Single-walled carbon nanotubes / polymer nanocomposites microbeams by means of ultraviolet-assisted direct-write assembly

We report the successful fabrication of nanocomposite microbeams by means of ultraviolet-assisted direct-write assembly. The nanocomposite consists of a UV curable resin reinforced by single-walled carbon nanotubes (C-SWNTs). The C-SWNTs were produced by the UV-laser ablation method, physico-chemically purified and dispersed in the polymer matrix using sonication in dichloromethane. The as-grown and purified C-SWNTs were systematically characterized by microRaman and photoelectron spectroscopy. Carboxyl groups were attached to the C-SWNT during the purification procedure. Eight different nanocomposite blends were produced from as-grown and purified CSWNT at varying concentrations. The UV-assisted direct-write approach consists of the robotically-controlled micro-extrusion of the C-SWNT/polymer nanocomposite under UV exposure. Cylindrical microbeams were deposited in a layer-by-layer mode and in a freeform fabrication fashion in order to achieve a mechanical testing micro-coupon. A comprehensive study under dynamic mechanical analyzer was performed on microrods (diameter (d) of ̃200 um) spanning a distance (Z.) of 3 mm for an aspect ratio (L/d) of 15. An increase by ̃63% in strength and ̃47% in modulus is measured for the microbeams using the 0,6wt% purified C-SWNT reinforcement.