Electro-Active Paper Material Research Articles

Analytical and experimental investigation of partially covered piezoelectric cantilever energy harvester

Electrical energy is normally generated through different sources such as hydroelectric, wind, heat, nuclear transformation, chemical reactions or vibrations. Nowadays, harvesting power from mechanical vibration is one of the novel technologies that usually can be done by systems based on electromagnetic, electrostatic, piezoelectric and combination of them. Piezoelectric systems can convert motion from the vibrating structures into electrical power. Cellulose Electro-active paper (EAPap) has been recognized as a novel smart piezoelectric material that can be used for energy harvesting purposes. One of the most prevalent method for vibration energy harvesting is using unimorph piezoelectric cantilever beams. In this paper, an analytical solution based on distributed parameter model is presented to calculate the generated energy from vibration of cantilever substrate that is partially covered by EAPap material. In the studied structure, piezoelectric layer thickness in comparison to the length of the beam and thickness of substrate material can be considered very thin. Thus its effect on the vibration behavior of structure is negligible. The results are validated by experimental values. The analytical data was found to be very close to experimental results and finite element simulation values. Findings from this study provide guidelines on system parameters that can be manipulated for more efficient performance in different ambient source conditions.

Sonication time effect on MWNT/PANI-EB composite for hybrid electro-active paper actuator

This paper investigates the multi-walled carbon nanotubes (MWNT) and emeraldine formed polyaniline (PANI-EB) composite coating on electro-active paper (EAPap) actuator. EAPap is made with a cellulose paper by coating thin electrodes on both sides of the paper. When an electric field is applied across the electrodes the paper generates a bending displacement. This EAPap material has merits in terms of lightweight, low actuation voltage, low power consumption, dryness, biodegradability and low price. However, the force output and the actuation frequency band are low. Thus, the MWNT with PANI-EB composite is coated on EAPap material to improve its performance as an actuator. This is termed as a hybrid EAPap actuator. The fabrication process of the composite and the actuator performance are explained. In the fabrication process of the composite, the weight percents of MWNT and PANI-EB, and the sonication time have significant effect on the characteristics of the composite as well as the performance of the hybrid EAPap actuator. The weight percents of MWNT and PANI-EB were chosen by considering the electrical property as well as the process capability of the composite. The composites are made with different sonication times, from 2 h to 5 h, and their characteristics are analyzed using FT-IR, TGA, SEM and electrical conductivity measurement. The structural enhancement and electrical conductivity change associated with the sonication time are explained based upon the strong bonding and ionic interaction of MWNT and PANI-EB constituents. Based on the analysis results of the composite, the actuation performance of the hybrid EAPap actuator is evaluated in terms of bending displacement, blocking force, electrical power consumption and efficiency along with sonication time.

Piezoelectric Effect of Electro-Active Paper Materials

The application of electroactive polymer devices requires the availability of their properties at various operating conditions. This in turn necessitates a structure-property relationship based on an in-depth understanding of the underlying mechanism responsible for their strain-field response. Cellulose-based Electro-Active Paper (EAPap) has been studied as an attractive Electro Active Polymer (EAP) material for artificial muscles. The feasibility of EAPap material as an actuator/sensor application is greatly dependant on piezoelectric effect. In this paper, converse and di rect piezoelectric ef fect s of Electro-Active Paper materials are studied to characterize piezoelectric effects of EAPap. All experiments were conducted in an environmental chamber that can control temperature and humidity.

Hybrid Electro-Active Papers of Cellulose and Carbon Nanotubes for Bio-Mimetic Actuators

Electro-Active Paper (EAPap) materials based on cellulose are attractive for many applications because of their low voltage operation, lightweight, dryness, low power consumption, bio-degradability. The construction of EAPap actuator has been achieved using the cellulose paper film coated with thin gold electrode layers. This actuator showed a reversible and reproducible bending movement. In order to improve both force and displacement of this, efforts are made to construct hybrid EAPap actuators using cellulose paper coated with carbon nanotubes (CNT). To coat the CNT, single-walled carbon nanotubes (SWCNT) and multi-walled carbon nanotubes (MWCNT) are dispersed in polyaniline (PANI) matrix, and the solution is coated on the EAPap by using a spin coater. It is expected that the use of CNT can improve the force output by enhancing the stiffness of the hybrid EAPap actuator. Furthermore, the presence of the PANI may improve the actuation performance of the EAPap material. The performance of hybrid EAPap actuators is tested in an environmental chamber in terms of free displacement, blocked force and electrical power consumption. The performance of hybrid actuators is investigated for bio-mimetic applications.

Performance of Electro-Active Papers Made with Cellulose and Multi-Walled Carbon Nanotubes

Cellulose-based Electro-Active Paper (EAPap) has been studied as an attractive electroactive polymer material for artificial muscles due to its low cost, availability, lightweight, large displacement output, low actuation voltage and low power consumption. However, the force output of EAPap is small since paper is so flexible that the bending stiffness is low. In this paper, the cellulose based EAPap material is enhanced by using carbon nanotubes with cellulose paper. Coating of multi-walled carbon nanotubes mixed with polyaniline on EAPap as well as MWNT dispersion in the paper are tried to enhance the force output of the EAPap. The coating process of MWNT/PANI on the EAPap and the dispersion of MWNT in the cellulose paper are explained. The performance of the hybrid EAPap actuators is evaluated in terms of tip displacement, blocking force and electrical power consumption. The power output and the actuator efficiency are improved.

Multiwalled-carbon nanotubes and polyaniline coating on electro-active paper for bending actuator

Multi-walled carbon nanotubes (MWNT) and polyaniline are coated on an electro-active paper (EAPap) to improve the performance of the bending actuator, and its performance is tested. EAPap actuators made with cellulose paper have merits in terms of large bending displacement, ultra-lightweight, dryness, low actuation voltage and power consumption, low cost and biodegradability. However, the force output of actuators is small and the actuation frequency is low. Thus, MWNT and emeraldine salt polyaniline (PANI) are coated on the EAPap material to improve the force and the actuation frequency. The MWNT and PANI solution is made by sonication, and the sonication time and the weight per cents of the MWNT and PANI are optimized to improve the hybrid actuator performance. The optimum condition is associated with conversion of the partial conductive state PANI into the emeraldine formed PANI by the chemical bonding between the MWNT and PANI. The performance improvement of the EAPap actuator coated with MWNT/PANI is investigated in terms of displacement, blocking force and efficiency. In the presence of an electric field (0.35 V µm−1) on the hybrid EAPap actuator, 250% of the output force, 160% of the resonance frequency and 50% of efficiency are improved.

Micro transfer printing on cellulose electro-active paper

A micro-patterning technique regarded as micro transfer printing is studied for goldelectrode patterning on cellulose electro-active paper (EAPap), aiming at biodegradableand flexible MEMS fabrication. EAPap is known as a smart material due to the interestingactuation phenomenon of cellulose paper. Accordingly, EAPap can be used for sensor andactuator devices. Since EAPap is made with cellulose, a biodegradable and flexible MEMSdevice can be made with this material. However, since cellulose-based EAPap ishydrophilic and flexible, conventional lithography and etching techniques cannot beused for micro-patterning. This paper reports a new micro-patterning techniqueusing the micro transfer printing (MTP) method on flexible EAPap material. TheMTP technique consists of a master fabrication, a polydimethylsiloxane (PDMS)stamp construction, and a micro pattern transfer. Details of the technique and keyissues are addressed. To demonstrate the feasibility of the MTP technique, a goldelectrode pattern for a surface acoustic wave (SAW) MEMS device and a goldmicro-strip pattern for a microwave dipole rectenna are made on cellulose papersubstrates.

Performance of Electro-active paper actuators with thickness variation

This paper investigates the performance of electro-active paper (EAPap) actuators with thickness variation. EAPap made with cellulose paper, is attractive for biomimetic actuators due to its characteristics in terms of lightweight, biodegradable, dry condition, large displacement output, low actuation voltage and low power consumption. EAPap actuators exhibit a bending deformation in the presence of electric field. However, the performance is sensitive to the thickness of the EAPap material because the thickness is associated with the bending stiffness that strongly affects the bending deformation and the force output of the actuator. Thus, the performance of EAPap actuators that have three different samples of 20, 30, and 40 μm thicknesses is tested in terms of tip displacement, blocked force, electrical power consumption, and the efficiency. The sample preparation and the test methods are addressed. The resonance frequency and the bending stiffness are associated with the thickness of the EAPap actuator, and there is an optimum thickness for the best performance of the EAPap actuators. The mechanical output power and the efficiency at an optimal thickness are drastically improved comparing with the previous thickness case.