Tridimensional microstructures of c-swnt reinforced polymer nanocomposite by means of a microfluidic infiltration approach

Three-dimensional (3D) microstructures of single walled carbon nanotube (C-SWNT)/polymer nanocomposite are fabricated by the infiltration of 3D microfluidic networks. The microfluidic network was first fabricated by direct-write assembly which consists of the robotised deposition of fugitive ink filaments on an epoxy substrate to form a 3D microstructured network. After encapsulation of the deposited structure with an epoxy resin, the fugitive ink was removed by heating, resulting in a 3D network of microchannels. This microfluidic network is then infiltrated by an ultraviolet (UV) -curable polymer loaded with C-SWNTs. The C-SWNTs were produced by the UV-laser ablation method, physico-chemically purified and dispersed in a polymer matrix using ultrasonic treatment in dichloromethane. The C-SWNTs were characterized by microRaman spectroscopy. The infiltrated nanocomposite (i.e., the C-SWNT reinforced polymer) is then cured under UV exposure and post-cured. The manufactured 3D microstructures were rectangular sandwich beams having an epoxy core and unidirectional nanocomposite fibers placed parallel to the beam axis, on both sides of the core. Flexural mechanical tests were performed on empty, pure resin and nanocomposite microfluidic beams using a dynamic mechanical analyzer. The achieved nanocomposite beams were found to show an increase of 5% in the storage modulus and more than 50% increase in the loss modulus, under 30°C compared to the pure resin beams. The nanocomposite infiltration of microfluidic networks is shown to be a promising approach to achieve 3D nanocomposite microstructures.