Dissertations / Theses on the topic 'Ionic Polymer Metal Composites (IPMC)'

Ionic Polymer Metal Composite (IPMC) is a class of electroactive polymer , that is receiving great attention due to its advantages of large bending deflection, low power consumption and driving voltage. Although there is still no commercial application of IPMC, it has been actively investigated by researchers for the past decade. The IPMC has been identified as a potential material to be used in the specific application of sensor and/or actuation, such as microgripper and micropump. This research deals with the characterisation of small scale IPMC with the ultimate objective to develop a simple microgripper to demonstrate the ability of the IPMC to grasp a micro object. A vision system has been developed to perform image processing to measure the displacement of IPMC. New algorithms of edge detection and displacement measurement have been introduced to characterise the IPMC. Comparison between laser sensor measurements and vision systems measurement has been carried out and the results showed that the vision system is a reliable measurement. Characterisation of small scale IPMC is carried out to prove the claim that miniaturization of IPMC is possible without degrading its performance. The characterisation of the IPMC actuator is divided into two major works - the displacement and blocked force measurements. The results showed that small scale characteristics are in line with the results that have been published by other researchers for larger scale of IPMC, hence supported the claim. The dynamic sensory behaviour of the IPMC has also been characterised. The results showed that the sensor functions are better in terms of producing consistent output signals when it is dehydrated. With such finding, the possibility of using the IPMC as the actuator and sensor at the same time for micro gripper application is not promising because the actuator needs to be fully hydrated in order to work better while the sensor is working better in a dehydrated condition. The final part in this research work is to develop a simple micro gripper. A two-finger microgripper with size of lOmm x 2rnrn x O.2mm is controlled by a vision feedback system to grasp small objects. For a demonstration purposes, an object with diameter of lmm was successfully grasped in 4.6 seconds.

This thesis describes the open-loop behavior of an ionic polymer metal composite (IPMC) strip as a novel actuator, the empirical force and position models, the control system and the improved dynamic characteristics with the feedback control implemented. Ionic polymer metal composite is a novel polymer in the class of electroactive polymers. IPMC consists of a base polymer coated with electrodes made up of highly conducting pure metals such as gold. The actuation behavior of IPMC can be attributed to the bending of an IPMC strip upon application of voltage across its thickness. The main reasons for the bending are ion migration on the application of voltage and swelling and contraction caused by water content. An experimental setup to study the open-loop force and tip displacement of an IPMC strip in a cantilever configuration was developed, and real time controllers were implemented. In open loop, the force response of the IPMC strip of dimensions 25 mm x 3.9 mm x 0.16 mm to a 1.2-V step input is studied. The open-loop rise time was 0.08 s and the percent overshoot was 131.62 %, while the settling time was about 10 s. Based on this open-loop step response using a least-square curve-fitting methodology, a fourth-order empirical transfer function from the voltage input to the force output was derived. The tip displacement response of an IPMC strip of dimensions 23 mm x 3.96 mm x 0.16 mm to a 1.2-V step input was also studied. The step response exhibited a 205.34 % overshoot with a rise time of 0.08 s, and the settling time was 27 s. A fourth-order empirical transfer function from the step input to the tip displacement as output was also derived. Based on the derived transfer functions lead-lag feedback controllers were designed for precision control of both force and displacement. The control objectives were to decrease the settling time and the percent overshoot, and achieve reference input tracking. After implementing the controllers, the percent overshoot decreased to 30% while the settling time was reduced to 1.5 s in case of force control. With position control, the settling time was reduced to 1 s while the percent overshoot decreased to 20%. Precision micro-scale force and position-control capabilities of the IPMC were also demonstrated. A 4 ?N force resolution was achieved, with a force noise of 0.904-?N rms. The position resolution was 20 ?m with a position noise of 7.6-?m rms.

This thesis presents the design and development of a novel biomimetic jellyfish robot that features ionic polymer metal composite actuators. The shape and swimming style of this underwater vehicle are based on oblate jellyfish species, which are known for their high locomotive efficiency. Ionic polymer metal composites (IPMC) are used as actuators in order to contract the bell and thus propel the jellyfish robot. This research focuses on translating the evolutionary successes of the natural species into a jellyfish robot that mimics the geometry, the swimming style, and the bell deformation cycle of the natural species. Key advantages of using IPMC actuators over other forms of smart material include their ability to exhibit high strain response due to a low voltage input and their ability to act as artificial muscles in water environment. This research specifically seeks to implement IPMC actuators in a biomimetic design and overcome two main limitations of these actuators: slow response rate and the material low blocking force. The approach presented in this document is based on a combination of two main methods, first by optimizing the performance of the IPMC actuators and second by optimizing the design to fit the properties of the actuators by studying various oblate species. Ionic polymer metal composites consist of a semi-permeable membrane bounded by two conductive, high surface area electrode. The IPMCs are manufactured is several variations using the Direct Assembly Process (DAP), where the electrode architecture is controlled to optimize the strain and stiffness of the actuators. The resulting optimized actuators demonstrate peak to peak strains of 0.8 % in air and 0.7 % in water across a frequency range of 0.1-1.0 Hz and voltage amplitude of 2 V. A study of different oblate species is conducted in order to attain a model system that best fits the properties of the IPMC actuators. The Aequorea victoria is chosen based on its bell morphology and kinematic properties that match the mechanical properties of the IPMC actuators. This medusa is characterized by it low swimming frequency, small bell deformation during the contraction phase, and high Froude efficiency. The bell morphology and kinematics of the Aequorea victoria are studied through the computation of the radius of curvature and thus the strain energy stored in the during the contraction phase. The results demonstrate that the Aequorea victoria stores lower strain energy compared to the other candidate species during the contraction phase. Three consecutive jellyfish robots have been built for this research project. The first generation served as a proof of concept and swam vertically at a speed of 2.2 mm/s and consumed 3.2 W of power. The second generation mimicked the geometry and swimming style of the Aurelia aurita. By tailoring the applied voltage waveform and the flexibility of the bell, the robot swam at an average speed of 1.5 mm/s and consumed 3.5 W of power. The third and final generation mimicked the morphology, swimming behavior, and bell kinematics of the Aequorea victoria. The resulting robot, swam at an average speed of 0.77 mm/s and consumed 0.7 W of power when four actuators are used while it achieved 1.5 mm/s and 1.1 W of power consumption when eight actuators are used. Key parameter including the type of the waveform, the geometry of the bell, and position and size of the IPMC actuators are identified. These parameters can be hit later in order to further optimize the design of an IPMC based jellyfish robot.
Master of Science

An ionic polymer actuator consists of a thin Nafion-117 sheet plated with gold or platinum on both sides. An ionic polymer actuator undergoes large deformation in the presence of low applied voltage across its thickness and exhibits low impedance. They can also be used as large displacement sensors by bending them to induce stresses and generate a voltage response. They operate best in a humid environment. Ionic polymer actuators have been used for various practical applications such as bio-mimetic robotic propulsion, flexible low mass robotic arms, propellors for swimming robotic structures, linear and platform type robotic actuators and active catheter systems. One of the disadvantages of ionic polymer actuators is that their settling time to a unit step voltage is on the order of 5-20 seconds in a cantilever configuration. The slow time constant of an ionic polymer limits the actuation bandwidth. The characteristics of ionic polymer actuators, low force and large displacement (as compared to other actuator technologies such as PZT or PVDF), cannot be used in applications requiring a faster response time for a given actuation signal. Due to this limitation, many applications will not be able to make use of the large displacement effectively because of the limited bandwidth of the actuator. Another disadvantage of using an ionic polymer actuator is that the stiffness of the actuator is a function of the hydration of the polymer. Difficulties in controlling the hydration, which changes with respect to time, results in inconsistencies in the mechanical response exhibited by the polymers during continual usage. Several physical models of ionic polymer actuators have been proposed. The physical phenomenon responsible for the bending is not completely understood and no clear set of principles have been able to explain the motion of the polymers completely. Physical phenomena like ionic motion, back diffusion of water and electrostatic force have been used to explain these models. This research demonstrates the use of feedback control to overcome the limitation of slow settling time. First, an empirical model of the ionic polymers developed by Kanno was modified by studying the step response of these actuators. The empirical model is used to design a feedback compensator by state space modeling techniques. Since the ionic polymer actuator has a slow settling time in the open-loop, the design objectives are to minimize the settling time and constrain the control voltage to be less than a prescribed value. The controller is designed using Linear Quadratic Regulator (LQR) techniques which reduced the number of design parameters to one variable. Simulations are performed which show settling times of 0.03 seconds for closed-loop feedback control are possible as compared to the open-loop settling time of 16-18 seconds. The maximum control voltage varied from 1.2 Volts to 3.5 Volts depending on the LQR design parameter. The controller is implemented and results obtained are consistent with the simulations. Closed-loop settling time is observed to be 4-8 seconds and the ratio of the peak response to the steady-state response is reduced by an order of magnitude. Discrepancies between the experiment and the simulations are attributed to the inconsistencies in the resonant frequency of the actuator. Experiments demonstrate that changes in the surface hydration of the polymer result in 20\% variations in the actuator resonance. Variations in the actuator resonance require a more conservative compensator design, thus limiting the performance of the feedback control system.
Master of Science

This thesis describes the use of an ultrasonic goal-seeking algorithm while using ionic polymer metal composite (IPMC), an electroactive polymer, as the actuator to drive a vessel towards a goal. The signal transmitting and receiving circuits as well as the goal seeking algorithm are described in detail. Two test vessels were created; one was a larger vessel that contained all necessary components for autonomy. The second was a smaller vessel that contained only the sensors and IPMC strips, and all power and signals were transmitted via an umbilical cord. To increase the propulsive efforts of the second, smaller vessel, fins were added to the IPMC strips, increasing the surface area over 700%, determined to yield a 22-fold force increase. After extensive testing, it was found that the three IPMC strips, used as oscillating fins, could not generate enough propulsion to move either vessel, with or without fins. With the addition of fins, the oscillating frequency was reduced from 0.86-Hz to 0.25-Hz. However, the goal-seeking algorithm was successful in guiding the vessel towards the target, an ultrasonic transmitter. When moved manually according to the instructions given by the algorithm, the vessel successfully reached the goal. Using assumptions based on prior experiments regarding the speed of an IPMC propelled vessel, the trial in which the goal was to the left of the axis required 18.2% more time to arrive at the goal than the trial in which the goal was to the right. This significant difference is due to the goal-seeking algorithm’s means to acquire the strongest signal. After the research had concluded and the propulsors failed to yield desired results, many factors were considered to rationalize the observations. The operating frequency was reduced, and it was found that, by the impulse-momentum theorem, that the propulsive force was reduced proportionally. The literature surveyed addressed undulatory motion, which produces constant propulsive force, not oscillatory, which yields intermittent propulsive force. These reasons among others were produced to rationalize the results and prove the cause of negative results was inherent to the actuators themselves. All rational options have been considered to yield positive results.

This thesis presents work done to improve the switching speed and contrast performance of electrochromic devices. Layer-by-Layer (LbL) assembly was used to deposit thin electrochromic films of materials ranging from organic, inorganic, conducting polymers, etc. The focus was on developing new materials with high contrast and long lifecycles. A detailed switching-speed study of solid-state EC devices of already-developed (PEDOT (Poly(3,4-ethylenedioxythiophene)), polyviologen, inorganic) materials and some new materials (Prodot-Sultone) was performed. Work was done to achieve the optimum thickness and number of bilayers in LbL films resulting in high-contrast and fast switching. Device sizes were varied for comparison of the performance of the lab-made prototype device with the commercially available â small pixelâ size displays. Symmetrical EC devices were fabricated and tested whenever conducting polymers are used as an EC material. This symmetrical configuration utilizes conducting polymers as an electroactive layer on each of two ITO-coated substrates; potential is applied to the two layers of similar conducting polymers and the device changes color from one redox state to another. This method, along with LbL film assembly, are the main factors in the improvement of switching speed results over already-published work in the literature. PEDOT results show that EC devices fabricated by LbL assembly with a switching speed of less than 30 ms make EC flat-panel displays possible by adjusting film thickness, device size, and type of material. The high contrast value (84%) for RuP suggests that its LbL films can be used for low-power consumption displays where contrast, not fastest switching, is the prime importance. In addition to the electrochromic work, this thesis also includes a section on the application of LbL assembly in fabricating electromechanical bending actuators. For bending actuators based on ionic polymer metal composites (IPMCs), a new class of conductive composite network (CNC) electrode was investigated, based on LbL self-assembled multilayers of conductive gold (Au) nanoparticles. The CNC of an electromechanical actuator fabricated with 100 bilayers of polyallylamine hydrochloride (PAH)/Au NPs exhibits high strain value of 6.8% with an actuation speed of 0.18 seconds for a 26 µm thick IPMC with 0.4 µm thick LbL CNCs under 4 volts.
Ph. D.

The overall goal of this investigation was to elucidate specific structure-property relationships in perfluorosulfonate ionomers (PFSIs)-related materials. The project can be broken into two primary foci. First, we explored the current state of understanding related to morphology-property relationships in PFSIs with specific attention to the nano-scale organization of the ionic and crystalline domains. Specifically, the effect of uniaxial orientation on the structure and transport properties of Nafion® membranes was examined. Small angle X-ray scattering (SAXS) experiments on dry membranes that were uniaxially elongated showed a strong anisotropic morphology which was shown to persist over the swelling process without a significant relaxation. Hermanâ s order parameters for the ionomer peak were strongly influenced by uniaxial deformation, which supports the presence of cylindrical rather than spherical morphology for ionic domains. Comparison of the water diffusion coefficients between unoriented and oriented samples revealed that uniaxial deformation of Nafion® membranes essentially enhances transport ability in one direction (i.e., the parallel to draw direction) and suppresses in the other two directions (i.e., two orthogonal directions relative to the stretching direction). Based on 1-dimensional analyses of oriented SAXS patterns at the azimuthal angle 90o, three recent models (lamellar model, semicrystalline rod-like model and fringed-micelle model) for the morphology of PFSIs were critically evaluated. The loss of meridional scattering, different orientation behavior of the crystalline and ionic domains, and inherent chain stiffness precludes the possibility of a chain-folded lamellar morphology. While the inter-aggregate dimensions remain constant at high draw ratios, the inter-crystalline spacings decrease significantly. Coupled with the distinctly different orientation behavior, these observations preclude the existence of crystallites solely within rod-like aggregates. While the worm-like ionic channel model was able to explain the behavior of SAXS and wide angle X-ray scattering (WAXS) relatively well, this model also had limitations such as (1) crystalline domains directly linked to the ionic domain (and thus a lack of amorphous domains) and (2) a presence of only a single ionic channel between two neighboring crystallites. Second, electroactive materials, specifically ionic polymer-metal composites (IPMCs) that undergo bending motions with the stimulus of a relatively weak electric field were fabricated. To understand the role of the nanoscale morphology of the membrane matrix in affecting the actuation behavior of IPMC systems, we evaluated actuation performance of IPMCs subjected to uniaxial orientation. The PFSI nanostructure altered by uniaxial orientation mimicked the fibrillar structure of biological muscle tissue and yielded a new anisotropic actuation response. It was evident that IPMCs cut from films oriented perpendicular to the draw direction yielded displacement values that were significantly greater than that of unoriented IPMCs. In contrast, IPMCs cut from films oriented parallel to the draw direction appeared to resist bending and yield displacement values that were much less than that of the unoriented IPMC. This anisotropic actuation behavior was attributed to the contribution of the nanoscale morphology to the bulk bending modulus. Overall, this study clearly demonstrated, for the first time, the importance of the nanoscale morphology in affecting/controlling the actuation behavior in IPMC systems.
Ph. D.

Ionomeric polymer transducers (IPTs) are an exciting new class of smart materials that can serve a dual purpose in engineering or biomedical applications as sensors or actuators. Most commonly they are used for mechanical actuation, as they have the ability to generate large bending strains and moderate stress under low applied voltages. Although the actuation capabilities of IPTs have been extensively studied, the sensing capabilities of these transducers have yet to be fully explored. The work presented herein aims to investigate the fundamental sensing characteristics of these transducers and apply the acquired knowledge toward the development of an electronic stethoscope for digital auscultation. The sensors were characterized both geometrically and electrically to determine their effectiveness in resolving a signal from sub 1 Hz to 2 kHz. Impedance spectroscopy was used to interrogate the sensing mechanism. Following the characterization of the transducer, a bioâ acoustic sensor was designed and fabricated. The bioâ acoustic sensor was placed over the carotid artery to resolve the arterial pressure waveform in situ and on the thorax to measure the S1 and S2 sounds generated by the heart. The temporal response and spectral content was compared with previously known data and a commercially available electronic stethoscope to prove the acquisition of cardiovascular sounds.
Master of Science

Ionic polymer-metal composites (IPMCs) are widely studied for their potential as electromechanical sensors and actuators. Bending of the IMPC depends on internal ion motion under an electric potential, and the addition of an ionic liquid and ionic self-assembled multilayer (ISAM) conductive network composite (CNC) strongly enhances bending and improves lifetime. Ion conducting polyelectrolytes poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS) and Nafion® were incorporated into an ISAM CNC film with poly(allylamine hydrochloride) (PAH) and anionic gold nanoparticles actuators to further improve bending. CNC films were optimized for bending through pH adjustments in PAH and adding NaCl to the PAMPS and Nafion® solutions. PAMPS-containing actuators showed larger and faster bending than those containing Nafion® in the CNC. The IPMC actuator was also evaluated for its potential as a humidity sensor based on its relative humidity (RH) dependent steady-state current. The detection range is at least 10-80%RH, with 5%RH increment differentiation and likely better resolution. Effects of CNC presence and thickness were studied, in conjunction with ionic liquid at a range of RH values. A thin CNC (pH 4 PAH) produced the greatest current differentiation between RH values. The current's response speed to a large RH decrease was approximately 4 times faster than that of a fast commercial digital hygrometer. Additionally, the presence of a CNC and ionic liquid improved the current response time. These results indicate that an IPMC based humidity sensor using a CNC and ionic liquid is very promising and merits further study.
Master of Science

This thesis focuses on the use of smart materials in microrobotic applications. The development of materials with the capabilities to mechanically respond to electrical stimuli or, at the same time, to electrically respond to mechanical stimuli, has entailed the microrobotics rapid evolution. Along this thesis the use of three smart materials families in the filed of microrobotics is studied. The materials used are the piezoelectric ceramics, the piezoelectric polymers and the ionic polymers metal composites IPMC. The similitude in the way they respond to external stimuli has motivated this study. The three materials respond with an induced mechanical strain under the application of an electric field and respond with an induced electrical charge variation when a mechanical pressure is applied. Although these materials respond similarly, their application in microrobotic systems entails different problems. In this thesis their use in different applications is studied and the problems enclosed with their use are treated.
First of all in this thesis the use of piezoelectric polymers and ionic polymers as materials for motion control of microrobots is studied. Their flexibility opens the door to new applications for microrobot systems as is the case of biomimetics. The first application regards the use of piezoelectric polymers in insect-like mm3 microrobot. The microrobot is composed with three legs and one antenna or tool for object collision based on piezoelectric polymers. The object collision tool is used as a sensor for motion control to avoid collisions with other objects. The work presented consists on the development of theoretical models to predict the motion of he leg and the tool of the microrobot. The second application regards the development of a control system for controlling the motion of an ionic polymer IPMC underwater. It is difficult to obtain physical models that describe the motion of these materials, thus it is important to design control strategy to work with IPMCs. Furthermore in this thesis, the problem of manufacturing electrodes for IPMC is also treated.
In the second part of the thesis the use of piezoelectric ceramics to harvest power from mechanical vibrations is studied. Piezoelectric ceramics have higher energy densities compared with other methods for power harvesting from vibrations. In comparison with the piezoelectric polymers, the piezoelectric ceramics produce voltages and current levels more acceptable. From the study performed in this thesis the conditions for a maximum power generation are obtained and an optimum electronic circuit for energy storage and management is designed. At the end of the thesis the capabilities to harvest power using ionic polymers are studied.

KEY WORDS: Smart Materials, Microrobotic, Harvesting, Motion Control, Fonic Polimer, FPMC Piezoelectric, Modelling
Aquesta tesis es centra en l'ús de materials "smart" o intel·ligents en aplicacions de microrobòtica. Al llarg de la tesi treballem amb tres famílies de materials "smart" diferents: les ceràmiques piezoelèctriques, els polímers piezoelèctrics i els polímers iònics coneguts com Ionic Polymer Metal Composites (IPMC). Aquests materials tenen en comú que al aplica'ls-hi un camp elèctric pateixen una deformació mecànica mentre que si els sotmetem a una deformació mecànica, aquests materials pateixen una variació en la seva càrrega elèctrica interna. Degut a aquestes propietats aquests materials poden ser utilitzats com a sensors o com a actuadors.
A la primera part de la tesi estudiem l'ús dels polímers piezoelèctrics i dels polímers iònics per al control del moviment dels microrobots. La primera aplicació que es presenta tracta d'un microrobot de dimensions mm3 que utilitza els polímers piezoelèctrics com a potes i com a sensors de col·lisió. Tot seguit presentem una aplicació a on els IPMCs són utilitzats com a microposicionadors treballant sota de l'aigua.
A la segona part de la tesis estudiem la viabilitat d'utilitzar les ceràmiques piezoelèctriques i els polímers iònics per a generar energia a partir de vibracions mecàniques residuals ambientals. L'estudi presentat determina els nivells de potència generats i les condicions òptimes per a la generació de la màxima potencia.

Ionic electro-active polymers (IEAPs) constitute a promising solution for developing self-regulating, flexible and adaptive mechanical actuators in the area of soft robotics, micromanipulation and rehabilitation. These smart materials have the ability to undergo large bending deformations as a function of a low applied voltage (1 to 5 V), as a result of the ions migration through their inner structure when the network is liquid filled. Among this broad family of materials, ionic-polymer-metal composites (IPMC) based on DuPont’s Nafion® have attracted an increasing interest for the production of light weight controllable soft machines due to their easiness to be metalized (e.g. by mean of electroless plating), fast response and capability of working exposed to air. However, the high cost of the material, its relatively low working density (i.e. the maximum mechanical work output per unit volume of active material that drives the actuation) and weak force output, as well as the considerable fatigue effects endured by the surface electrodes upon cycling, is limiting the performance of these IPMC actuators and hindering their implementation in traditional mechatronic and robotic systems. On the other hand, ionic hydrogels, such as poly(acrylic acid) (PAA) and poly-styrene sulfonate (PSS) based polymers, exhibit controllable mechanical properties and porosity and have shown to be excellent candidates to be used as electrically triggered artificial muscles and miniaturized robots operating in aqueous environments. Although the relatively low cost of these materials render them appealing for mass production scale up, the applicability of these polymeric actuators is limited to a liquid environment, which is intrinsically facilitating the solvent evaporation when the hydrogels are exposed to air. Furthermore, because of the difficulty encountered in fabricating stable and anchored metal structures on these polymer surfaces, these smart soft systems operate in a non-contact configuration with respect to the pilot electrodes, therefore increasing the actuators response time up to few tenths of seconds. In order to achieve an efficient electromechanical transduction along with a stable and durable performance for electro-active actuators operating in air, two main interplaying characteristics must be tailored when designing the system. On one hand side, the need of electrodes that are physically interpenetrating with the polymeric basis is of absolute priority, since the intercalation of ions into the electrode layers and the resulting material volumetric change are fundamental for strain generation. On the other hand, the formulation and engineering of new low cost materials able to merge highly elastic properties and efficient ionic transport features is of crucial importance. The present thesis work deals with the formulation, synthesis and manufacturing of a novel ionic gel/metal nanocomposite (IGMN) that was designed and developed to merge the advantageous properties of both IPMCs and ionic hydrogel actuators and to contextually overcome many of the above mentioned drawbacks characteristic of these two families of polymers. These composites were obtained by mean of Supersonic Cluster Beam Implantation (SCBI). This technique, developed in-house, relies on the use of supersonically accelerated gas-phase metal cluster beams directed onto a polymeric substrate in order to generate thin conductive layers (few tenths to few hundreds of nanometers thick) anchored to the polymer. This scalable approach already proved to be suitable for the manufacturing of elastomer/metal functional nanocomposites, and, as described in this work, it enabled the production of cluster-assembled gold electrodes (100 nm thick) interpenetrating with an engineered ionic gel matrix. This novel approach led to the fabrication of highly conductive metal nanostructures, large surface area for ions storage and providing minimal interfacial stresses between the metal layer and the polymeric basis upon deformation. The key features of this novel system comprise the control on the polymer elasticity, bending actuation in air from 0.1V to 5V, fast response time (< 300 ms), high displacement (> 5 cm), high work density ( >10 J/cm3), minimal electrodes fatigue upon cycling and low manufacturing costs. A bottom-up approach was firstly adopted to engineer and produce Uv photo-cross-linked ionic co-polymers (iongel) with tailored mechanical properties and provided with inorganic nano-structures embedded in the macromolecular matrix which show excellent long-term performance. The polymer is based on poly(acrylic acid)-co-poly(acrylonitrile) (PAA-co-PAN) co-polymers, which are chemically cross-linked in a hydrogel-like fashion and swollen with suitable imidazolium-based ionic liquid. The materials are produced as 100 um freestanding layers using a one-pot synthesis and a simple molding process. Due to the incommensurably low vapor pressure of the ionic liquid, issues concerning the shrinkage of traditional water swollen gels operating exposed to air could be avoided. An organic cation (tetraethyl ammonium, TEA+) is stably coordinated to the carboxyl groups of the PAA and free to move in the polymer sieve-like structure when a small voltage is applied at the electrodes. PAN was introduced to enhance the elastic properties of whole polymer. In the bulk polymer, halloysite nanoclays (HNC) are physically embedded into the gel in order to both improve the toughness of the gel and to improve the ionic conductivity of the system. In fact, the nanostructures interacts with the imidazolium cation of the ionic liquid through an oxygen reduction reaction, and therefore the latter is able to contribute to the charge transport phenomena induced by the electric field due to the solvent partial dissociation. Furthermore, the porosity of the polymer, tailored by the cross-linker, creates physical channels to favor the mobility of positive ions when an electric field is applied. The contribution of both the positive charged species (TEA+ and cations of ionic liquid) that accumulates at the nanostructured electrode in a double layer capacitance regime generates a differential swelling at the opposite sides of the actuator, which bends towards the anode. As it will be shown in the next sections, the actuation mechanism of the IGMN could be modeled according to both the material structure and design, as well as to the experimental data on its electrochemical and electro-mechanical properties.Comparing with traditional soft polymers incompatibility with current metallization processes, like electroless plating or surface silver laminated electrodes fabrication, which are not suitable to guarantee long-term actuation of the components, SCBI demonstrated to be a suitable technique for the production of next generation electro-active soft actuators. The IGMN-based actuators showed superior performance, such as large bending displacement, fast response time, long durability in a low voltage regime during the actuation process. The combination of the SCBI fabrication technology with the ionic gel synthesis and fabrication renders the manufacturing of these systems time-saving and costs-effective, and the unique properties of these actuators render them good candidates for potential scale up and for applications in micro-electromechanical systems, microfluidics, soft robotics, and rehabilitation.

碩士
中原大學
醫學工程研究所
97
Ionic polymer-metal composites (IPMC) are a kind of electroactive polymer (EAP) that has been used for various applications, such as artificial muscles, sensors and actuators, because of its light weight and ability to make more than 100% bending deformation under low driving voltage. In this study, an IPMC actuator was incorporated into a self-designed device for application as an implantable drug delivery system. First, IPMC films with different thickness, dimensions and metal electrodes were constructed. The second step required a basic measurement of the IPMC actuation performance, including displacement and output force. A third step utilized a closed-loop PID controller to solve the unrepeatable characteristics of an IPMC in the open-loop position response. Finally, an IPMC actuator was incorporated into a design of a drug delivery device and its drug delivery performance consequently studied. A variety of IPCM films having different thickness (200、100 and 50 μm)、dimensions (3×1、3×0.5 cm2) and metal materials (Au and Pt) were successfully fabricated. A difference in surface morphology was observed by SEM between gold and platinum electrodes. The actuation performance results showed that the gold electrode was better then platinum electrode of IPMC. Furthermore, as the thickness of the IPMC film increased, the bending displacement decreased but the output force result is opposite to the displacement because the stiffness of IPMC film. Moreover, the performance results both increased as the applied voltage was increased. With the use of the PID control, results showed an improvement of the performance ability that can reach the setpoint of 1, 2, 3 mm. Lastly, drug delivery tests combining hydrogel, IPMC and drug delivery device revealed unsatisfactory results. In the future, a more in depth discussion about the device performance in drug release test, like how much force can make hydrogel works, increase the thickness of IPMC films to improve the performance.

Ionic polymer metal composite (IPMC) is used in various bio-inspired systems, such as fish and tadpole-like robots swimming in water. The deflection of this smart material results from several internal and external factors, such as water distribution and surface conductivity. IPMC strips with a variety of water concentration on the surfaces and surface conductivity show various deflection patterns. Even without any external excitation, the strips can bend due to non-uniform water distribution. On the other hand, in order to understand the effects of surface conductivity in an aquatic environment, an IPMC strip with two wires connected to two distinct spots was used to demonstrate the power loss due to the surface resistance. Three types of input signals, sawtooth, sinusoidal, and square waves, were used to compare the difference between the input and output signals measured at the two spots. Thick (1-mm) IPMC strips were fabricated and employed in this research to sustain and drive the robot with sufficient forces. Furthermore, in order to predict and control the deflection, researchers developed the appropriate mathematical models. The special working principle, related to internal mobile cations with water molecules, however, makes the system complicated to be modeled and simulated. An IPMC strip can be modeled as a cantilever beam with loading distribution on the surface. Nevertheless, the loading distribution is non-uniform due to the non-perfect surface metallic plating, and four different kinds of imaginary loading distribution are employed in this model. On the other hand, a reverse-predicted method is used to find out the transfer function of the IPMC system according to the measured deflection and the corresponding input voltage. Several system-identification structures, such as autoregressive moving average with exogenous (ARX/ARMAX), output-error (OE), Box-Jenkins (BJ), and prediction-error minimization (PEM) models, are used to model the system with their specific mathematic principles. Finally, a novel linear time-variant (LTV) concept and method is introduced and applied to simulate an IPMC system. This kind of model is different from the previous linear time-invariant (LTI) models because the IPMC internal environment may be unsteady, such as free cations with water molecules. This phenomenon causes the variation of each internal part. In addition, the relationship between the thickness of IPMC strips and the deflection can be obtained by this concept. Finally, based on the experimental results above, an aquatic walking robot (102 mm × 80 mm × 43 mm, 39 g) with six 2-degree-of-freedom (2-DOF) legs has been designed and implemented. It walked in water at the speed of 0.5 mm/s. The average power consumption is 8 W per leg. Each leg has a thigh and a shank to generate 2-DOF motions. Each set of three legs walked together as a tripod to maintain the stability in operation.

Ionic polymer metal composites (IPMC) are a new class of smart materials that have attractive characteristics such as muscle like softness, low voltage and power consumption, and good performance in aqueous environments. Therefore, there is a significant motivation for research on design and development of IPMC based biomimetic propulsion systems for underwater vehicles. In aerospace, underwater vehicles finds application for forensic studies of spaceship wrecks, missile fragments and any airplane accidents in sea and ocean terrains. Such vehicles can also survey moons and planets that house water oceans. Among biomimetic swimming systems, fish inspired swimming has gained interest since fish like swimming provides high maneuverability, high cruising speed, noiseless propulsion and efficient stabilization compared to conventional propulsion systems. In this work, the paired pectoral fin based oscillatory propulsion using IPMC for aquatic propulsor applications is studied. Dynamic characteristics of IPMC fin are analyzed using numerical simulations and optimization is used to improve the fin design. A complex hydrodynamic function is used to describe the behavior of an active IPMC fin actuator in water. The structural model of the IPMC fin is obtained by modifying the classical dynamic equation for a slender beam to account for the electromechanical dynamics of the IPMC beam in water. A quasi-steady blade element model that accounts for unsteady phenomena such as added mass effects, dynamic stall, and the cumulative Wagner effect is used to estimate the hydrodynamic performance of the flapping fin. It is shown that the use of optimization methods can lead to significant improvement in performance of the IPMC fin. Further, three fish species with high performance flapping pectoral fin locomotion are chosen and performance analysis of each fin design is conducted to discover the better configurations for engineering applications. Dynamic characteristics of IPMC actuated flapping fins having the same size as the actual fins of three different fish species, Gomphosus varius, Scarus frenatus and Sthethojulis trilineata, are also analyzed. Finally, a comparative study is performed to analyze the performance of the three different biomimetic IPMC flapping pectoral fins.

This thesis deals with developing a thermodynamically consistent model to simulate the electromechanical response of ionic polymer-metal composites based on Euler-Bernoulli beam theory. Constitutive assumptions are made for the Helmholtz free energy and the rate of dissipation. The governing equations involving small deformations are formulated using the conservation laws, the power theorem, and the maximum rate of dissipation hypothesis. The model is extended to solve large deformation cantilever beams involving pure bending which could be used in the characterization of the material parameters. A linear finite element solution along with a staggered time stepping algorithm is provided to numerically solve the governing equations of the small deformations problem under generalized electromechanical loading and boundary conditions. The results are in qualitative and quantitative agreement with the experiments performed on both Nafion and Flemion based Ionic Polymer-Metal Composite strips.

碩士
中原大學
生物醫學工程研究所
98
The purpose of this study is to utilize lithography technology to fabricate ionic polymer-metal composites (IPMC) microfluidic pump. In addition, a finite element analysis program, i.e. COMSOL Multiphysics 3.5, was used to stimulate the electroactive deformation of IPMC membrane. The experiment was divided into four parts. First, IPMC membrane having different thickness and Pt/Au electrodes were prepared. Second, physical properties of IPMC membrane; the moisture content, the surface resistance and Young’s modulus were measured. Third, a computational model of IPMC membrane was established to evaluate the electroactive performance. The model considered the Fick’s law of ions and water molecules in IPMC membrane, Gaussian’s Law and generlized Hook’s law. Lastly, the IPMC membrane placed above a microfluidic chamber. In the electroless plating of IPMC membrane, an optimal surface resistance of 10 ohm could be reached after at least three cycles of the plating using gold complex salt. The maximum moisture content of IPMC membrane was about 19 to 20 %, and the moisture content and strain was linearly dependent. It was found that the optimal bending displacement of IPMC membrane was obtained in the following condition: wet, 0.1 N NaOH solution. Furthermore, a better displacement can be reached 4.38 mm when the membrane was soaked in o.1 N NaOH solution. The maximum displacements of Au electroded IPMC decreased about 61.5 % after sandwiched IPMC with PDMS membranes. In contrast, that of PDMS-laminated Pt-IPMC decreased to 28.5 % of original one. In the computational model, the IPMC cantilever beam electrically activated under a sine waveform of 3 Volt and 3 Hz showed a 0.7 fold of that of measured displacement. Finally, fabricated IPMC microfluidic pump was able to deliver deionized water under a driving condition of 5 volt and 2 Hz. However, the drawback of the pump was difficult fixed lead fluid leakage easily. This study has demonstrated a potential application of IPMC membrane in the microfluidic pump. It is expected that the performance of the IPMC microfluidic pump could be improved if the drwabacks are addressed, yet the IPMC micropumps are highly applicable to the implantable drug delivery system.

碩士
國立中正大學
機械工程系研究所
107
This paper is mainly to study the process and application of ionic polymer metal composites (IPMC), using the characteristics of rapid deformation and high momentum of components and using magnetic clamps to make different applications and tests. In terms of process, the paper is for IPMC. The actuator's yellow lithography process and component electrode process are fully described. This paper is different from the previous use of traditional wood clips to power the IPMC actuators. The 3D printing fixture is matched with the magnet suction to make appropriate combinations of the component contact surfaces to reduce the possibility of component damage. First, we added a serpentine shape to the zone plate structure, and used IPMC to push the center point to change the focus position. In the infrared analog control part, we used SMD-LED instead of infrared light, and connected the IPMC upper and lower poles with serpentine-shaped connecting wires. Make a lift and take off and light and dark control of the LED lights. Finally, a stretchable grating was fabricated by using PDMS, and the copper clasp was used to bond with the IPMC, and the slit pitch was changed and the position of the light was observed to be shifted.

碩士
國立臺灣大學
光電工程學研究所
100
Traditionally, the flexible thin-film device, IPMC, can only be used as an actuator due to its rough metal surface. Our goal is to provide an electro-chemistry optical actuator with smooth mirror surface and a voltage-controlled flexible polymer substrate for reconfigurable antenna. These are new application in aspect of optical system for free from surfaces and communication device designs just like antenna on micro-electro-mechanical systems (MEMS). When traditional Pt-IPMC is approaching to its optical and mechanical limits, introduction of performance boosters by alternative materials or novel surface treatments has become necessary. With high reflectance, low resistance and low-cost, Cu has become a very promising candidate to be used in MEOMES. In this thesis, by a low-temperature process, including adhesion metal electrode bonding and surface treatments, high-quality Cu electrodes were successfully integrated onto flexible N117 substrates by effective electroless deposition process. It was found that the insertion loss (I.L.) of Cu electrodes with N117 substrates was dramatically decreased for the 1550nm incidence infrared. Additionally, the optical characters of surface roughness (Rq) for thin IPMC film would be characterized by optical white-light interferometer to produce high quality two-dimensional surface maps of the IPMC. Moreover, the voltage-controlled flexible polymer substrate for reconfigurable antenna is also an important issue. In this thesis, the actuation resistance and working voltage of the Pt-IPMC antenna with EMI-Tf electrolyte are characterized. Finally, we apply the 1st generation Pt-IPMCs and the 2nd generation Cu-IPMCs on strain response test for mechanical properties measurements. The Young’s modulus of the 2nd generation Cu-IPMC is less than the 1st generation Pt-IPMC, and proper surface treatments also further boost the reflectance enhancement. In addition, N117 substrates exhibit flexible characteristics and provide tremendous chemical stability. These results suggest that the IPMC could be promising for inexpensive MEMS devices and applicable on other large area nanostructure-based optoelectronics devices for MOEMS.