchange with its electrolytic environment. The ion transport processes resulting from an applied electrical field controls the conformational relaxation in conducting polymer and regulates the generated stress and strain. In the last two decades, significant contributions from various groups have resulted in methods to fabricate, model and characterize the mechanical response of conducting polymer actuators in bending mode. An alternating electrical field applied to the polymer electrolyte interface produces the mechanical response in the polymer. The electrical energy applied to the polymer is used by the electrochemical reaction in the polymer backbone, for ion transport at the electrolyte-polymer interface and for conformational changes to the polymer. Due to the advances in polymer synthesis, there are multitudes of polymer-dopant combinations used to design an actuator. Over the last decade, polypyrrole (PPy) has evolved to be the most common conducting polymer actuator. Thin sheets of polymer are electrodeposited on to a substrate, doped with dodecylbezenesulfonate (DBS-) and microfabricated into a hermetic, air operated cantilever actuator. The electrical energy applied across the thickness of the polymer is expended by the electrochemical interactions at the polymer-electrolyte interface, ion transport and electrostatic interactions of the backbone. The widely adopted model for designing actuators is the electrochemically stimulated conformational relaxation (ESCR) model. Despite these advances, there have been very few investigations into the development of a constitutive model for conducting polymers that represent the input-output relation for chemoelectromechanical energy conversion. On one hand, dynamic models of conducting polymers use multiphysics-based non-linear models that are computationally intensive and not scalable for complicated geometries. On the other, empirical models that represent the chemomechanical coupling in conducting polymers present an over-simplified approach and lack the scientific rigor in predicting the mechanical response. In order to address these limitations and to develop a constitutive model for conducting polymers, its coupled chemomechanical response and material degradation with time, we have developed a constitutive model for polypyrrole-based conducting polymer actuator. The constitutive model is applied to a micron-scale conducting polymer actuator and coupling coefficients are expressed using a mechanistic representation of coupling in polypyrrole (dodecylbenzenesulfonate) [PPy(DBS)].

Conducting polymers are ionic active materials that can perform electro-chemo-mechanical work through redox reactions. The electro-chemo-mechanical coupling in these materials has been successfully applied to develop various application platforms (actuation systems, sensor elements and energy storage devices (super capacitors, battery electrodes)). Similarly, bioderived membranes are ionic active materials that have been demonstrated as actuators, sensors and energy harvesting devices. Bioderived membranes offer significant advantages over synthetic ionic active materials in energy conversion and the scientific community has put forward various system level concepts for application in engineering applications. The biological origins of these material systems and their subsequent mechanical, electrical and thermal properties have served as a key deterrent in applications. This article proposes a novel architecture that combines a conducting polymer and a bioderived membrane into an integrated material system in which the charge gradients generated from a biochemical reaction is stored and released in the conducting polymer through redox reactions. This paper discusses the fabrication and topographical characterization of the integrated bioderived-conducting polymer membrane nanostructures. The prototype comprises of an organized array of fluid-filled three-dimensional containers with an integrated membrane shell that performs energy conversion and storage owing to its multi-functional microstructure. The bioderived membrane is self-assembled into a hollow spherical container from synthetic membranes or bilayer lipid membranes with proteins and the conducting polymer membrane forms a wrapper around this container resulting in a three-dimensional assembly.

Conducting polymer actuators and sensors utilize electrochemical reactions and associated ion transport at the polymer-electrolyte interface for their engineering function. Similarly, a bioderived active material utilizes ion transport through a protein and across a bilayer lipid membrane for sensing and actuation functions. Inspired by the similarity in ion transport process in a bilayer lipid membrane (BLM) and conducting polymers, we propose to build an integrated ionic device in which the ion transport through the protein in the bilayer lipid membrane regulates the electrolytic and mechanical properties of the conducting polymer. This article demonstrates the fabrication and characterization of a DPhPC planar BLM reconstituted with alamethicin and supported on a polypyrrole bridge measuring 100 μm × 500 μm and formed across micro-fabricated gold pads. The assembly is supported on silicon dioxide coated wafers and packaged into an electronic-ionic package for electrochemical characterization. The various ionic components in the integrated ionic device are characterized using electrical impedance spectroscopy (EIS), cyclic voltammetry (CV), and chronoamperometry (CA) measurements. The results from our experimental studies demonstrate the procedure to fabricate a rugged electro active polymer supported BLM that will serve as a platform for chemical, bioelectrical sensing and VOC detection.

Conducting polymers possess similarity in ion transport function to cell membranes and perform electro-chemo-mechanical energy conversion. In an in vitro setup, protein-reconstituted bilayer lipid membranes (bioderived membranes)perform similar energy conversion and behave like cell membranes. Inspired by the similarity in ionic function between a conducting polymer membrane and cell membrane, this article presents a thin-film laminated membrane in which alamethicin-reconstituted lipid bilayer membrane is supported on a polypyrrole membrane. Owing to the synthetic and bioderived nature of the components of the membrane, we refer to the laminated membrane as a hybrid bioderived membrane. In this article, we describe the fabrication steps and electrochemical characterization of the hybrid membrane. The fabrication steps include electropolymerization of pyrrole and vesicle fusion to result in a hybrid membrane; and the characterization involves electrical impedance spectroscopy, chronoamperometry and cyclic voltammetry. The resistance and capacitance of BLM have the magnitude of 4.6×10 9 Ω-cm 2 and 1.6×10 −8 F/cm 2 .The conductance of alamethicin has the magnitude of 6.4×10 −8 S/cm 2 . The change in ionic conductance of the bioderived membrane is due to the electrical field applied across alamethicin, a voltage-gated protein and produces a measurable change in the ionic concentration of the conducting polymer substrate.

Current water desalination technologies such as reverse osmosis (RO) and nanofiltration (NF) use tortuous structures and cylindrical nanopores to reject salts by size exclusion. The selective rejection of salts dissolved in water using nanopores requires large pressure gradients across the membranes to produce reasonable flow rates. The electrical power required for generating large pressure gradients increases the operational cost for desalination and limits its application as portable units in small communities and in third-world countries. Further, recently proposed desalination methods using carbon nanotubes and nanofluidic diodes have limited lifetime due to clogging and fouling from contaminants in feed water. Thus, existing or evolving technologies are expensive, bulky and not practical where it is needed the most. In order to develop a desalination system that is not limited by the disadvantages of existing systems, this article investigates the feasibility of a novel active nanopore membrane with superior ion rejection and water transport properties. An active nanopore is a shape-changing hyperboloidal pore that is formed in a rugged electroactive composite membrane and utilizes coupled electrostatic, hydrodynamic and mechanical interactions due to reversible mechanical oscillations between the charged pore walls and dissolved ions in water for desalination. This novel approach takes advantage of the shape of the pore to create a pumping action in the hyperboloidal channel to selectively transport water molecules. In order to demonstrate the applicability of this novel concept for water desalination, the paper will use a theoretical model to model the ion rejection properties and flow rate of salt-free water through an active nanoporous membrane.

Biological ion transport has inspired recent developments in smart materials. The work by Leo and co-workers, Bailey and co-workers has demonstrated the feasibility to design engineered systems using biological ion transporters. The biological and bio-inspired systems utilize ion transport across a barrier membrane for energy conversion. Among smart materials, ionic-active materials demonstrate electromechanical coupling using ion transport across the thickness of the polymer. Inspired by the resemblance between ionic interaction in a conducting polymer and biological membranes, this paper presents a novel actuation mechanism that uses ion transport through a biological membrane to produce shape changes in a conducting polymer actuator. This paper presents the basic architecture, the physics of transduction and analysis of extensional and bending actuation in the hybrid bio-polymer actuator. An extensional actuator of size 1 cm × 1 cm × 1 μm is theoretically found to generate 135 mPa of blocked stress. A bimorph bending actuator of dimensions 10 mm × 1 mm × 2 μm is theoretically found to produce a free-displacement of 0.5 mm using biochemical gradients.

This article continues our work to develop magnetoelectric materials as self-sensing actuators. Our research is directed at developing a two-segment cantilever device with closed-loop control. The actuator under study is fabricated as a laminated composite of the magnetostrictive material Iron-Gallium (Galfenol) and a Lead-Zirconate-Titanate piezoelectric material (PZT-5H). The mechanical and electrical characteristics of a single-segment cantilever are modeled using the equation of motion developed from variational principles in earlier work and are compared with experimental data from other groups. Additionally, parametric analysis is performed to determine the effect of varying the thickness fraction of the piezoelectric layer on the frequency response characteristics of the actuator. When applied to the dynamic behavior of the actuator, the model predicts behavior that closely resembles experimental results published by other groups. Parametric analysis of the piezoelectric layer thickness fraction indicates that the design of a magnetoelectric cantilever self-sensing actuator can be optimized by varying the thickness fraction.