Microscopic Robots may help Printing Industry

Manipulating matter at an atomic level opens up print to new possibilities

The print industry has long benefitted from the application of clever minds to fundamental material science. Understanding the chemistry and fluid mechanics of ink has enabled high-speed printing onto lightweight papers and novel substrates. Developments will broaden the range of materials that can be printed, extending the range of printed products. One of the technology wildcards is the adoption of nanotechnology, manipulating material at the scale of individual atoms and molecules. According to the US National Science Foundation, nano-engineering applications will become a $1 trillion market within 20 years, and this has implications for the print sector.

Research covers a range of interesting potential applications. Printing techniques are being explored to produce quantum dots in specialised inks, anti-counterfeiting, pigments and infrared paints, and tag and trace applications. German company Nanosolutions has developed Ren-X, a solution incorporating nanosized particles of rare earth elements lanthanum and yttrium. This is added to inkjet ink to print documents that are invisible to the naked eye but show a distinct signature under UV light, hence validating the document. TAL Materials of Ann Arbor, Michigan, has launched upconverting (UP) phosphor nanopowders for a number of security and authentication applications. These emit visible light when exposed to infrared light, a phenomenon not occurring in nature, again useful for authentication.

Security information
Intelligent packaging could provide information on pack contents, such as whether it has gone bad. Developers are discussing self-cleaning labels and packaging. Better anti-static properties collect less dust on packs and better surface finish with less shrinkage. There may be novel decoration techniques and improved feel (haptic properties) for consumers. Nanoparticles may offer better UV protection in thinner films with less environmental impact than current sun-block materials. Novel optical properties might include the ability to refract light so the paper changes colour depending on the light source.

Currently pigments and inks are probably the most advanced commercial print application for nanotechnology, but the paper and board industry has well-established applications for nanotechnology, both in new products and improving papermaking. Nanoparticles can be incorporated in the coating of papers to improve optical characteristics and printability by improving ink fixing at high densities and control colour bleeding more effectively. Alternative nanoparticles are used in drainage and retention systems for wet-end chemistry, while nanofiltration technology can be used to filter effluents and make the whole process more eco-friendly.

As well as new materials, nanotechnology may involve self-assembly systems from the bottom up on a molecular scale. Researchers at the University of Illinois have devised a new type of quick-setting 3D ink that works a bit like a microscopic tube of toothpaste. A printer robotically deposits a continuous, elastic-like ink filament into a liquid rather than putting ink drops onto a surface. The process yields complete 3D structures at resolutions that are two orders of magnitude finer than existing methods.

Supporters of nanotechnology make very bold and unlikely claims of the potential, with biotechnology involving micro-machines wandering around bodies, fixing damage and extending lives. Mastery of the technology may allow manipulation of matter at the atomic level. Complete products may be prepared from chemicals recreating the processes normally done in living organisms. Complex devices could be grown by dumping materials and instructions and allowing assembler microbots to get on with it.

There are serious technical obstacles that will impede this vision. Cell-like processes will likely take place at cell-like speeds, far too slow for most manufacturing but the potential exists. It is unlikely we would ever grow a printed product (don't throw your Speedmaster away just yet), but we may well use the technology to develop alternative communication products.

30-second briefing on... Nanotechnology
- Nanotechnology results from the properties exhibited by specialist molecules, nanomachines and nanoparticles, ranging in size between 100nm down to the atomic scale, around 0.2nm. While you read this sentence your nails will grow by more than 1nm. A human hair is some 80µ wide, two thousand times the nanotechnology size range and one of your red blood cells is 200 times larger

- At this scale many materials display characteristics based on quantum mechanical forces that are exhibited at the level. Materials may become more conductive, transfering heat better or have modified mechanical properties

- For printing, adding such materials to inks can provide novel security properties. Current commercialised print applications include specialist security and electronic inks, with paper and substrate manufacturers providing interesting surface properties through the use of nanotechnology

- Paper manufacturers are examining materials to improve the papermaking process and to provide novel properties

- Nanotechnology is the projected ability to make things from the bottom up, using techniques and tools that are being developed today to place every atom and molecule in a desired place

- This molecular engineering involves specialist manufacturing techniques, including printing. The emerging nanoprinting technology may produce bio-medical and electronic devices, possibly the next generations of integrated circuits and computers.

Sean Smyth, 15/03/2007