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Polymers – from the Greek words for “many” or “much” and “part”, polus and meros – are large or macromolecules consisting of the same subunit repeating itself. In this way, quantum – meaning the smallest usable or possible part of something – polymers may be seen as something of a misnomer. However, in one area of quantum materials, quantum tunneling composites (QTCs), quantum polymers are being studied and applied today.
Properties of Quantum Polymers in QTCs
QTCs were discovered in 1996 by the technician David Lussey while he was searching for materials that could be used as electrically conductive adhesives (glues that conduct electricity). Lussey found that combining an elastomer – “a type of polymer that displays rubber-like elasticity” (Alemán et al., 2007) – with particles of metal, in this case, nickel, would produce a new composite material which could be used to uniquely exploit a feature of quantum mechanics, quantum tunneling.
Quantum tunneling is the effect of quantum mechanics where tiny, subatomic particles are able to pass through a potential barrier without using the potential energy that would otherwise be required of larger particles governed by the laws of classical mechanics. Put simply, a tiny particle at the quantum scale of size can go through walls without breaking them.
In QTCs, the combination of metal particles with elastomer leads to the formation of silicon spikes on the surface of the material’s molecules. These spikes move closer together when pressure or force is applied to the materials, which leads to a reduction in electrical resistance and therefore a higher electrical conductivity. In a quantum effect, electrons flow between the spikes to generate an electrical current.
Quantum tunneling is achieved in these compounded materials through careful selection of the precise shape of conductive nanoparticles like nickel, and a highly controlled process to combine them with other particles like an elastomer.
Through quantum tunneling, electrons also flow through the material and the current increases exponentially as pressure is applied. This means that, unlike classical electrical resistance which is linear or proportional to the distance that electrons travel, resistance in the polymer-metal combination of QTCs is reduced exponentially as pressure is increased.
QTCs are predominately manufactured in pill-form, however, QTC sheets comprising of a layer of QTC material, a layer of conductive material and a plastic insulating layer are also possible.
Applications of Quantum Polymers in QTCs
When he made his discovery, Lussey founded the company Peratech to continue research of QTCs and their applications. Peratech holds the intellectual property of both the formulations of QTCs and their materials manufacturing processes. In 2008, QIO Systems, a newly formed company, gained the exclusive worldwide license for the manufacture of ElekTek QTC-based textile touchpads, as well as the design and intellectual property of electronics and textiles that exploit the new QTC technology.
The majority of applications for quantum polymer-based QTCs have been in pressure and touch sensors which feature superior levels of control, reliability, and range over other kinds of sensors. This has led to uses in “smart” sporting materials and clothing which feature controls for electrical devices such as smartphones in membranes within the clothing textile. As well as uses for high-performance training, this technology also enables extreme conditions clothing as used in mountain or Arctic expeditions to combine with useful and even lifesaving technology in a way that would have been previously impossible.
Another application of QTCs in sporting goods is in fencing, where jackets or dummies can be covered in a QTC-based material to provide accurate, real-time information on touches to provide feedback on the force applied and accurate feedback on when hits are made.
Quantum polymer effects in QTCs are also applicable within the smart car industry, where car settings can be applied with a touch or gesture of the rear-view mirror or drivers’ side window.
QTCs can have applications in medicine as well. In blood pressure cuffs, QTCs can make more accurate blood pressure readings by reducing the risk of poorly attaching the cuff to the patient.
One notable application of quantum polymers in QTCs has been in space. In 2012, NASA launched the android Robonaut into space, where it used QTC materials in its fingertips to add a level of sensitivity to its inputs that would otherwise not have been possible. QTC technology-enabled Robonaut to know how hard it was gripping and where, and due to this it was able to survive its mission and return highly detailed feedback to NASA headquarters.
- Alemán, J.V., Chadwick, A.V., He, J., Hess, M., Horie, K., Jones, R.G., Kratochvíl, P., Meisel, I., Mita, I., Moad, G., Penczek, S. and Stepto, R.F.T. (2007). Definitions of terms relating to the structure and processing of sols, gels, networks, and inorganic-organic hybrid materials (IUPAC Recommendations 2007). Pure and Applied Chemistry, 79(10), pp.1801–1829.
- Peratech (2016). Peratech - What is QTC? Peratech.com. [online] Available at: https://www.peratech.com/what-is-qtc.html [Accessed 14 Sep. 2019].