As shown in the figure, the researchers found that using high concentrations of cresol can disperse carbon nanotubes into ordinary plastics.
Professor Huang Jiaxing from Northwestern University used an inexpensive solvent called cresol, a common chemical commonly used in household cleaners, and used it to develop a method for making dispersed carbon nanotubes. No additives or harsh chemical reactions are required, only high concentration cresol modified nanotubes can be used.
What is even more surprising is that Professor Huang also found that as the concentration of nanotubes increases, the material changes from a dilute dispersion to a thick paste, and then to a self-standing gel, which finally becomes moldable and Molded kneaded dough.
'Due to its excellent mechanical properties, thermal and electrical properties, carbon nanotubes have attracted widespread attention in many applications, but after decades of research and development, some researchers are no longer so keen on these studies. Professor Huang Jiaxing from the Department of Materials Science and Engineering, Northwestern University's McCormick School of Engineering said.
The processing of carbon nanotubes has always been very difficult, especially in high-volume processing. According to relevant data, the tubular structure of carbon nanotubes is about 10,000 times thinner than human hair, but it is stronger than steel, and its heat and electricity. Conductivity is much better than copper. But when mass-produced (usually in the form of powder), the pipes are twisted and gathered together. This complex situation is the main problem that hinders the widespread use of this material.
'The aggregated pipes are difficult to disperse in the solvent. If the carbon nanotubes cannot be uniformly dispersed, the high quality nanotube film required for the application cannot be produced. Professor Huang explained that in order to solve this problem, researchers have used additives to coat nanotubes, thereby chemically modifying them and forcing them to separate. This method, although effective, leaves residues. Or change the surface structure of the nanotubes, thereby weakening its ideal properties.
In contrast, Professor Huang's team found that cresol does not destroy the surface function of carbon nanotubes. And, after separating the entangled tubes, the researchers can simply remove the chemicals by washing or heating until the solvent evaporates. .
After unlocking a new way to make high-concentration carbon nanotubes, Professor Huang and his team discovered a new form of this material. As the concentration of carbon nanotubes increases, the material changes from a dilute dispersion to a smear-like paste, which turns into a self-standing gelatinous shape, which eventually becomes a kneaded dough. These different forms can be molded. , reshaped or used as a conductive ink for 3D printing.
'The dough state of nanotubes is very fascinating. Just like plasticine, it is easy to shape and can be shaped into any structure.' Professor Kevin Chiou, a graduate student at Professor Huang's laboratory and the first author of the paper.
'In essence, this solvent system makes nanotubes behave like polymers, especially when phenol-based solvents make once difficult to process carbon nanotubes become as common as ordinary plastics. Excited. 'Professor Huang said.