Dr. Barbar J. Akle Profile

Dr. Barbar J. Akle

Associate Professor at Lebanese American Univ

SPIE Involvement:

Conference Program Committee | Author

Publications (27)

Proceedings Article | 19 March 2019 Presentation + Paper

Ionic buoyancy engines: finite element modeling and experimental validation

James Akl, Fadi Alladkani, Barbar Akle

Proceedings Volume 10966, 109661E (2019) https://doi.org/10.1117/12.2515390

KEYWORDS: Electrodes, Finite element methods, Data modeling, Fluid dynamics, Thermodynamics, Diffusion, Sensors, Water, Ions, Chemical elements

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Proceedings Article | 26 April 2017 Presentation + Paper

Modeling and experimentally characterizing ionic buoyancy engines

Barbar Akle, Jalal Nasser, Ahmad Hijazi

Proceedings Volume 10163, 1016318 (2017) https://doi.org/10.1117/12.2261793

KEYWORDS: Electrodes, Biomimetics, Sensors, Ions, Chemistry, Diffusion, Silver, Energy efficiency, Mechanical engineering, Systems modeling

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Proceedings Article | 15 April 2016 Presentation + Paper

Design and manufacturing of an array of micro IPMC hair-like sensors

Barbar Akle, Charbel Tawk, Elio Challita

Proceedings Volume 9798, 979816 (2016) https://doi.org/10.1117/12.2220776

KEYWORDS: Sensors, Manufacturing, Design for manufacturability, Polymers, Metals, Electrodes, Carbon, Platinum, Sodium, Polymeric sensors

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Proceedings Article | 1 April 2015 Paper

Development and characterization of an IPMC hair-like transducer

Barbar Akle, Elio Challita, Nady Khairalah

Proceedings Volume 9430, 94300H (2015) https://doi.org/10.1117/12.2087432

KEYWORDS: Sensors, Transducers, Electrodes, Carbon, Platinum, Manufacturing, Sodium, Ear, Ions, Lamps

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Proceedings Article | 26 March 2014 Paper

An experimental and numerical approach to understand the effect of the IPMC composition on its sensing and energy harvesting behavior

Barbar Akle, Reef Khairallah, Elio Challita

Proceedings Volume 9056, 90560R (2014) https://doi.org/10.1117/12.2046429

KEYWORDS: Electrodes, Sensors, Particles, Polymers, Energy harvesting, Transducers, Electroactive polymers, Physics, Composites, Data modeling

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Proceedings Article | 8 March 2014 Paper

Actuation and buckling effects in IPMCs

Paola Nardinocchi, Matteo Pezzulla, Barbar Akle, Margarita Guenther, Thomas Wallmersperger

Proceedings Volume 9056, 90560K (2014) https://doi.org/10.1117/12.2044470

KEYWORDS: Electrodes, Polymers, Ions, Metals, Transducers, Electroluminescent displays, Actuators, Energy harvesting, 3D modeling, Calibration

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Proceedings Article | 9 April 2013 Paper

Finite element modeling of the sensing and energy harvesting performance in ionic polymer metal composites

Barbar Akle, Wassim Habchi

Proceedings Volume 8687, 86870G (2013) https://doi.org/10.1117/12.2012406

KEYWORDS: Electrodes, Sensors, Particles, Polymers, Transducers, Diffusion, Dielectrics, Ions, Finite element methods, Composites

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Proceedings Article | 4 April 2012 Paper

Biologically inspired highly efficient buoyancy engine

Barbar Akle, Wassim Habchi, Rita Abdelnour, John Blottman, Donald Leo

Proceedings Volume 8339, 83390O (2012) https://doi.org/10.1117/12.916075

KEYWORDS: Electrodes, Ions, Sensors, Water, Modulation, Bladder, Silver, Distributed computing, Organisms, Ion exchange

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Undersea distributed networked sensor systems require a miniaturization of platforms and a means of both spatial and temporal persistence. One aspect of this system is the necessity to modulate sensor depth for optimal positioning and station-keeping. Current approaches involve pneumatic bladders or electrolysis; both require mechanical subsystems and consume significant power. These are not suitable for the miniaturization of sensor platforms. Presented in this study is a novel biologically inspired method that relies on ionic motion and osmotic pressures to displace a volume of water from the ocean into and out of the proposed buoyancy engine. At a constant device volume, the displaced water will alter buoyancy leading to either sinking or floating. The engine is composed of an enclosure sided on the ocean's end by a Nafion ionomer and by a flexible membrane separating the water from a gas enclosure. Two electrodes are placed one inside the enclosure and the other attached to the engine on the outside. The semi-permeable membrane Nafion allows water motion in and out of the enclosure while blocking anions from being transferred. The two electrodes generate local concentration changes of ions upon the application of an electrical field; these changes lead to osmotic pressures and hence the transfer of water through the semi-permeable membrane. Some aquatic organisms such as pelagic crustacean perform this buoyancy control using an exchange of ions through their tissue to modulate its density relative to the ambient sea water. In this paper, the authors provide an experimental proof of concept of this buoyancy engine. The efficiency of changing the engine's buoyancy is calculated and optimized as a function of electrode surface area. For example electrodes made of a 3mm diameter Ag/AgCl proved to transfer approximately 4mm3 of water consuming 4 Joules of electrical energy. The speed of displacement is optimized as a function of the surface area of the Nafion membrane and its thickness. The 4mm3 displaced volume obtained with the Ag/AgCl electrodes required approximately 380 seconds. The thickness of the Nafion membrane is 180μm and it has an area of 133mm3.

Proceedings Article | 29 March 2011 Paper

Design and development of bio-inspired underwater jellyfish like robot using ionic polymer metal composite (IPMC) actuators

Barbar Akle, Joseph Najem, Donald Leo, John Blottman

Proceedings Volume 7976, 797624 (2011) https://doi.org/10.1117/12.881993

KEYWORDS: Actuators, Electrodes, Polymers, Metals, Ions, Liquids, Gold, Composites, Robotics, Transducers

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Proceedings Article | 23 March 2011 Paper

Modeling and optimization of IPMC actuator for autonomous jellyfish vehicle (AJV)

Keyur Joshi, Barbar Akle, Donald Leo, Shashank Priya

Proceedings Volume 7975, 79750Q (2011) https://doi.org/10.1117/12.881483

KEYWORDS: Actuators, Electrodes, Polymers, Thermal modeling, Finite element methods, Polymeric actuators, Optimization (mathematics), Liquids, Optical simulations, Metals

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Proceedings Article | 31 March 2010 Paper

Finite element modeling of the electromechanical coupling in ionic polymer transducers

Barbar Akle, Wassim Habchi, Thomas Wallmersperger, Donald Leo

Proceedings Volume 7644, 76441U (2010) https://doi.org/10.1117/12.848781

KEYWORDS: Electrodes, Particles, Polymers, Transducers, Finite element methods, Ions, Actuators, Calibration, Numerical simulations, Dielectrics

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Proceedings Article | 6 April 2009 Paper

Forced and free displacement characterization of ionic polymer transducers

Barbar Akle, Andrew Duncan, Etienne Akle, Thomas Wallmersperger, Donald Leo

Proceedings Volume 7287, 72870N (2009) https://doi.org/10.1117/12.815848

KEYWORDS: Transducers, Actuators, Electrodes, Polymers, Temperature metrology, Liquids, Cesium, Lithium, Aluminum, Polymeric actuators

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Ionic polymer transducers (IPT), sometimes referred to as artificial muscles, are known to generate a large bending strain and a moderate stress at low applied voltages (<5V). Recently Akle and Leo[1] reported extensional actuation in ionic polymer transducers. In this study, extensional IPTs are characterized under forced and free displacement boundary condition as a function of transducer architecture. The electrode thickness is varied from 10 μm up to 40 μm while three extensional actuators with Lithium, Cesium, and tetraethylammonium (TEA) mobile cations are characterized. Three fixtures are built in order to characterize the extensional actuation response. The first fixture measures the free displacement of an IPT sample sandwiched between two aluminum plates glued using the electrically conductive silver paste. In the second fixture a spring is compressed against the test sample with variable amounts to generate different levels of pre-stress and prevents the bending of the IPT. In the third fixture dead weights are placed on top of the sample in order to prevent bending. In the spring loaded fixture a thermocouple is placed in the proximity of the actuator and temperature is measured. The different transducers are characterized using a step voltage input and an alternating current (AC) sine wave input. The step input resulted in a logarithmic rise like displacement curve, while the low frequency (<0.1 Hz) AC excitation generated a sine wave displacement response with a strong first harmonic. The high frequency AC excitation generated a response similar to that of the step input. Comparing the measured temperature for step and AC response demonstrated that the sample is heating up when exited with a high frequency signal; which is leading to the expansion of the sample. Initial experimental results demonstrate a strong correlation between electrode architecture and the peak strain response. Strains on the order of 2% are observed with air stable ionic liquid based transducers. A correlation between the strain and charge buildup in the polymer is also characterized. Cesium (Cs) mobile cation outperformed all other tested mobile charges, while Potassium displaced the least. Keywords: Ionic Polymers, Transducer, Actuator, Electroactive Polymer, Extensional Actuator.

Proceedings Article | 6 April 2009 Paper

Electromechanical performance and membrane stability of novel ionic polymer transducers constructed in the presence of ionic liquids

Andrew Duncan, Donald Leo, Timothy Long, Barbar Akle, Jong Park, Robert Moore

Proceedings Volume 7287, 728711 (2009) https://doi.org/10.1117/12.815874

KEYWORDS: Liquids, Polymers, Scattering, Electroactive polymers, Transducers, X-rays, Laser scattering, Glasses, Resistance, Actuators

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Ionic polymer transducers (IPT) are a class of devices that leverage electroactive polymers (EAP), specifically electrolyte-swollen ionomeric membranes, to perform energy conversions. Energy transformation from input to output is referred to as transduction and occurs between the electrical and mechanical domains. The present study expands on IPT investigations with a novel series of sulfonated polysulfones (sBPS), with specific interest in the effect of polymer topology on actuator performance. A hydrophilic ionic liquid was combined with a series of sBPS through a casting method to create hydrated membranes that contained target uptakes (f) of the diluent. The ionic liquid's hydrophilic, yet organic nature raised the issue of its degree of compatibility and miscibility with the microphase separated domains of the host ionomeric membrane. Initial studies of the ionomer - ionic liquid morphology were performed with synchrotron small angle X-ray scattering (SAXS). The effective plasticization of the membranes was identified with dynamic mechanical analysis (DMA) in terms of varied storage modulus and thermal transitions with ionic liquid uptake. Electrical impedance spectroscopy (EIS) was employed to quantify the changes in ionic conductivity for each sBPS ionomer across a range of uptake. Combined results from these techniques implied that the presence of large amounts of ionic liquid swelled the hydrophilic domains of the ionomer and greatly increased the ionic conductivity. Decreases in storage modulus and the glass transition temperature were proportional to one another but of a lesser magnitude than changes in conductivity. The present range of ionic liquid uptake for sBPS was sufficient to identify the critical uptake (f_c) for three of the four ionomers in the series. Future work to construct IPTs with these components will use the critical uptake as a minimum allowable content of ionic liquid to optimize the balance of electrical and mechanical properties for the device components.

Proceedings Article | 30 March 2009 Paper

Improved signal conditioning circuit design for ionic polymer transducers as sensors

Barbar Akle, Nakad Zahi

Proceedings Volume 7292, 72921J (2009) https://doi.org/10.1117/12.815851

KEYWORDS: Sensors, Polymers, Transducers, Electrodes, Signal to noise ratio, Polymeric sensors, Polymer thick film flex circuits, Electroactive polymers, Capacitance, Gold

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Several researchers are actively studying Ionomeric polymer transducers (IPT) as a large strain low voltage Electro- Active Polymer (EAP) actuator. EAPs are devices that do not contain any moving parts leading to a potential large life time. Furthermore, they are light weight and flexible. IPT have the ability to generate bending strains on the order 5% when +2V potential is applied across its thickness. As sensors however, IPTs are proven to be superior compared to any other EAP material when a charge amplifier is used as a signal conditioner. Furthermore, researchers has developed miniature sensors from IPTs that could be flush mounted to a surface and measure shear stresses due to fluid flow at even low Reynolds numbers. Sensor resolution is on the order of 10 mPa enables it to be useful as a wall shear stress sensor for several aero/hydrodynamic and biomedical applications. In this paper a new signal conditioning circuit is designed with superior sensing capabilities compared to the old circuit. In the new circuit the IPT is biased with a small voltage on the order of 5mV to 25 mV. Initial experimental results demonstrated 30% enhancement in signal to noise ratio compared to the old circuit. Furthermore, this circuit enables the use of IPT polymers with larger capacitance compared to the previous circuits. Akle et al. demonstrated that the capacitance of an ionic polymer transducer is proportional to transducer performance. Ionic polymers are generally made of an ion exchange membrane, typically Nafion, coated with a flexible electrode. In this study the Direct Assembly Process (DAP) is used for the fabrication of IPT. The DAP consists of mixing a metal particulate with an ionomer solution and spraying it directly on a diluent saturated ion conducting membrane. The thickness of the electrode is controlled by altering the amount of the ionomer/metal mix sprayed on the membrane. Thicker electrodes provide IPT with a larger capacitance, and hence larger sensitivity is obtained using the new circuit. It was impossible to use the previous signal conditioning circuit for high capacitance sensors. Finally an attempt to model these sensors along with the circuit is provided. By understanding the interaction between the IPT and the signal conditioning circuit we can create devices with even higher sensitivity. The presented circuit will help in modeling and predicting the response of the sensor.

Proceedings Article | 10 April 2008 Paper

Optimization of active electrodes for novel ionomer-based ionic polymer transducers

Andrew Duncan, Stephen Sarles, Donald Leo, Timothy Long, Barbar Akle, Matthew Bennett

Proceedings Volume 6927, 69271Q (2008) https://doi.org/10.1117/12.776575

KEYWORDS: Electrodes, Data modeling, Resistance, Particles, Transducers, Circuit switching, Polymers, Liquids, Interfaces, Electromechanical design

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Proceedings Article | 10 April 2008 Paper

A correlation between extensional displacement and architecture of ionic polymer transducers

Barbar Akle, Andrew Duncan, Donald Leo

Proceedings Volume 6927, 69270J (2008) https://doi.org/10.1117/12.776475

KEYWORDS: Transducers, Actuators, Polymers, Electrodes, Liquids, Polymeric actuators, Data modeling, Gold, Aluminum, Electroactive polymers

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Ionic polymer transducers (IPT), sometimes referred to as artificial muscles, are known to generate a large bending strain and a moderate stress at low applied voltages (<5V). Bending actuators have limited engineering applications due to the low forcing capabilities and the need for complicated external devices to convert the bending action into rotating or linear motion desired in most devices. Recently Akle and Leo reported extensional actuation in ionic polymer transducers. In this study, extensional IPTs are characterized as a function of transducer architecture. In this study 2 actuators are built and there extensional displacement response is characterized. The transducers have similar electrodes while the middle membrane in the first is a Nafion / ionic liquid and an aluminum oxide - ionic liquid in the second. The first transducer is characterized for constant current input, voltage step input, and sweep voltage input. The model prediction is in agreement in both shape and magnitude for the constant current experiment. The values of α and β used are within the range of values reported in Akle and Leo. Both experiments and model demonstrate that there is a preferred direction of applying the potential so that the transducer will exhibit large deformations. In step response the model well predicted the negative potential and the early part of the step in the positive potential and failed to predict the displacement after approximately 180s has elapsed. The model well predicted the sweep response, and the observed 1st harmonic in the displacement further confirmed the existence of a quadratic in the charge response. Finally the aluminum oxide based transducer is characterized for a step response and compared to the Nafion based transducer. The second actuator demonstrated electromechanical extensional response faster than that in the Nafion based transducer. The Aluminum oxide based transducer is expected to provide larger forces and hence larger energy density.

Proceedings Article | 10 April 2008 Paper

Micro deposition method: a novel fabrication method for ionic polymer metallic composites

David Griffiths, Vishnu Baba Sundaresan, Barbar Akle, Pavlos Vlachos, Don Leo

Proceedings Volume 6927, 69270C (2008) https://doi.org/10.1117/12.776462

KEYWORDS: Transducers, Electrodes, Polymers, Head, Actuators, Microfluidics, Composites, Ruthenium, Deposition processes, Fabrication

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Proceedings Article | 2 April 2008 Paper

High surface area electrodes in ionic polymer transducers: numerical and experimental investigations of the chemo-electric behavior

Barbar Akle, Thomas Wallmersperger, Etienne Akle, Donald Leo

Proceedings Volume 6929, 69290N (2008) https://doi.org/10.1117/12.776451

KEYWORDS: Electrodes, Particles, Polymers, Transducers, Computer architecture, Scanning electron microscopy, Finite element methods, Ions, Data modeling, Metals

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Proceedings Article | 18 April 2007 Paper

Development of ionic polymer transducers as flow shear stress sensors: effects of electrode architecture

David Griffiths, Justin Dominic, Barbar Akle, Pavlos Vlachos, Donald Leo

Proceedings Volume 6529, 65290L (2007) https://doi.org/10.1117/12.715841

KEYWORDS: Electrodes, Transducers, Sensors, Capacitance, Polymers, Resistance, Calibration, Amplifiers, Polymeric sensors, Resistors

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Proceedings Article | 5 April 2007 Paper

Development and modeling of novel extensional ionic polymer transducers

Barbar Akle, Thomas Wallmersperger, Donald Leo

Proceedings Volume 6524, 652411 (2007) https://doi.org/10.1117/12.715852

KEYWORDS: Transducers, Electrodes, Actuators, Polymers, Polymeric actuators, Gold, Data modeling, Liquids, Motion models, Ions

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Proceedings Article | 4 April 2007 Paper

Chemo-electric characterization and modeling of the high surface area electrodes in ionic polymer transducers

Thomas Wallmersperger, Barbar Akle, Etienne Akle, Donald Leo

Proceedings Volume 6524, 65240S (2007) https://doi.org/10.1117/12.714011

KEYWORDS: Electrodes, Polymers, Transducers, Particles, Gold, Numerical simulations, Data modeling, Dielectrics, Spherical lenses, Ions

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Proceedings Article | 11 April 2006 Paper

New approaches in the measurement of shear stress and heat flux

Ali Etebari, Jerrod Ewing, Andrew Gifford, Barbar Akle, Thomas Diller, Pavlos Vlachos

Proceedings Volume 6174, 61741W (2006) https://doi.org/10.1117/12.660580

KEYWORDS: Sensors, Heat flux, Calibration, Polymers, Temperature metrology, Polymeric sensors, Transducers, Metals, Skin, Microelectromechanical systems

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Proceedings Article | 6 April 2006 Paper

Investigation on micro-patterned gold-plated polymer substrate for a micro hydraulic actuator

Vishnu Baba Sundaresan, Barbar Akle, Donald Leo

Proceedings Volume 6170, 61701U (2006) https://doi.org/10.1117/12.658613

KEYWORDS: Gold, Actuators, Ions, Resistance, Molecules, Proteins, Polymers, Head, Microfluidics, Polymeric actuators

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Plants have the ability to develop large mechanical force from chemical energy available with bio-fuels. The energy released by the cleavage of a terminal phosphate ion during the hydrolysis of a bio-fuel assists the transport of ions and fluids in cellular homeostasis. Materials that develop pressure and hence strain similar to the response of plants to an external stimuli are classified as nastic materials. This new class of actuators use protein transporters as functional units to move species and result in deformation [Leo et al 2005 (Proceedings of IMECE - 06)]. The ion transporters are hydrocarbons which are formed across the cellular membranes. The membranes that house the ion transporters are aggregates of phospholipids rigidized by cytoskeleton. Reconstituting these nano-machines on a harder matrix is quintessential to build a functional device. Artificial phospholipid membranes or Biliayer lipid membranes (BLM) have poor structural integrity and do not adhere to most surfaces. Patterned arrays of pores made on Poly-propylene glycol-diacrylate (PPG-DA) substrate, a photo curable polymer was made available to us for initial design iterations for an actuator. Hydrophobicity of PPG-DA posed initial problems to support a BLM. We modified the surface of micropatterned PPG-DA membrane by gold plating it. The surface of the porous PPG-DA membranes was plated with gold (Au). A 10nm seeding layer of Au was sputtered on the surface of the membrane. Further gold was reduced onto the sputtered gold surface [Supriya et al(Langmuir 2004, 20, 8870-8876)] by suspending the samples in a solution of hydroxylamine and Hydrogen tetrachloroaurate(III) trihydrate [HAuCl4.3H2O]. This reduction process increased the thickness of the gold, enhanced its adhesion to the PPG-DA substrate and improved the shapes of the pores. This surface modification of PPG-DA helped us form stable BLM with 1-Palmitoyl-2-Oleoyl-sn-Glycero-3- [Phospho-L-Serine] (Sodium Salt) (POPS), 1-Palmitoyl-2-Oleoyl-sn-Glycero- 3-Phosphoethanolamine (POPE) lipids. The observed ionic resistance of the BLM remained stable and sustained 4 mm water column for the the four hours observation period. This article describes the procedure we adopted to modify the PPG-DA substrate, form a BLM and the procedure to quantify the stability of the BLM formed with -amine and -thiol head groups in the lipids.

Proceedings Article | 15 March 2006 Paper

Reliability of high-strain ionomeric polymer transducers fabricated using the novel direct assembly process

Barbar Akle, Saila Nawshin, Donald Leo

Proceedings Volume 6168, 61680P (2006) https://doi.org/10.1117/12.658907

KEYWORDS: Transducers, Polymers, Electrodes, Reliability, Gold, Liquids, Scanning electron microscopy, Actuators, Humidity, Polymeric actuators

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Ionomeric polymer transducers have received considerable attention in the past several years. These actuators, sometimes referred to as artificial muscles, have the ability to generate large bending strain and moderate stress at low applied voltages. Typically, ionic polymer actuators are composed of Nafion-117 membranes with platinum electrodes and are saturated with water diluents. Recently the authors have developed a novel fabrication technique named the Direct Assembly Process (DAP), which allowed good control on electrode morphology and composition. The DAP consists of spraying two high surface area metal-ionomer electrodes on a Nafion membrane. A single- walled carbon nanotubes (SWNT) and ruthenium dioxide (RuO₂) hybrid electrode was sprayed on a Formamide hydrated Nafion-117 membrane using the DAP method. This transducer was shown to generate 9.4% peak-peak strain under the application of ±2V at a strain rate of 1%/sec. Furthermore using the DAP one is capable of incorporating several types of diluents in ionomeric polymer transducers. Transducers with ionic liquid diluents are demonstrated to operate in air for long periods of time. In this work we will present a reliability study of transducers fabricated using the DAP. Each transducer is tested under a frequency range of 0.2Hz to 1Hz, and a potential of ±1V to ±3V. Water hydrated transducers dehydrates and stop moving within 5 minutes while operating in air under ±2V. Transducers with Formamide diluents operate for 20,000 cycles under ±1.5V and 0.5Hz (around 11hrs), while they degrade in less than 3000 cycles under ±2V and 0.5Hz. Ionic liquid based transducers are demonstrated to operate in air for over 400,000 with little loss in performance, and over 1 million cycle with a loss of only 43%. Actuators with several electrode compositions are fabricated and a correlation between the reliability of ionic liquid-ionic polymer transducers and maximum strain will be presented. This correlation will be used to assess the adhesion between the high surface area electrodes and the Nafion membrane. SEM images of tested transducers will be presented.

Proceedings Article | 6 May 2005 Paper

Ionic electroactive hybrid transducers

Barbar Akle, Matthew Bennett, Donald Leo

Proceedings Volume 5759, (2005) https://doi.org/10.1117/12.599983

KEYWORDS: Single walled carbon nanotubes, Transducers, Electrodes, Actuators, Polymers, Liquids, Carbon nanotubes, Metals, Capacitance, Gold

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Ionic electroactive actuators have received considerable attention in the past ten years. Ionic electroactive polymers, sometimes referred to as artificial muscles, have the ability to generate large bending strain and moderate stress at low applied voltages. Typical types of ionic electroactive polymer transducers include ionic polymers, conducting polymers, and carbon nanotubes. Preliminary research combining multiple types of materials proved to enhance certain transduction properties such as speed of response, maximum strain, or quasi-static actuation. Recently it was demonstrated that ionomer-ionic liquid transducers can operate in air for long periods of time (>250,000 cycles) and showed potential to reduce or eliminate the back-relaxation issue associated with ionomeric polymers. In addition, ionic liquids have higher electrical stability window than those operated with water as the solvent thereby increasing the maximum strain that the actuator can produce. In this work, a new technique developed for plating metal particulates on the surface of ionomeric materials is applied to the development of hybrid transducers that incorporate carbon nanotubes and conducting polymers as electrode materials. The new plating technique, named the direct assembly process, consists of mixing a conducting powder with an ionomer solution. This technique has demonstrated improved response time and strain output as compared to previous methods. Furthermore, the direct assembly process is less costly to implement than traditional impregnation-reduction methods due to less dependence on reducing agents, it requires less time, and is easier to implement than other processes. Electrodes applied using this new technique of mixing RuO₂ (surface area 45~65m²/g) particles and Nafion dispersion provided 5x the displacement and 10x the force compared to a transducer made with conventional methods. Furthermore, the study illustrated that the response speed of the transducer is optimized by varying the vol% of metal in the electrode. For RuO₂, the optimal loading was approximately 45%. This study shows that carbon nanotubes electrodes have an optimal performance at loadings around 30 vol%, while PANI electrodes are optimized at 95 vol%. Due to low percolation threshold, carbon nanotubes actuators perform better at lower loading than other conducting powders. The addition of nanotubes to the electrode tends to increase both the strain rate and the maximum strain of the hybrid actuator. SWNT/RuO₂ hybrid transducer has a strain rate of 2.5%/sec, and a maximum attainable peak-to-peak strain of 9.38% (+/- 2V). SWNT/PANI hybrid also increased both strain and strain rate but not as significant as with RuO₂. PANI/RuO₂ actuator had an overwhelming back relaxation.

Proceedings Article | 27 July 2004 Paper

Effects of electrode morphology on the performance of BPSH and PATS ionic polymer transducers

Barbar Akle, Kenton Wiles, Donald Leo, James McGrath

Proceedings Volume 5385, (2004) https://doi.org/10.1117/12.539528

KEYWORDS: Polymers, Transducers, Electrodes, Platinum, Metals, Acquisition tracking and pointing, Capacitance, Scanning electron microscopy, Plating, Actuators

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Proceedings Article | 28 July 2003 Paper

Multilayer ionic polymer transducer

Barbar Akle, Donald Leo

Proceedings Volume 5051, (2003) https://doi.org/10.1117/12.484400

KEYWORDS: Polymers, Transducers, Actuators, Sensors, Multilayers, Mathematical modeling, Polymeric actuators, Resistance, Packaging, Polymeric sensors

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Showing 5 of 27 publications

Proceedings Volume Editor (1)

SPIE Conference Volume | 30 April 2014

Electroactive Polymer Actuators and Devices (EAPAD) 2014

Conference Committee Involvement (17)

Electroactive Polymer Actuators, Sensors, and Devices (EAPAD) 2025

17 March 2025 | Vancouver, B.C., Canada

Electroactive Polymer Actuators and Devices (EAPAD) XXVI

25 March 2024 | Long Beach, California, United States

Electroactive Polymer Actuators and Devices (EAPAD) XXV

13 March 2023 | Long Beach, California, United States

Electroactive Polymer Actuators and Devices (EAPAD) XXIV

7 March 2022 | Long Beach, California, United States

Electroactive Polymer Actuators and Devices (EAPAD) XXIII

8 March 2021 | Online Only, California, United States

Electroactive Polymer Actuators and Devices (EAPAD) XXII

27 April 2020 | Online Only, California, United States

Electroactive Polymer Actuators and Devices (EAPAD) XXI

4 March 2019 | Denver, Colorado, United States

Electroactive Polymer Actuators and Devices (EAPAD) XX

5 March 2018 | Denver, Colorado, United States

Electroactive Polymer Actuators and Devices (EAPAD) XIX

26 March 2017 | Portland, Oregon, United States

Electroactive Polymer Actuators and Devices (EAPAD) XVIII

21 March 2016 | Las Vegas, Nevada, United States

Electroactive Polymer Actuators and Devices (EAPAD) XVII

9 March 2015 | San Diego, California, United States

Electroactive Polymer Actuators and Devices (EAPAD) XVI

10 March 2014 | San Diego, California, United States

Electroactive Polymer Actuators and Devices (EAPAD) XV

11 March 2013 | San Diego, California, United States

Electroactive Polymer Actuators and Devices (EAPAD) XIV

12 March 2012 | San Diego, California, United States

Electroactive Polymer Actuators and Devices (EAPAD) XIII

7 March 2011 | San Diego, California, United States

Electroactive Polymer Actuators and Devices (EAPAD) XII

8 March 2010 | San Diego, California, United States

Electroactive Polymer Actuators and Devices (EAPAD) XI

9 March 2009 | San Diego, California, United States

Showing 5 of 17 Conference Committees

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