"Our results suggest new alternatives for fabricating nanotube patterns by simply printing the dissolved particles on paper or plastic surfaces," said Robert Vajtai, a researcher with the Rensselaer Nanotechnology Center at Rensselaer Polytechnic Institute and corresponding author of the paper. But most current techniques to make nanotube-based devices require complex and expensive equipment. The method, which is described in the August 2006 issue of the journal Small, could lead to a new process for manufacturing a wide range of nanotube-based devices, from flexible electronics and conducting fabrics to sensors for detecting chemical agents.Ĭarbon nanotubes have enticed researchers since their discovery in 1991, offering an impressive combination of high strength, low weight, and excellent conductivity. Using an off-the-shelf inkjet printer, a team of scientists has developed a simple technique for printing patterns of carbon nanotubes on paper and plastic surfaces. Patent pending.Image: Electrically conductive image of Albert Einstein printed on copier paper with carbon nanotube ink. V2V is a trademark of Chasm Technologies, Inc. Demonstrated with functionalized and non-functionalized metallic and semi-conducting types Ĭompatibility with a variety of common substrates including polyester, polycarbonate and paper.īecause of the fluid properties, direct printing is possible – no need for masking ĭirect printing is safer than spray coating. Įasy to dry at relatively low temperatures (<100 ✬), with conventional ovens and dryers Ĭompatible with a wide range of CNT materials. Rheological properties that allow potential line speeds up to 300 ft/min. No residual viscosity modifiers, surfactants or dispersing aids to remove to achieve optimal performance. The new fluids have several key advantages over current state-of-the-art CNT fluids:ĬNT concentrations, up to at least 1 g/L, which allow single-pass printing operations or higher coverage per pass Figure 4 shows an SEM of screen-printed film showing the CNT structure.Įmploying a novel chemistry, CNT inks can now be printed using standard commercial printing equipment. Figure 3 shows screen-printed electrodes using the V2V CNT ink. Figure 2 is the ink being printed using commercial screen-printing equipment. Figure 1 is a representative curve of ink developed for a screen print application. Commercial applications such as LED lighting and touch pads/screens are being investigated. SWeNT CNT ink fluids have been successfully demonstrated on commercial screen printing equipment with relatively high CNT loadings (1 g/L). This is a straightforward process using the V2V technology, as the chemistries involved are compatible with a wide range of substrate materials. Coating the ink on polymeric materials may require changes to the viscous media formulation to minimize dilution and salvation effects of the ink fluid into the substrate layer. Changes to the viscous media component chemistry can also be altered to affect drying or substrate compatibility. The media viscosity can be easily adjusted to the desired range for the specific coating application through small chemistry changes. The V2V viscous media completely vaporizes at standard drying temperatures, leaving no significant traces of residual material that need to be removed in post processing or that affect the performance of the deposited CNT in the dried coating. ![]() The ability to print CNT inks in large areas, at high rates, with standard commercial printing equipment, will enable a wide range of printed electronics applications. These limitations have been significant barriers to commercialization of CNT inks for printed electronic applications. Ink jet printing has been successfully demonstrated for CNTs, but this technique is better suited for prototyping versus high-rate manufacturing. They also require an additional step of subtractive patterning via photolithographic etching or laser ablation. Traditional techniques that have been used to coat CNTs, such as spin coating and aerosol spraying, are not well suited for roll-to-roll coating. Most CNT inks do not have sufficiently high viscosity for commercial printing processes such as screen, flexo or gravure. These added steps increase cost and may not be compatible with other layers in the device. This requires an added rinsing operation and/or a high-temperature baking process. ![]() Oftentimes, non-volatile dispersants and surfactants are used, which must be removed in order for the optimal performance of the CNT to be realized. Most inks have very low CNT concentration, requiring multiple passes to achieve the desired CNT deposition, resulting in cost and resolution penalties.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |