Browsing by Author "Kuusisto, Eero"
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- Development and realization of piezo jet printed electroactive polymer actuators
Kemian tekniikan korkeakoulu | Master's thesis(2023-01-24) Kuusisto, EeroIn various studies, electroactive polymer sensors and actuators have been fabricated by screen printing and other film deposition methods. While they are suitable for large constant patterns, their downside is the slow tunability of the process and wasting material while spreading excess ink over the area. This thesis presents an easily controllable fabrication method for producing precisely shaped electroactive polymer actuators. The method combines two ink-on-demand printing methods, piezo jet printing for the functional electroactive polymer layer and aerosol jet printing for electrode layers. The layouts were designed with a CAD/CAM software, and the actuators are transparent and have precise shapes with exact thicknesses. The printing parameters were optimized, and the ink was deposited only to the wanted areas. After printing, the samples were annealed and polarized to form correctly aligned crystals in the polymer, enabling the actuator functionality. The visual sample quality was analyzed with a confocal scanner and a scanning electrode microscope. The electrical properties of the samples were measured with a multimeter to ensure they worked capacitively, and finally, the actuation properties were measured with a vibrometer. The development of electroactive polymer actuators is presented for the first time by piezo jet printing. The results show that electroactive polymer actuators can be fabricated with this method with >2 µm actuation, which is double the human fingertip threshold of sensing. The tunability and precision make them feasible to be used in applications needing various shapes, such as surface haptic applications. - Inkjet-printed flexible silver electrodes on thiol-enes
A1 Alkuperäisartikkeli tieteellisessä aikakauslehdessä(2021-06-01) Kuusisto, Eero; Heikkinen, Joonas J.; Järvinen, Päivi; Jokinen, VilleFlexible and conductive silver electrodes were fabricated by inkjet printing on several different compositions of thiol-ene polymers. Conductive electrodes with resistivity down to 30 µΩcm and good adhesion of the electrodes were obtained by optimizing the printing parameters. The maximum printing resolution was 100 µm lines and 80 µm gaps between the lines. Printing on top of cross-linked off-stoichiometric thiol-ene polymer was tested for compositions ranging from 30 % thiol excess to 5 % allyl (‘ene’) excess. The roughness off the thiol-ene surfaces was shown to greatly improve the quality of the printed electodes: consistently high yield of conductive electrodes was obtained on rough surfaces (roughness ≈ 1 µm), whereas on smooth surfaces the electrodes were often cracked. The lowest resistivity values were obtained on electrodes printed on near stoichiometric thiol-ene substrates. The conductivity of the electrodes was retained after 5 % linear strain and after repeated bending with 1 mm radius of curvature, showing the potential for flexible sensors. The electrodes were also applied to electrical impedance-based monitoring of cell growth on thiol-ene surfaces, which showcased that the electrodes survive stressed cell culture conditions for at least 36 h. - Mikro- ja nanorakenteiset jäänestopinnat
Kemiantekniikan korkeakoulu | Bachelor's thesis(2020-05-25) Kuusisto, Eero