Basics of Nanomaterials & its overview

Introduction to Nanomaterials

Nanomaterials are foundations of nanoscience and nanotechnology. Nanostructure science and innovation is a wide and interdisciplinary region of innovative work movement that has been becoming attractive around the globe in the previous couple of years. It has the potential for reforming the routes in which materials and items are made and the range and nature of functionalities that can be gotten to. It is as of now having a noteworthy business affect, which will without a doubt increment later on.

Gradual development of science and technology and the future

Nanoscale materials are characterized as an arrangement of substances where no less than one measurement is not as much as around 100 nanometers. A nanometer is one millionth of a millimeter - around 100,000 times littler than the distance across of a human hair. Nanomaterials are of intrigue on the grounds that at this scale one of a kind optical, attractive, electrical, and different properties develop. These new properties have the potential for extraordinary effects in gadgets, prescription, and different fields.

Some nanomaterials happen normally, yet exceptionally compelling are built nanomaterials, which are intended for, and as of now being utilized as a part of numerous business items and procedures. They can be found in such things as sunscreens, beautifying agents, donning merchandise, recolor safe garments, tires, hardware, and in addition numerous other regular things, and are utilized as a part of solution for motivations behind conclusion, imaging and medication conveyance. 

Built nanomaterials are assets outlined at the sub-atomic (nanometre)level to exploit their little size and novel properties which are by and large not found in their regular, mass partners. The two fundamental reasons why materials at the 

nano scale can have distinctive properties are expanded relative surface range and new quantum impacts. Nanomaterials have a considerably more prominent surface range to volume proportion than their traditional structures, which can prompt more noteworthy synthetic reactivity and influence their quality. Likewise at the nano scale, quantum impacts can turn out to be substantially more essential in deciding the materials properties and qualities, prompting novel optical, electrical and attractive practices.

Nanomaterials are now in business use, with some having been accessible for quite a while or decades. The scope of business items accessible today is exceptionally expansive, including stain-safe and sans wrinkle materials, beautifying agents, sunscreens, gadgets, paints and varnishes. Nanocoatings and nanocomposites are discovering utilizes as a part of different purchaser items, for example, windows, sports gear, bikes and cars. There are novel UV-blocking coatings on glass bottles which shield refreshments from harm by daylight, and longer-enduring tennis balls utilizing butylrubber/ 

nano-mud composites. Nanoscale titanium dioxide, for example, is discovering applications in beautifiers, sun-piece creams and self-cleaning windows, and nanoscale silica is being utilized as filler in a scope of items, including beauty care products and dental fillings.

Are they new?

In some senses, nanoscience and nanotechnologies are not new. Chemists have been making polymers, which are large molecules made up of nanoscale subunits, for many decades and nanotechnologies have been used to create the tiny features on computer chips for the past 20 years. However, advances in the tools that now allow atoms and molecules to be examined and probed with great precision have enabled the expansion and development of nanoscience and nanotechnologies.

The bulk properties of materials often change dramatically with nano ingredients. Composites made from particles of nano-size ceramics or metals smaller than 100 nanometers can suddenly become much stronger than predicted by existing materials-science models.

For example, metals with a so-called grain size of around 10 nanometers are as much as seven times harder and tougher than their ordinary counterparts with grain sizes in the hundreds of nanometers. The causes of these drastic changes stem from the weird world of quantum physics. The bulk properties of any material are merely the average of all the quantum forces affecting all the atoms. As you make things smaller and smaller, you eventually reach a point where the averaging no longer works.

Nanomaterials can

       - occur naturally

       -  be produced by human activity either as a product of another activity 

       - on purpose (engineered)

       - our focus: engineered nanomaterials as these are designed and integrated into products because of the specific characteristics of the nanomaterial  

Fundamental triangle of materials science.

The properties of materials can be different at the nanoscale for two main reasons:

1.         Nanomaterials have a relatively larger surface area when compared to the same mass of material produced in a larger form. This can make materials more chemically reactive (in some cases materials that are inert in their larger form are reactive when produced in their nanoscale form), and affect their strength or electrical properties.

2.         Quantum effects can begin to dominate the behaviour of matter at the nanoscale - particularly at the lower end - affecting the optical, electrical and magnetic behaviour of materials. Materials can be produced that are nanoscale in one dimension (for example, very thin surface coatings), in two dimensions (for example, nanowires and nanotubes) or in all three dimensions (for example, nanoparticles).

Classification of nano – materials: (a) three – dimensional structures; (b) two – dimensional; (c) one – dimensional; and (d) zero – dimensional structures.

Approaches of Nanotechnology (growth methods)

           •Bottom-up, or self-assembly, approaches to nanofabrication use chemical or physical forces operating at the nanoscale to assemble basic units into larger structures, while top-down approaches seek to create nanoscale devices by using larger, externally controlled ones to direct their assembly.

    •The top-down approach often uses the traditional workshop or microfabrication methods where externally controlled tools are used to cut, mill, and shape materials into the desired shape and order.

Applications of Nanotechnology

Today, a life without nanotechnology is hard to imagine. Nanotechnologies – to be more specific: nanomaterials – are already used in numerous products and industrial applications. Nanotechnology Products and Applications database already provides an overview of how nanomaterials and nanostructuring applications are used today in industrial and commercial appplications across industries 

This provides you an excellent  overview of what nanotechnologies are, what they are used for, and what some of the key issues are. 

Here is a brief overview of some current applications of nanomaterials. Most of them represent evolutionary developments of existing technologies: for example, the reduction in size of electronics devices. 

General Applications

Medicine

Information and communication

Heavy Industry

Consumer goods

Environmental Applications

Carbon capture

Sensors

Remediation (decontamination, oil spill management)

Wastewater treatment

Energy

Drinking water purification 

Nanocomposites

An important use of nanoparticles and nanotubes is in composites, materials that combine one or more separate components and which are designed to exhibit overall the best properties of each component. This multi-functionality applies not only to mechanical properties, but extends to optical, electrical and magnetic ones. Currently, carbon fibres and bundles of multi-walled CNTs are used in polymers to control or enhance conductivity, with applications such as antistatic packaging. The use of individual CNTs in composites is a potential long-term application. A particular type of nanocomposite is where nanoparticles act as fillers in a matrix; for example, carbon black used as a filler to reinforce car tyres. However, particles of carbon black can range from tens to hundreds of nanometres in size, so not all carbon black falls within our definition of nanoparticles.

Nanoclays

Clays containing naturally occurring nanoparticles have long been important as construction materials and are undergoing continuous improvement. Clay particle based composites – containing plastics and nano-sized flakes of clay – are also finding applications such as use in car bumpers.

Tougher and Harder Cutting Tools

Cutting tools made of nanocrystalline materials, such as tungsten carbide, tantalum carbide and titanium carbide, are more wear and erosion-resistant, and last longer than their conventional (large-grained) counterparts. They are finding applications in the drills used to bore holes in circuit boards.

Nanopaints

Incorporating nanoparticles in paints could improve their performance, for example by making them lighter and giving them different properties. Thinner paint coatings (‘lightweighting’), used for example on aircraft, would reduce their weight, which could be beneficial to the environment. However, the whole life cycle of the aircraft needs to be considered before overall benefits can be claimed. It may also be possible to substantially reduce solvent content of paints, with resulting environmental benefits. New types of foulingresistant marine paint could be developed and are urgently needed as alternatives to tributyl tin (TBT), now that the ecological impacts of TBT have been recognised. Anti-fouling surface treatment is also valuable in process applications such as heat exchange, where it could lead to energy savings. If they can be produced at sufficiently low cost, fouling-resistant coatings could be used in routine duties such as piping for domestic and industrial water systems. It remains speculation whether very effective anti-fouling coatings could reduce the use of biocides, including chlorine. Other novel, and more long-term, applications for nanoparticles might lie in paints that change colour in response to change in temperature or chemical environment, or paints that have reduced infra-red absorptivity and so reduce heat loss.

Concerns about the health and environmental impacts of nanoparticles may require the need for the durability and abrasion behaviour of nano-engineered paints and coatings to be addressed, so that abrasion products take the form of coarse or microscopic agglomerates rather than individual nanoparticles.

Nanolubricants

Nanospheres of inorganic materials could be used as lubricants, in essence by acting as nanosized ‘ball bearings’. The controlled shape is claimed to make them more durable than conventional solid lubricants and wear additives. Whether the increased financial and resource cost of producing them is offset by the longer service life of lubricants and parts remains to be investigated. It is also claimed that these nanoparticles reduce friction between metal surfaces, particularly at high normal loads. If so, they should find their first applications in high-performance engines and drivers; this could include the energy sector as well as transport. There is a further claim that this type of lubricant is effective even if the metal surfaces are not highly smooth. Again, the benefits of reduced cost and resource input for machining must be compared against production of nanolubricants. In all these applications, the particles would be dispersed in a conventional liquid lubricant; design of the lubricant system must therefore include measures to contain and manage waste.

An excellent staring point is this chart that lists an impressive collection of applications of nanoparticles

Application of nanoparticles - Chart

Nanomaterials design

In nanomaterials science, the development of new materials drives many fields of engineering; i.e. alloys with improved mechanical properties and reduced weight, 

eg: To increase  stiffness and at the same time save weight in aerospace or automotive industries.

Composite materials follow the same trend, many of them mimicking the structure of biological tissues like wood, bone, shell, spider silk and many more examples.

The use of such new nanomaterials will be essential to address major future global demands such as reducing energy consumption or the ecological impact of almost any product we use.

Structural nanomaterials

These materials based on metallic, ceramic and polymer systems will provide a step change in mechanical and thermal properties. They will be the basis for a wide range of innovations and new applications exploiting nanoscale effects.

Functional or 'smart' materials

        They will drive forward developments in electronic, photonic, structural and magnetic devices. Nanomaterials will raise the development to a new level, employing novel physical, electrical and mechanical effects to make electronics which will be faster, lighter, cheaper, and easier to manufacture, and which will have low power consumption.

        Simple devices based on nanomaterials will deliver functions which would ordinarily require a more complex mechanism or component, such as the replacement of electrical connections by optical links and improved non-volatile computer memory. Designing materials operation in stringent environments (temperature, pressure, radiation etc.) is also needed.

Polymer nanomaterials

     They will advance dramatically as the chemical and nanoscale structures of polymers are engineered to create new polymers with a multitude of structural and functional applications, ranging from polymers with improved biodegradability to new adhesives and novel electrical conductors. Biopolymers for the life sciences will use the principles of hierarchical assembly in living organisms and apply them to engineered materials and structures.

Nanostructured coatings, composites and hybrids

        These can be engineered to exploit a revolutionary combination of tailored properties, between coating and substrate, between composite matrix and reinforcement, and between the different components of a hybrid.

Size Dependent Properties of Nanomaterials 

         The various properties, which get tremendously altered due to the size reduction in at least one dimension are:

a) Chemical properties: Reactivity; Catalysis.

b) Thermal property: Melting point temperature.

c) Electronic properties: Electrical conduction.

d) Optical properties: Absorption and scattering of light.

e) Magnetic properties: Magnetization.