An Introduction to Nanotechnology by Ignition Technology Consulting

About the Authors Ignition Technology Consulting provides technical advice, services and solutions to promote commercial success. Our science and engineering skills are used by multinational companies, startups and investment firms in the pursuit of improved growth, profit and returns. This guide is part of our Technical Intelligence series. Further information can be provided on request: intell@ignitiontechnologyconsulting.com www.ignitiontechnologyconsulting.com

Getting Started in Nanotechnology Nanotechnology has been a technology buzzword for the last decade: Its revolutionary potential is enormous, yet the range of technologies and applications that are classed as nano can make it hard for the nonexpert to get an understanding of what nanotechnology is and how it could benefit them. Read on for a beginner’s guide to nanotechnology:

What is Nanotechnology?

Why now?

Nanotechnology is the catchall term for technical solutions that rely on structures that are below 100 nanometers in size and the special phenomena that arise at this scale. It also encompasses technology for imaging, measuring, modelling and manipulating matter at this scale.

Nanotechnology has risen to prominence over the last 30 years on the back of significant developments in microscopy which have enabled scientists and technologists to observe and manipulate things at the nanoscale.

Why is it so exciting? Nanomaterials and structures exhibit very different characteristics to larger things and have unusual properties and functionality as a result. Two phenomena are responsible for these unusual properties: • The isolation of quantum effects resulting in changes to optical, magnetic and electrical properties. • The presence of disproportionately large surface areas resulting in greater chemical reactivity and changes to strength, electrical and thermal properties. Consequently metals can be made transparent, stable materials become catalytic, materials can become superstrong and insulators can become superconductive (to give just a few examples).

Jargon Buster Nano Nano refers to the nanometre scale. There are 1 billion nanometres (nm) in a metre, and the average human hair is about 100,000 nm wide. A good way of conceptualising this scale is provided by the US Government’s National Nanotechnology Initiative.

Graphene

Carbon Nano-Tubes (CNTs)

Graphene is a twodimensional material (only one atom thick) which was first isolated in a lab in 2004. It is over 200 times stronger than steel, ultra heat and electrically conductive, virtually transparent, flexible and only permeable to water. These properties mean it could be integral to a huge variety of revolutionary applications.

Carbon NanoTubes are tubular carbonallotrope based materials (in fact made from rolled graphene) where the diameter of the tubes is nanoscale. They were first identified in 1991. They can be single walled or multiwalled tubes with varying length scales. They are extremely strong, highly electrically conductive (being either metallic or a semiconductor) and are very flexible. They also have unique chemical properties which can be tuned according to use.

Graphene was the first 2Dcrystalline structure identified, but various others have been proposed by researchers (e.g. silicone, germanene, stanene, and phosphorene) which may also have various superproperties which would be of particular interest because they could behave as semiconductors.

CNTs are already available in bulk quantities, although it is still not possible to manufacture tubes of a highly consistent size which limits their application. Various other inorganic nanotubes have also been identified which have different enhanced properties.

Nano-particles

Quantum (or nano-) dots

Nanoparticles are generally defined as being particles less than 100nm in diameter and they exhibit different properties to larger particles of the same material. By mixing nanoparticles into other conventional bulk materials, new improved properties can be conferred upon the bulk material. In this way nanoparticulates are already in quite widespread use in various applications.

A quantum dot (or nanodot) is a crystal particle of a semiconductor material generally only a few nanometers in diameter which owing to its tiny scale is strongly influenced by quantum effects determining its electrical and optical properties. These properties could make them useful for screen, imaging and anticounterfeiting technologies. Nanodots and nanoparticles can assemble into socalled nanowires which can also confer special properties to materials.

When will nanotechnology change the world? Some nanotechnology applications and products have been on the market for some time but the truly revolutionary stuff is still in the future. Some people predict that nanomaterials such as graphene will unleash a new industrial revolution, but with many challenges still to overcome before these technologies become mainstream this revolution is still a long way off.

First wave Existing products and applications usually rely on nanocomposites and are first wave nanotechnology. By mixing nanoparticles into conventional bulk materials (such as polymers or metals) it is possible to dramatically change the bulk material’s properties. Sometimes these materials are used as thin coatings. For example titanium dioxide nanoparticles are routinely put into sunscreen emulsions to provide a transparent UV barrier. Other widely used nanoparticulates include nanoclays, metals such as gold and silver as well as the slightly less widely used quantum dots and Carbon NanoTubes (CNTs). A handful of products have also been launched which use graphene based particles. More first wave products are likely to emerge when the quality of nanoparticles (which act as fillers) can be made more consistently and at a much lower cost than today.

Second wave The next generation of nanotechnology applications will see more revolutionary functionality which will rely on components made directly from nanomaterials (rather than mixing nanoparticulates or nanotubes into bulk materials). For example these applications might use sheets of graphene (perhaps bound within other laminate materials) or organised Carbon NanoTubes bound to a surface or woven into a yarn or sheet. These components will offer new enhanced properties and revolutionary applications.

CNTs might be designed to give them specific functionality. For example, other functionalised molecules (such as drugs) could be encapsulated within or bonded to the tubes and delivered to highly targeted sites. Scientists are also predicting the existence of 2dimensional materials other than graphene. These alternative materials are currently being researched and include for example; silicone; germanene; stanene and phosphorene. If it is possible to manufacture these materials consistently and cost effectively they might unlock more revolutionary applications. There are many second wave applications being researched in laboratories around the world, but as yet no commercially available second wave products. Before second wave products can truly breakthrough, bulk production processes will need to improve, manufacturing supply chains will need to develop capabilities to handle and manipulate the new materials and costs will need to align with market requirements. Significant research and development efforts are being made to address all these challenges. The proliferation of second wave products and applications could be the start of the forecast nanotechnology industrial revolution. Based on current progress it seems likely that this is at least 10 years away.

Third wave In the future, a third generation of nanotechnology is forecast which will emerge based on highly controlled manipulation of materials at the nanoscale. In this scenario devices might be designed from molecular scale building blocks creating nanoscale devices. This may be considered an evolution of the emergence of MEMs (MicroElectromechanical systems) which are miniaturised devices that feature tiny sensors, valves, gears and actuators integrated into single computer chips. The new devices will be known as NEMs (NanoElectromechanical systems). More complex devices are sometimes conceptualised as nanorobots which might be used in all manner of ways. In a more futuristic scenario components of or even whole devices might be capable of selfassembly. This possibility is currently known as Molecular Manufacturing and is a growing field of research alongside molecular electronics.

Applications The list of potential applications is infinitely long as nanotechnology super materials might eventually be incorporated into virtually any object or product. Below we identify some of the existing applications of nanotechnology and show some of the more exciting potential applications expected to appear in the future.

Personal Care Nanoparticles of Titanium Dioxide are regularly used in sunscreen to provide transparent UV protection.

Silver nanoparticles are being used in soaps, lipsticks and other beauty products to provide antibacterial properties.

Toothpastes are on sale in various countries containing a variety of nanoparticles which confer antibacterial, whitening and sensitivity reduction benefits.

Moisturisers boasting liposomes are effectively benefiting from nanoingredients. They are usually used to encapsulate moisture and to penetrate deeper within skin tissue. Nanogold is reportedly being used in moisturisers for its alleged antioxidant and healing properties.

Household Care

Various antibacterial cleaning products are emerging which contain nanoparticles.

Various surface coatings containing nanoparticulates and CNTs give products water repellancy and selfcleaning properties.

Food & Nutrition Antimicrobial coatings featuring silver nanoparticles are already in use on food contact surfaces such as chopping boards.

Nanoadditives are already being used in various products to improve emulsification and as flavour enhancers.

Nanoparticles are starting to be used in various plastic food packaging materials to extend product life by improving barrier and antimicrobial properties. In future, simple low cost nanosensors will be used to monitor exposure conditions (temperature and humidity) and detect when food is rotten. In future nanoingredients might provide healthy replacements to traditional ingredients.

Researchers propose that in future nanoencapsulation of nutrients and additives might improve biological takeup within the body.

Advanced Materials

Nanocomposites (based on particles and fibres) are already being used to coat materials to give them water or dirtrepellancy and flame or chemical retardency and antibacterial properties. In the future more sophisticated materials should facilitate other smart fabrics.

Ultrastrong, lightweight components made from nanocomposites are already appearing in vehicles and aircraft (in polymers, steels and glass) and as second wave materials become commercially viable, we can expect to see more and more components made from nanomaterials.

Environmental Protection Low energy water purification: Various nanocomposites and nanomaterials make particularly effective water purification membranes (e.g. graphene is only permeable to water) suggesting there will be many novel water purification technologies and new desalination systems.

The same types of devices could also be used for air purification and pollution capture.

Functionalised nanoparticles and materials can be tuned to attract specific compounds and might be used for environmental remediation for example mopping up oil and other pollutant spills.

Various nanomaterials might be used to capture carbon and pollution.

Themoelectric nanomaterials might faciliate waste heat regeneration in industrial processes.

Buildings & Construction Nanoparticulates are already widely used in paints and surface coatings to provide selfcleaning and biocidal properties. As costs come down, and more sophisticated nanomaterials become commercially viable more widespread use in construction materials is expected for improved strength, crack resistance, and durability and to confer selfhealing and insulation properties. It should also be possible to reduce the amount of raw material required for a given application and reduce energy required for production.

Energy Systems Researchers have demonstrated that various nanomaterials (e.g. CNTs, nanodots and graphene) could improve the performance of solar cells in a variety of ways. For example by improved electrode conductivity, transparent electrode designs in polymer cells, trapping more sunlight and as photoelectric materials. CNTs are already being used on a limited scale to enable faster charging and improved battery life. It is forecast that using nanomaterials and composites in batteries could deliver breathroughs in size, weight and performance to enable the widescale take up of electric cars and dramatically improve battery performance in general. Nanomaterials could be used to make fuel cells more viable by improving electrode and membrane performance, making containing walls more gastight, storing hydrogen and improving catalysts used for fuel production.

CNTs are already being used to increase the energy storage capacity of capacitors. Further improvements are predicted as nanomaterials mature.

Electronics Nanomaterials are expected to be widely used in screen technology. CNTs are already being used within ultrathin, low power OLED displays, but a whole new class of displays known as Field Emission Displays could be the future for large area, high definition, low cost screens. They capitalise on the photoluminescent properties of CNTs. Nanomaterials could also replace INT currently used as the transparent electrodes for touch screens. Nanoparticulates are already used to reduce the size and improve the performance of various computer chips and components. In future a variety of nanomaterials will yield yet more improvements facilitating extremely small, high power devices.

Nanowires and materials are being demonstrated as part of thin, flexible electronic components.

Anti-Counterfeit Solutions

Nanoscale barcodes can be printed on bank notes (and other items) to create a covert authentication mark.

Nano fingerprinting is already possible by creating unique markers using nanoparticulate based coatings.

Individual RFID tags have nanoscale variations which could be detected and identified during data reading tasks.

Laser surface authentication allows objects/materials to be recognised by scanning their unique nanosurface structures.

Sensors

Various nanomaterials change their properties in the presence of very small quantities of other molecules. This, combined with nanoinnovation in electronics, should lead to a profusion of small, lowcost, ultrasensitive sensors tuned to detect all manner of different substances.

Medical Technology

In the future, specialised drugs could be encapsulated or attached to nanocarriers which are designed to travel to specifically targeted cells and are unloaded by a controlled trigger.

Nanosctructured scaffolds show promise for better and faster bone and tissue regeneration.

Extremely small and highly sensitive sensors based on many different functionalised nanoparticles could be tuned to respond to the presence of specific biomolecules as part of smallscale diagnostic devices used in surgeries or even within the body.

High resolution imaging should be possible by deploying highly targeted nanocompounds to act as tracers within the body.

Nano-robots (NEMS) Much further in the future, ultra small robotic devices which might selfassemble or be made from ultra small components could be used in a huge variety of ways which would need to be carefully controlled from an ethical standpoint. For example, invivo medical robots might be a good thing but similar robots deployed as part of biological warfare could be extremely problematic.

Barriers to adoption of nanotechnology At the current time the major barriers to uptake of nanotechnology are an absence of manufacturing capability and prohibitively high costs. Some nanomaterials such as Carbon NanoTubes are available in bulk already, but they remain expensive and more research and development is required to develop capabilities for manufacturingscale manipulation to make the most of their potential in realworld products. Furthermore, manufacturers still find it difficult to control the quality of CNTs which also restricts their application. Meanwhile no costeffective industrial scale graphene production method has yet been implemented. A further barrier is the safety risks inherent in handling the materials. This could further limit the emergence of nanoapplications and products. The mobility and reactivity of nanomaterials means their free release into the environment or people’s bodies can be extremely hazardous. Regulations and protocols to mitigate these risks will be needed.

Further reading Here are a few websites which provide easily accessible further reading: http://www.nano.gov http://www.nanowerk.com http://www.understandingnano.com/introduction.html More in depth information from these publications: http://www.azonano.com ACS Nano (journal) Journal of Nanoscience and Nanotechnology (journal) Nanotechnology (journal) Nano Letters (journal)

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