Let’s talk about liquids! They’re great, aren’t they? Well, some of them are. The problem is that it’s not always easy to tell the good liquids from the bad, as anyone who has ever stood over a mysterious puddle on the kitchen floor knows. Spilled glass of water, or dog accident? No one wants to get close enough to find out. Determining the nature of a liquid gets especially dicey in heavy industry, however, where many of the liquids used are highly toxic and using the wrong one could have much worse consequences than a ruined towel.
Can 3D printing help? Of course it can. Scientists have been experimenting with 3D printing and carbon nanotubes for a while, and researchers from Polytechnique Montréal recently used 3D printing to combine carbon nanotubes with a thermoplastic polymer, increasing electrical conductivity and creating a material that can monitor liquids in real time. In an experiment performed by Mechanical Engineering Professor Daniel Therriault and his research team, a material that looks like a simple cloth was 3D printed. An unidentified liquid was introduced to the cloth, which reacted to the liquid in a way that instantly allowed it to be identified as ethanol.
It sounds bizarre, but the process, which Therriault has patented, is surprisingly simple. A thermoplastic is liquified with a solvent, creating a porous liquid into which carbon nanotubes can easily be added, resulting in a highly conductive, viscous black nanocomposite ink. That ink can then be 3D printed; as soon as it comes out of the nozzle, the solvent evaporates and leaves behind a thin filament about the size of a hair, which is deposited a layer at a time.
There are several applications for which this technology could be used to great benefit. 3D printing, as we’ve seen in other cases, enables micro- and nano-scale manufacturing with a precision that’s never been possible with other methods. In addition, the ability to work with nanocomposite filaments at room temperature allows for the plastic material to obtain conductivity close to that of certain metals. Also, since the technology lets the geometries of the filaments be varied, they can be calibrated to read the different electrical signatures of the various liquids being monitored in industrial processes.
For example, one proposed idea is to manufacture pipes with flanges coated by a 3D printed nanocomposite material. The coating’s electrical signature would be specially calibrated according to the liquid being transported in the pipe, such as oil. If the pipe developed a leak and the oil touched the coated flanges, an alarm would sound, letting the leak be detected right away, before it could cause much damage.
Other possible applications of the technology involve smart textiles, electronics, and other types of sensors. Therriault and his team, which includes Kambiz Chizari, Mohamed Amine Daoud, and Anil Raj Ravindran, published the results in their research in a paper entitled “3D Printing of Highly Conductive Nanocomposites for the Functional Optimization of Liquid Sensors,” first released towards the end of 2016. You can access the full article here. Discuss in the Carbon Nanotubes forum at 3DPB.com.[Source: Polytechnique Montréal]