Carbide-derived carbon-based electromechanical actuators
Date
2012-06-28
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Abstract
Doktoritöö raames uuritud nanopoorsetel süsinkmaterjalidel põhinevate elektroaktiivsete kilede, kui elektrivoolu toimel kiirelt ja hääletult kuju muutvate materjalide näol on tegemist seni veel väikesemahulise, kuid kiirelt areneva valdkonnaga. Paljuski analoogne käitumine lihaskoega on põhjuseks, miks neid kuju muutvaid täitureid on nimetatud ka tehislihasteks ja just nimelt selle analoogia põhjal nähaksegi materjalide võimalike rakendusvaldkondadena robootikat ja meditsiinitehnoloogiat.
Väitekirjas vaadeldi detailsemalt poorsel süsinikmaterjalil ja polümeeril põhinevate kihiliste täiturite elektromehaanilisi omadusi lineaarsel- ja paindeliigutusel ning keskenduti põgusalt ka materjalide võimalikele kasutusvaldkondadele. Erinevate karbiidset päritolu süsinike lisamisel täituri elektroodide koostisesse täheldati süsinikmaterjali poorsusest ja eripinnast tulenevat mõju täituri elektromehaanilistele parameetritele.
TiC-st, B4C-st ja Mo2C-st sünteesitud süsinikpulbritel põhinevatel painduvatel täituritel leiti, et elektrilise pinge rakendamisel tekitatava liigutuse ulatus ja liigutuse kiirus kasvavad vastavalt suurenevale mesopooride hulgale elektroodkihis. Kuldfooliumiga modifitseeritud täiturite elektrokeemilised ja elektromehaanilised mõõtmised kinnitasid tähelepanuväärset kasvu liigutusulatuses ja sealjuures täheldati tööpinge alanemist kuni 0.25 voldini.
Käesoleva töö raames läbiviidud katsed näitasid, et karbiidset päritolu süsinikmaterjalid on sobilikud elektromehaaniliste täiturite rakendustes, kus eeldatakse suurt täpsust ja piisavat kontrolli materjali liigutusulatuse üle. Täiturite liigutusomadusi, samuti ka energiatarvet saab modifitseerida, kasutades elektroodkihis erineva poorijaotuse ja eripinnaga karbiidset päritolu süsinikmaterjale. See unikaalne omadus koos materjalide lihtsa valmistamismeetodi, täituri suure paindeulatuse, madala tööpinge ja täituri elektroodide suure erimahtuvusega pakub kasutusvõimalusi mitmetes rakendustes nagu tehislihased või hübriidsed elektromehaanilised täiturid ja energia muundamise seadmed.
A major goal in soft polymeric electromechanical actuator research is to develop a device that operates rapidly with high displacement at low voltage applied, and has low energy consumption at the same time. Current technologies based on electromotors and pneumatic actuators make the final product often too noisy, heavy and too complicated. For that reason a notable demand exist for soft, simple and miniature actuation devices in many technological solutions. For robotics and medical applications a desired actuation source should guarantee steady operation in different environments. This thesis introduces experiment series carried out for carbide-derived carbon (CDC) based actuator devices in order to study relations between porosity parameters onto generated strain of actuators. In linear actuator configuration the effects based on charge induced volumetric expansion of electrolyte impregnated CDC electrodes were investigated. Test cells with different electrolytes were assembled and electromechanical response was characterized. Dry-type bending actuators which had three layer configuration of two polymer supported carbonaceous electrodes and thin polymeric membrane between them were developed and analyzed. In addition to electromechanical characterization, electrochemical measurements were simultaneously carried out to describe energy consumption of both CDC-based actuators. The studies have pointed out that actuators with gradual displacement/strain characteristics can be prepared from wide selection of precursor carbides available to determine porosity of final carbon material and therefore influence the performance of actuators based on CDC. This unique property together with their facile preparation method, flexibility, remarkable specific capacitance, and low driving voltage enable the CDC-based actuators application in many areas such as artificial muscles, and hybrid actuator/energy conversion devices.
A major goal in soft polymeric electromechanical actuator research is to develop a device that operates rapidly with high displacement at low voltage applied, and has low energy consumption at the same time. Current technologies based on electromotors and pneumatic actuators make the final product often too noisy, heavy and too complicated. For that reason a notable demand exist for soft, simple and miniature actuation devices in many technological solutions. For robotics and medical applications a desired actuation source should guarantee steady operation in different environments. This thesis introduces experiment series carried out for carbide-derived carbon (CDC) based actuator devices in order to study relations between porosity parameters onto generated strain of actuators. In linear actuator configuration the effects based on charge induced volumetric expansion of electrolyte impregnated CDC electrodes were investigated. Test cells with different electrolytes were assembled and electromechanical response was characterized. Dry-type bending actuators which had three layer configuration of two polymer supported carbonaceous electrodes and thin polymeric membrane between them were developed and analyzed. In addition to electromechanical characterization, electrochemical measurements were simultaneously carried out to describe energy consumption of both CDC-based actuators. The studies have pointed out that actuators with gradual displacement/strain characteristics can be prepared from wide selection of precursor carbides available to determine porosity of final carbon material and therefore influence the performance of actuators based on CDC. This unique property together with their facile preparation method, flexibility, remarkable specific capacitance, and low driving voltage enable the CDC-based actuators application in many areas such as artificial muscles, and hybrid actuator/energy conversion devices.
Description
Väitekirja elektrooniline versioon ei sisalda publikatsioone.
Keywords
ajamid, süsinikmaterjalid, nanopoorsed materjalid, actuators, carbon materials, nanoporous materials