This article focuses on the preparation of extrusion printing composite inks of multiwall carbon nanotube (MWNT) dispersed separately in iota-carrageenan (IC) and glycerine (G) solution. Both composites (IC-MWNT and G-MWNT) showed shear-thinning behavior when their flow characteristics were tested. Conductive solid tracks/patterns of both printed composite inks were deposited on glass slide, PET (polyethylene terephthalate) sheet, and IC gel films substrates. The conductive patterns were characterized with microscopy, scanning electron microscopy (SEM), and profilometer. Moreover, their contact angle and electrical conductivity were measured. Profilometry showed that increased number of extruded layers gave increased cross-sectional area. SEM study showed that printing ink is embedded into the surface of IC film, discontinuous on glass slide and smoother on PET sheet. Conductivity of IC-MWNT track was 9 ± 1 S/m and that of G-MWNT was 2942 ± 84 S/m on glass substrate of one layer thick. This is because fewer carbon nanotubes (CNT) are present in G-MWNT track as confirmed by SEM study. The nature of substrate also affects the conductivity of printed patterns. The impressive result of conductivity of printed patterns of composite inks can make them useful for bioelectronic application.
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