Carbon Nanotubes/Epoxy Nanocomposites for UV-Assisted Direct-Write Fabrication of Microstructures: Mechanical and Rheological Studies

摘要

We report on the preparation of biofunctionalized single-walled carbon nanotube (BF-SWCNT)/epoxy nanocomposites with different mixing strategies. The SWCNTs were first purified by acidic treatment and then functionalized by grafting biomaterials onto the SWCNTs surface. The BF-SWCNTs were dispersed within an epoxy resin by means of ultrasonication and/or three-roll mixing methods. It is found that the mixing procedure consisting of ultrasonication and three-roll mixing is an effective method to disperse nanotubes within epoxy matrix. The biomaterialgrafting of SWCNTs surfaces along with their fair dispersion led to a significant increase of viscosity of the nanocomposite suspensions which enabled the UVassisted direct-write fabrication of microfibers suspended between two pads and 3D freeform helicoidal microsprings. Mechanical characterization of the slender microfibers (150 μm diameter) at a nanotube load of 1wt%, under tension revealed considerable increase in both modulus (by ～93%) and strength (by 75%) compared to the values for pure epoxy resin. These mechanical improvements are believed to be a consequence of the biomaterial-grafting of the nanotubes surfaces which facilitate load transfer and their fairly-dispersion into the epoxy matrix. The manufactured nanocomposite microstructures containing BF-SWCNT could find applications in biosensors, where other biomaterials and hazardous gaseous can be detected by affecting the electrical conductivity of nanotube-reinforced nanocomposite microstructures.