E. Umana

All-Organic Motion Sensors: Electromechanical Modeling

A new class of materials called ionic polymer-polymer composites has been investigated to demonstrate the sensing and acting capabilities of these all-organic structures. Samples have been realized by covering Nafion membranes, with Orgacon 3040 conducting polymer as electrode material. Membranes whose electrodes were manufactured using the drop-casting technique exhibited the best electromechanical performances. Sensors have been tested in a dedicated experimental setup to model their electromechanical transduction behavior. Thus, the obtained model has been validated.

On the way to plastic computation

The development of post silicon technologies based on organic materials consolidates the possibility to realize new devices and applications with unusual properties: flexibility, lightweight, disposability. Both materials and processes play a fundamental role in this new electronic framework and have been improved continuously in the last decades. In this contribution, a new perspective will be drawn by considering a complete technology platform that lead printed organic electronics technology from the basic device and materials to a manufacturing process flow, design tools and market applications development. The final goal of the proposed approach is the manufacturing of organic circuits with sub-micron feature size at low fabrication costs with high flexibility and application versatility by using additive manufacturing processes. The identification of suitable material features and process steps and the implementation of dedicated CAD tools in a complete workflow are here reported. Moreover, the feasibility of the adopted technology is demonstrated by the design of both digital and analog circuits. Multilayered structure devices, like organic thin film transistor (OTFT), are used to design complex architectures like arithmetic logic units and nonlinear oscillators.

A study on IP2C actuators using ethylene glycol or EmI-Tf as solvent

Ionic polymer–polymer composites (IP2Cs) are a novel class of all-organic electroactive polymers that can operate both as electromechanical actuators and as sensors. They are an evolution of ionic polymer–metal composites (IPMCs), since the metallic layers, used to realize the electrodes, are substituted by using organic conductors based on PEDOT:PSS. For the IPMC based actuators it is generally reported that solvents different from water can be used to avoid the dehydration phenomenon. Here the possibility to use ethylene glycol and an ionic liquid, 1-ethyl-3-methylimidazolium trifluoromethanesulfonate, as diluents for the IP2C is investigated. Moreover, different materials have been used for the manufacture of the device electrodes and the performances of different organic transducers have been observed and compared. Reported results show that the use of both ethylene glycol and EmI-Tf as the solvent can have beneficial effects both on the working time duration of IP2C and on the corresponding transduction behaviors.

All organic actuation and sensing devices

In this work, all-organic structures with sensing and acting capabilities are prepared and tested. The devices have been realized by covering Nafionreg membranes with conducting polymers as electrode elements. The selection of both the materials and the deposition techniques has been addressed taking into account the chemical-physical characteristics of the membrane. Several tests have been performed in order to characterize both the morphological and electrical behavior of the obtained structures. The results show that it is possible to produce all-organic devices based on Nafionreg that have electromechanic transduction capacities. The possibility to use these devices both as sensing and acting elements has been demonstrated.

An investigation of the structure?property relationships in ionic polymer polymer composites (IP2Cs) manufactured by polymerization in situ of PEDOT/PSS on Nafion?117

Ionic polymer polymer composites (IP2Cs) are all-organic electroactive polymers (EAPs) that show sensing and actuation capabilities when a deformation or a voltage is applied, respectively. They are fabricated starting from an ionic polymer coated on both sides with a conducting polymer as electrode element. In this work, poly(3,4-ethylendioxytiophene)–poly-(styrenesulfonate) (PEDOT/PSS) has been polymerized directly on Nafion®117 membrane and devices have been manufactured varying the polymerization time. Water and ethylene glycol (EG) have been used as solvents. The obtained IP2Cs have been characterized using thermal and mechanical analyses and electromechanically tested. The results have shown that in IP2Cs manufactured by polymerization in situ the PEDOT/PSS layer adheres very strongly on the Nafion®117 film, improving the possibility of rehydrating the devices after use. Moreover, taking into account that the different polymerization times influence the uniformity of the surface of the organic electrode and, consequently, both device stiffness and electrode conductivity, the structure–property relationships of the obtained devices have been investigated. The influence of the different solvents inside the devices has also been studied when IP2Cs have been used as actuators or sensors. Reported results show that it is possible to modulate the performances of IP2Cs by varying some manufacture parameters and the solvent.

A multi-physics model of an IPMC actuator in the electrical, chemical, mechanical and thermal domains

IPMCs are electroactive polymers which can be used both as sensors and as actuators. A multiphysics model of IPMC devices working as actuators is here presented. The model integrates electrical, mechanical, chemical and thermal effects in a unique solution and attention is focused on the coupling factors among the physics domains. The model was validated through experimentation.

A Multiphysics Frequency-Dependent Model of an

Ionic polymer-polymer composites (IP2Cs) are electroactive polymers which can be used both as sensors and as actuators. In this paper, a new multiphysics model of IP2Cs working as an actuator is presented and implemented using a finite element methods solver (COMSOL Multiphysics). The model involves electrical, mechanical, chemical, and thermal effects and yields a unique solution. Knowledge acquired by measuring campaigns has been included in the model. More specifically the frequency dependence of Youngs modulus was experimentally determined and introduced in such a model. A frequency-domain investigation is performed and a model optimization procedure that integrates the Nelder-Mead simplex method with the COMSOL Multiphysics models is exploited to identify IP2C model parameter by fitting experimental data. A fractional order dynamics has been identified in the model, confirming previous studies on IPMC gray box modeling and on electroactive polymeric devices.

{\rm IP}^{2}{\rm C}

In this paper, a seismic sensor based on the combination of ionic polymer metal composite (IPMC) and ferrofluids is presented. The device consists of a vial, filled with ferrofluid, housing an IPMC cantilever beam sensor. Considering that the behavior (e.g., frequency response) of a beam immersed in a fluid changes with the fluid density, in this paper, a novel methodology is proposed to implement a mechanism allowing for the active tuning of the sensor specifications (such as operating range, frequency behavior, and responsivity). To such aim, the addressed methodology exploits external magnetic fields to modify the density of the ferrofluid in which the IPMC sensor is immersed. A description of the sensing methodology and the realization of the sensor prototype are given along with experimental results confirming the expected behavior of the device. Moreover, a model is presented which can be used to predict the IPMC behavior as a function of the fluid properties.

Actuator

In this paper different strategies to model Ionic Polymer-Polymer Composite (IP2C), used as actuator, are compared. Starting from some previous results regarding the ionic polymer metal composites (IPMCs) modeling, a linear gray-box model has been determined for an IP2C actuator. Moreover linear and nonlinear black-box models have been identified from experimental data. A comparison among developed models has been performed in order to determine the model that better describes the actuator behaviour.

A Seismic Sensor Based on IPMC Combined With Ferrofluids

In this paper, an entire organic Chuas circuit is presented. The adopted technology is one of the most advanced in the post-silicon era and extends the applications of classical silicon devices. The electronic circuit design is based on Organic Thin-Film Transistors (OTFTs). New electronic blocks based on OTFT are designed to be suitable with the organic technology features. Typical dynamics of the Chuas circuit have been reproduced.