Actuator conjugated polymer-based

In Chapter 9, we move on to discuss a few device and robotic applications of EAP materials, by drawing heavily on the advances in material development and modeling that are discussed in prior chapters. These application examples include a robotic fish propelled by an IPMC tail, an IPMC energy harvester, an IPMC-based valveless pump, a conjugated polymer petal-driven micropump, and a synthetic elastomer actuator-enabled robotic finger. Most discussions of these examples are supported with extensive experimental results. 

Secondly, conjugated polymers were studied as biomimetic artificial muscles. A scalable physics based electro-chemo-mechanical model was developed to connect an input voltage to bending of the material. The reduced version of the model was used to design a robust adaptive controller. Also, a nonlinear mechanical model was investigated. Furthermore, a torsional actuator was developed by depositing PPy on a tube substrate with helically wound platinum fibers. A set of experiments were conducted to confirm the torsional and other actuation modes as well as the model. 

Langmaier J, Opekar F, Samec Z (1997) Amperometric solid-state NO sensor based on plasticized PVC matrix containing a hydrophobic electrolyte. Sens Actuators B 41 1-6 Leclerc M (1999) Optical and electrochemical transducers based on functionalized conjugated polymers. Adv Mater 11 1491-1498... 

Prasad GK, Radhakrishntm TP, Kumar DS, Krishna MG (2(X)5) Ammonia sensing characteristics of thin film based on polyelectrolyte templated polyaniline. Sens Actuators B 106 626-631 Pron A, Rannou P (2002) Processible conjugated polymers from organic semiconductors to organic metals and superconductors. Prog Polym Sd 27 135-190... 

Tan CK, Blackwood DJ (2000) Interactions between polyanUine and methanol vapour. Sens Actuators B 71 184-191 Thomas SW III, Joly GD, Swager TM (2006) Chemical sensors based on amplifying fluorescent conjugated polymers. Mater Sci Eng R 52 49-91... 

Companies dedicated to the development of artificial muscles based on conjugated polymers have also emerged in recent years. MicroMuscle based in Sweden and EAMEX from Japan are both actively pursuing actuators for biomedical and electronics apphcations. Santa Fe Science and Technology, USA, has produced continuous spun polyaniline fibres and demonstrated their use as linear actuators [11, 12]. Academic laboratories have also developed several demonstration products including a variable camber hydrofoil [13], a robotic fish propulsor fin [14], a gas valve [15], microrobots [16] and a micropump [10], some of which are illustrated in Figure 10.1. An electronic Braille screen using ICP actuators is also described in this book [17]. 

IPMC actuators exhibit a typical strain of 0.5 %, strain rate of 3 %/s and a typical stress of 3 MPa. They are actuated at potentials of <10 V [42]. The performance of these actuators has been improved by using various combinations of cations [23-25] and different types of electrodes, such as platinum-copper [26]. In this chapter a brief overview of different designs and test procedures using this type of actuators is presented, as similar approaches could also be employed in conjugated polymer driven devices. IPMC based steerable catheters are further described in another chapter of this book. 

As mentioned previously, one of the most important and exciting advantages of conjugated polymer microactuators is the possibility of integrating them into more complex microsystems, such as the cell-based sensors described above. The actuators add the powerful capability of mechanical manipulation of biology on the microscale. This is enabled by their low voltage operation and room temperature microfabrication, and the wide variety of actuator configurations that are possible. 

Smela, E., Christophersen, M., Prakash, S. B. (2007) 12 14 Oct. Integrated cell-based sensors and cell clinics utilizing conjugated polymer actuators, SPIE 14th Annual International Symposium on Smart Structures and Materials, Electroactive Polymer Actuators and Devices (EAPAD), San Diego, CA, 6524 (ed. Bar-Cohen, Y.), OG 1 10. 

In the near future, further development in new soft microelectrochemical devices based on conjugated polymer actuators will require their complete conception, operation, and interfacing systems all integrated on a single substrate to allow easy and independent operation. This still poses a real challenge that remains to be overcome. Also, it would be of great interest to develop microactuators with linear actuation to further extend the tool box of CP microactuator devices. 

---