Soft actuators with ink-jet printed electrodes
Date
2018-10-27
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Abstract
Tuleviku biomeditsiini- ja robootikarakenduste täiturite jaoks on vaja usaldusväärseid, korratavaid ja skaleeritavaid valmistamismeetodeid. Johannes Gutenbergi näitel võib printimine ka tehislihaste tootmist revolutsioneerida: printimine võimaldab valmistada ühtlase paksuse ja keeruka mustriga täitureid. Selle doktoritöö raames arendati välja prinditud kolmekihilised kahest elektroodist ja neid eraldavast membraanist koosnevad juhtivpolümeeridel põhinevad täiturid. Tänu analoogsele käitumisele looduslike lihastega kutsutakse neid kuju muutvaid materjale ka tehislihasteks ning just selle funktsionaalse sarnasuse põhjal on tõenäolisteks rakendusvaldkondadeks robootika ja meditsiinitehnoloogia.
Prinditud mikrotäiturite elektrilisi, mehaanilisi ja täituromadusi saab muuta kolme peamise strateegia abil. Esiteks modifitseeriti selles doktoritöös kommertsiaalse juhtivpolümeertindi koostist, lisades sinna süsinikaerogeeli. Saadud juhtivpolümeer-süsinik-komposiidil põhineval täituril näitas võrreldes ainult juhtivpolümeertäituriga suuremat jõudu. Teiseks varieeriti täituromaduste täppisreguleerimiseks elektroodi paksust, mis oli vähemalt 20 kihi ulatuses lineaarses sõltuvuses kihtide arvust. Paksuse kasvades suurenesid ka täituri jõud, liigutusulatus, pinnajuhtivus ja mahtuvus. Kolmandaks häälestati täituri sooritusvõimet sobivate alus- ehk membraanimaterjalide valikuga. Nitriilbutadieenkautšukile prinditud õhukesel täituril oli lineaarses liigutusrežiimis suurusjärgu võrra suurem liigutusulatus võrreldes tööstusliku polüvinülideendifluoriidmembraaniga täituriga.
Selles töös näidati, et piisksadestusprintimise teel on võimalik valmistada pehmeid elektromehaanilisi süsteeme, hoolimata meetodi mõningatest piirangutest. Sobivalt valitud tindimaterjalid ja häälestatud printimisprotsess võimaldavad juba lähitulevikus valmistada pehmeid ja integreeritud elektromehaanilisi süsteeme täielikult printimise teel.
Future soft micro actuator applications for biomedical and soft robotic applications need reliable, repeatable, cost-effective and scalable production methods. As an example of Johannes Gutenberg, printing could also revolutionize the production of artificial muscles – printing allows fabrication of homogeneous actuators with intricate patterns. In this thesis technology for fabricating actuators composed of two conducting polymer-based electrodes and a membrane separating them was developed. The actuators change their shape in response to electrical stimuli. Due to this functional similarity to natural muscles, applications in the fields of medicine and robotics are possible. The properties of printed micro actuators are tunable using various strategies. First, the composition of the conducting polymer ink was modified by adding carbon aerogel to the mix. The resulting composite showed superior force compared to pure conducting-polymer actuators. Second, the electrode thickness was controlled to fine-tune the properties. Increasing the thickness also increased the force, strain and capacitance of the actuator and conductivity of the electrodes. Third, the actuator performance was tailored by the selection of various membrane materials. Printing on spin-coated membranes from nitrile butadiene rubber resulted in extremely thin trilayer actuators that had an order of magnitude higher linear strain compared to commercial polyvinylidene based actuators. This work has showed that despite the known limitations of drop-on-demand printing, it is possible to prepare soft electromechanical systems using this technology. With the selection of compatible materials, and by using various strategies to tune the functional properties of the composite towards more preferred outcome it will be possible in the nearest future to realize applications with fully printed and integrated soft electromechanically active components
Future soft micro actuator applications for biomedical and soft robotic applications need reliable, repeatable, cost-effective and scalable production methods. As an example of Johannes Gutenberg, printing could also revolutionize the production of artificial muscles – printing allows fabrication of homogeneous actuators with intricate patterns. In this thesis technology for fabricating actuators composed of two conducting polymer-based electrodes and a membrane separating them was developed. The actuators change their shape in response to electrical stimuli. Due to this functional similarity to natural muscles, applications in the fields of medicine and robotics are possible. The properties of printed micro actuators are tunable using various strategies. First, the composition of the conducting polymer ink was modified by adding carbon aerogel to the mix. The resulting composite showed superior force compared to pure conducting-polymer actuators. Second, the electrode thickness was controlled to fine-tune the properties. Increasing the thickness also increased the force, strain and capacitance of the actuator and conductivity of the electrodes. Third, the actuator performance was tailored by the selection of various membrane materials. Printing on spin-coated membranes from nitrile butadiene rubber resulted in extremely thin trilayer actuators that had an order of magnitude higher linear strain compared to commercial polyvinylidene based actuators. This work has showed that despite the known limitations of drop-on-demand printing, it is possible to prepare soft electromechanical systems using this technology. With the selection of compatible materials, and by using various strategies to tune the functional properties of the composite towards more preferred outcome it will be possible in the nearest future to realize applications with fully printed and integrated soft electromechanically active components
Description
Väitekirja elektrooniline versioon ei sisalda publikatsioone
Keywords
electroactive polymers, printing