Nano and Micro Materials for A Sustainable Green World: Nano Cellulose Example

Nano and Micro Materials for A Sustainable Green World: Nano Cellulose Example

Nanomaterials are those materials which are present on a nanometric scale which means it is below nm in either one of its dimension. They are known as nanomaterials because of the size that they hold which is equal to the size of a grain and has a very high fraction as well. The natural production of nanomaterials is done by many geological, cosmological, meteorological, and biological processes. Green Nanotechnology is for supporting sustainability by using the green nanoproducts that they make and by doing things right in the first place. The matter is manipulated, measured, imaged, and modeled at this length scale with the involvement of nanotechnology, nanoscale engineering, science, and technology is also encompassed. For minimizing potential risks to the environment, green technology is developed for developing clean technologies. The process of manufacturing and nanotechnology product usage is associated with it. For developing new nanoproducts, existing products are substituted and are encouraged by the green nanotechnology to do so. They are friendly to the environment because of the synthesis of new nanoproducts, which have friendly nature throughout their lifetime.

Table of Contents

Introduction

Nanostructured materials:

Properties:

Nano and micro materials for a sustainable green world:

Aim of Green Nanotechnology:

Nanomaterials and their role to prevent pollution

Background

Properties

Applications

Role in preventing pollution

Twelve Principles of Green Chemistry:

Nano-cellulose as a plastic alternative

Production

Properties

Applications

The protective layer on Cardboard

Manufacturing of new friendly environmental materials

Packaging and Paper Industry

Food packaging

Replacing plastic in packaging materials of future

How Could Cellulose Nanomaterials Improve Capacity for Renewable Energy Storage?

What are Cellulose Nanomaterials?

Cellulose nanomaterials and renewable energy storage

How nanocellulose can improve the energy storage capacity of devices

Nanocellulose-based composites for supercapacitors

Supercapacitors

Electrodes

Aerogels

3D-Supercapacitors

Ultrathin energy storage

Flow batteries

Nanocellulose in energy conversion devices

Conclusion

References

Nanografi's Nanocellulose

Introduction

Nanomaterials are those materials which are present on a nanometric scale which means it is below nm in either one of its dimension. The physical properties which the nanomaterials show are uniformity, conductivity, or the optical properties which makes these nanoparticles very much desirable in the fields of science and biology. Nanomaterials are so small that they cannot be seen an ordinary microscope and instead an electron microscope is used to view these materials. These materials occur at a great scale in nature and are often attracted to study in various fields of science such as biology, geology, physics, and chemistry. They are present at transition in between the bulk materials and atomic or molecular structures and because of this, they show a phenomenon that is not observed at any of the scales.

Nanomaterials play a great deal of role in atmospheric pollution and are happened to be a much-needed ingredient in some of the industrial products, for instance, paints, ceramics, metals, magnetic particles, and plastics. Nanomaterials can be naturally produced by many biological, cosmological, geological. And meteorological processes. At thousands of tons per year rate, a remarkable fraction not by the interplanetary dust’s mass but by number is still falling on the Earth in the nanomaterial range and it is the same for the atmospheric dust particles.

Nanostructured materials

Nanoparticle Products

The nanostructured materials which are 1–100 nm in size are very well known for showcasing excellent mechanical and physical properties. It is because of the size that they hold which is equal to the size of a grain and has a very high fraction as well. According to recent searches, a very progressive amendment has been made in different scenarios to synthesize the nano-scale materials. Initially, all the researchers were merely focused on the synthesis of nanomaterials but now they are more focused on synthesizing the nanomaterials to produce useful structures from them, and because coatings having greater wear and corrosion resistance so it is very useful in this field.

Properties

The nanomaterials possess a variety of remarkable chemical and physical properties. The categories of chemical properties, are electronic and optical and are present in the form of bulks and are very distinctive of each other. When the materials are present in nano size, their properties are hard to identify as compared to the times when they are present in the larger size. This includes both the chemical and physical properties. The properties of these materials may change when in the presence of certain chemical combinations. The basic characteristics of these materials are that they possess a definite shape with approximate fixed size, possess the surface characteristics, and also have an inner structure. The physical properties which the nanomaterials show are uniformity, conductivity, or the optical properties which makes these nanoparticles very much desirable in the fields of science and biology. Nanomaterials are also confronted as emulsions (liquids in liquids), as suspensions (solids in liquids), and as the aerosols (liquids or solids in the air).

Nano and micro materials for a sustainable green world

“Green Nanotechnology is about doing things right in the first place & about making green nano-products and using nanoproducts in support of sustainability". The matter is manipulated, measured, imaged, and modeled at this length scale with the involvement of nanotechnology, nanoscale engineering, science, and technology is also encompassed. The bulk matter has individual molecules and atoms, their characteristics are different from the chemical, biological, and physical characteristics of materials in valuable and fundamental ways. These characteristics are exploited by the enhanced devices, systems, and materials that are created and understood by Nanotechnology R&D. They lead to clean manufacturing methods, lighter and stronger building materials, computers that are of small size but fast, and more strong ways of treating disease after detecting it.

Nanocellulose: Descriptions, Usage and Applications

A sustainable and exciting future is promised by nanotechnology. Many researchers used nano clay and nanoparticles as the additives in polymer nanocomposites. For minimizing potential risks to the environment, green technology is developed which develops clean technologies and itself is a technology. The process of manufacturing and nanotechnology product usage is associated with it. For developing new nanoproducts, existing products are substituted and are encouraged by the green nanotechnology to do so. It's a friendly environment due to the new nanoproducts synthesis.

Technology means the knowledge application for real-life purposes. The green nanotechnology field encompasses a continuously growing material group of materials and methods, from the techniques for the generation of energy to non-toxic cleaning products. It's not possible to guess what is encompassed by the green nanotechnology in the early stages. Commercialization and innovation aren't stalled by the product safety design if a wider focus is given on determining the rules of design which also permits protection to nanomaterials from the outset. Throughout the life cycle of the material, especially the phase of production, hazards are not addressed. Such an approach is green nanoscience which has the purpose of creating and applying the design rules proactively for greener nanomaterials and for developing synthetic strategies that are efficient to produce nanomaterials reproducibly with defined purity, structure, and composition.

The well known green chemistry 12 principles are applied but the green nanoscience for the production of design, and nanomaterials usage. For removing and lessening dangers to human health and the environment, green nanoscience like green chemistry is used through optimization of the process and product design. Recently, these 12 principles of green chemistry are described and their applications in nanoscience.

Knowledge tools (eco/bio testing procedures, characterization tools, synthetic methods, characterization strategies, and mechanistic understanding) and base needs to be developed if we want to lessen those principles to practice in order to act quickly for finding material replacements for the materials which are not safe enough, for designing novel materials, and for producing well-defined materials efficiently and reliably. Analysis tools are also needed for complementing these strategies because they help in the processes of decision making about weighing in the competing technologies' merits.

Aim of Green Nanotechnology

Green nanotechnology has an ultimate purpose, creating technologies, allowing nano-pigments production in more environmentally friendly ways by using the raw materials, which in contrast with production technologies nowadays are more majorly sustainable. For achieving such purpose, the green nanotechnology must intend on achieving the following points:

• Nano-pigments preparation based on the usage of selected natural, and nano-clays, and synthetic dyes

• For nano-clays for enhanced dye molecule’s fixation, Surface treatment technologies

• In photovoltaic devices, green nanoparticles applicability

• Surface treatment technologies for colored nano-clays for enhanced light-fastness, dispersibility, fatigue cycle, and weather-resistance

• Greener Nanopigment’s applicability in coatings, printing inks, and paints

• Evaluation of the Greener nano pigments environmental impacts

• Greener Nanopigment’s dissemination and commercial exploitation. Green Nanotechnology, green chemistry, and green engineering are inter-related terms. Enhancing the properties of one will automatically improvise the other two. Without green chemistry, one cannot think of achieving the goals of green nanotechnology.

What is Green Graphene?

Nanomaterials and their role to prevent pollution

The nanomaterials include the particles which at least have one of their dimensions in the nanoscale. These are obtained through three main sources which include; naturally occurring, production as a byproduct of other processes, and the industrially engineered. As the technology is relatively new, a lot of research and experiments are going on it to get the idea of the potential this technology withholds. It has found roles in cosmetic, sports, electrical, and healthcare industries. One of the most important prospects of nanomaterials is in the field of pollution prevention and control. It can be used to control air pollution, water pollution, and land pollution. In short, the future of this technology looks very bright, and the nanomaterials have been proved very efficient in the removal of pollution.

Graphene Products

Nanomaterials are the materials whose structure is composed at a nanoscale, or its constituents have the dimensions of the nanoscale. The nanoscale usually refers to the materials ranging from the dimensions of the 1 nm to 100 nm. They have unique properties due to their nanostructure and the nano composition. The sources of nanomaterials are mainly the three. First is by engineering where humans synthesize the nanomaterials according to their need having certain properties required for that task. The examples include carbon black and titanium dioxide nanoparticles. Secondly, they are also produced as a side product of other industrial and mechanical processes. The examples include the exhaust of the car engines, fumes from welding, burning of the solid fuels in homes to cook food or heat the homes, etc. The third source is nature itself. Many of the plants and fungi have a structure consisting of the nanomaterials. One of the best examples of the perfect nanomaterial structure is the structure of a virus. Both organic and inorganic nanomaterials are available in our environment naturally.

Reduced Graphene Oxide (rGO), S.A: 1562 m2/g, 2-5 layers  Graphene Oxide, 2-5 Layer, Dia: 7,5 µm, SA: 420 m2/gr

The engineered nanomaterials are also being commercially available with a variety of applications. A class of nanomaterials, also known as fullerenes, are produced when the natural gas, i.e. Methane, or biowaste, is burned. The methods to synthesize the nanomaterials are usually divided into two classes. The first one is the Bottom Up methods which include the arranging of the molecules or the atoms in the nanostructures. The ingredients for this production can be in any physical state, i.e. solids, liquids, or gases. For solids, the material is first broken utilizing some sort of process, and then it is subject to the process of restructuring into nanostructured material. The other methods are termed as top-down methods as they are opposite to the first method. In these methods, some sort of mechanical energy is utilized to break the micro or macroparticles into nanoparticles. The ball milling is one such example. Lasers have also been used in this method. Hence, the former method uses the smaller than nanoscale particles to build a nanomaterial, while the latter uses the particles greater than the nanoscale to break them into a nanomaterial. The former method is preferred over the later one as there is better control over the properties of the nanomaterials in that method. These nanomaterials are then used for multiple purposes, including the prevention of pollution. It will be discussed further in this article.

Background

Nanomaterials are the result of recent technological advancement. They include the manipulation of the matter at the molecular and atomic scale and hence did not have much role in the past. With the limitless potential of nanotechnology, it was pursued, and the investments in this industry increased from four hundred and thirty-two million dollars to almost four billion dollars from the year 1997 to 2005. And from the year 2006 to 2011, the number of products utilizing the nanomaterials increased from two hundred and twelve to thirteen hundred and seventeen. It still has many uses as the knowledge about this technology is still limited, and the full potential is yet to be discovered. Many types of research and trials are going on these nanomaterials to find more uses.

Properties

The nanoparticles or nanomaterials are usually synthesized according to their role and the properties that might be required for that specific role. These are further divided into different types according to their structures and the number of dimensions which are in the nanoscale. Those with all three dimensions in the nanoscale are also known as nanoparticles. If these particles are joined to form a solid material, they are termed as the nanocomposite.

Fullerenes are one of the most important classes of the nanoparticles. They are the allotropes of carbon consisting of the graphene sheets which are rolled upon themselves. They have a very strong mechanical structure and also have electrical conductivity properties which makes them important for use in many industries. The fullerenes have been explored in their use as the carriers of antibiotics, especially for the resistant bacteria. They have the ability to target the microbes and even the tumour cells in the body very efficiently. They are usually formed by the graphite electrodes.

The inorganic nanoparticles have exceptional electrical and optical properties which make them very much useful in the photonics. They also have mechanical, chemical, and magnetic properties, which can be enhanced or diminished by minor changes in their production and suited according to the task at hand. These nanoparticles also have the ability to dissolve in the solutes. The surface area to volume ratio is very high, which helps the nanoparticles in diffusion. In addition to these, one dimensional and two-dimensional nanostructures are also available commercially. Also, the solid structures which are composed of the nanoparticles and also have the corresponding properties are known as bulk nanoparticles or nanocomposites. The melting points and boiling points vary according to the structure and are usually very high. Chemical properties also depend on the structure of the particular nanoparticle.

Applications

There is a wide range of applications of the nanoparticles as mentioned below:

  • They are used in the production of paints.
  • They have a role in providing insulation properties to different structures.
  • They are also added in the lubricants to increase the effects by reducing the friction further.
  • In the healthcare industry, they are often used in the form of enzymes usually termed as “Nanozymes”.
  • They have also been employed for detecting the different anomalies in the form of bioimaging or biosensing.
  • They are also utilized in the production of the filters which are so efficient that they even stop the viruses from passing.
  • They can also be utilized to control the pollution in different ways which are described below.
  • Sports industry utilizes them to produce baseball bats.
  • They are also used in sunscreen lotions in the cosmetics industry.

Role in preventing pollution

The pollution has been affecting human health very adversely, and the presence of toxic materials in all the surrounding environments has become a huge problem for mankind. However big is the problem of pollution, its solution is a very small one, i.e. nanomaterials. The nanomaterials can be used to prevent and control pollution in multiple ways. One way is to detect the polluting particles present in the environment. It can help by detecting many of the organic pollutants or heavy metal toxins in the environment. As the nanomaterials are recyclable and can be used again and again, they are very effective in this regard. Another way to combat pollution is by the role of nanomaterials as catalysts. They have been designed in special ways to absorb carbon dioxide from the environment. As we know that, carbon dioxide is one of the major pollutants of air and greenhouse gas, its removal to natural levels can result in the reduction in pollution and global warming. The nanomaterials can also be designed in such a way that they not only remove the carbon dioxide from the environment but also convert it into useful products such as alcohol.

These nanomaterials can also be used to reduce water pollution. The textile and leather industries have been known to produce very toxic dyes and byproducts. If these toxins find access to mainstream water, they could increase the cancer rates by hundreds of times. These are also very injurious to flora and fauna of the area. To treat such toxins, nanomaterials can be used which can capture these pollutants very efficiently and avoid the side effects. It has been widely studied by the scientists and approved the effective role of the nanoparticles in removing the dyes and heavy metals from the water. Works are also being done to capture the oil spills which kills all the marine life where ever the oil tanker leaks and the results are promising.

Another way to reduce pollution is through the use of these nanomaterials to digest toxic organic waste. Organic waste usually degrades by itself, but the process is very slow, and it can be accelerated by many folds by the use of these nanomaterials. The old way to dispose of the organic waste was to put them in digestors which digested the waste by the help of anaerobic bacteria and produced gas which could be used as a fuel. By the addition of nanomaterial enzymes, this process can be almost doubled, hence producing double the gas at the same time.

The nanotechnology is just starting to put its impact on the modern world. The potential to its uses is limitless. They can be used for many purposes and is being utilized by almost every industry currently. The role it has in the prevention and control of pollution is remarkable. Due to its exceptional properties of having a large surface area and the ability to work as a catalyst, it is a very efficient pollution reducer. It can help against all major types of pollution. To fight air pollution, it has the ability to adsorb the air pollutants such as nitric oxides, carbon dioxide, chlorofluorocarbons, etc. and hence reducing the acid rains, smog, and global warming. For water pollution, it has the ability to remove the toxins from the water and can be employed to treat the industrial wastewater before disposing of those waters. And, finally, for land pollution, it can help get rid of organic waste very rapidly. Along with these roles in reducing pollution, the nanomaterials can be used to produce useful products from these pollutants.

Twelve Principles of Green Chemistry:

The following list gives an overview of the making of a greener process, product, or chemical, developed by John Warner and Paul Anastas.

- It is smart and better to prevent waste than to create waste and then cleaning it up or treating it. - In the process to the final product, all the materials are incorporated, the incorporation is maximized by the synthetic methods which should be designed. - Methods of synthesis should be able to generate and use substances wherever possible, and substances have little or no toxicity to the health of a human and the environment. - For affecting their required function, chemical products should be designed while also lessening their toxicity. - Auxiliary substances' (separation agents, solvents, etc.) usage should be unnecessary whenever used, innocuous, and possible. - Instead of diminishing whenever economically and technically practicable, a feedstock or raw material should be renewable.

Nanografi's Horizon 2020 SME Instrument winner project: Green Graphene

Nanografi's Horizon 2020 SME Instrument winner project: Green Graphene

- Chemical processes have some requirements of energy that for their economic and environmental impacts, should be known and lessened. Possibly, at ambient pressure and temperature, synthetic methods should be conducted. - Stoichiometric reagents are inferior to Catalytic reagents (selective). - Avoid or lessen the unnecessary derivatization (blocking group’s usage, deprotection/protection, chemical/physical processes’ temporary modification) if possible, because additional reagent being required by such steps and such steps are capable of generating waste. - In a chemical process, the form of substances and a substance used should be chosen for minimizing the risk of chemical accidents, for instance, fires, explosions, and releases. - For chemical products to not persist in the environment, they should be designed just so, at their function's end, they collapse into innocuous degradation products. - Before hazardous substances are formed, further development is needed in Analytical methodologies to allow for real-time, in-process monitoring, and control.

Nano-cellulose as a plastic alternative

In many ways, plastic is a material of wonder, but the fastly growing environmental problem is plastic trash. Nanocellulose is an alternative solution to plastic, and it's a pseudo-plastic. It was first produced in 1983. Being the earth's most abundant organic substance, nano-cellulose is also a natural carbohydrate, extracted from wood or cotton. Also, extremely good barrier properties for mineral oils and oxygen are exhibited by nanocellulose as compared to plastic, thus replacing materials of barrier from fossil raw materials. In a broad range of areas, with its high strength, lightweight, transparent properties, and electrical conductivity, nanocellulose has a high amount of interest for different applications. It is completely biodegradable and non-toxic. The main applications are that nanocellulose is appropriate to be used instead of plastic as a cardboard's protective layer, and as a packaging material for food.Nanocellulose is also appropriate for many applications, for instance, flexible screens, medical implants, manufacturing of new environmentally friendly materials, replacing plastic in packaging, and repairing damaged tissue by helping the body, just to name a few.

CNC (Cellulose Nanocrystals) or NCC (Nanocrystalline Cellulose ...

Plastic is strong, easy to shape, and cheap in production but the fastly developing environmental problem is plastic trash. On the planet, for every individual, there are 44 kilos of plastic produced per year. Around 40% of plastic waste is made up of packaging. Now an urgent race is in the process to make a sustainable, biodegradable material that can replace plastic packaging. No doubt, great resources are card and paper with their characteristics of adaptability, high recycling rate, and protective, but still, a sustainable and strong material having translucent and barrier characteristics has a gap, where cellulose nanofibre comes in as it is an advanced biomass material. For the replacement of insulating foam and plastic film, a good option is nanocellulose for raw material that's used for packaging materials.Nanocellulose is so harmless that even if eaten, it's risk-free.

Nanocellulose is made by taking the wood chip's raw material and pulping them mechanically for creating wood fibres which later can be treated chemically for creating cellulose nanofibre. Molecules of cellulose snugly fit together, and every fibre contains a cellulose molecule's bundle. The sticking together of strong fibres makes the surface special, and that's why nanocellulose is used as tiny building blocks that join themselves together into very solid and small structures. Adding nanocellulose affects the water's viscosity as it turns into more viscous, making a different pattern of flow, therefore, allowing oil to be extracted from new areas of the reservoir.

Cellulose Nanofiber (Cellulose Nanofibril, Nanofibrillated Cellulose, CNFs)  Cellulose Nanocrystal (Nanocrystalline Cellulose,CNC)

When produced, many of the plastic's characteristics are exhibited by cellulose nanofiber. It's strong, lightweight, transparent, and has high barrier properties to gas and water. Nanocellulose is also used in cosmetics, medicine, replacing computer components, car parts, and even as a sustainable material in electronic devices for screens. In 1983, cellulose nanofibre was first produced, but in 2010, commercial production started because before 2010, there were high production cost and high production energy consumption. Cellulose is a natural carbohydrate and the earth's most abundant organic substance. It is a raw material because of being extracted from wood. Nanocellulose can replace barrier materials from fossil raw materials as they have very good barrier properties for mineral oils and oxygen. Nanocellulose being the biodegradable material is capable of replacing materials that are poorly degradable, thus lessening plastic waste and therefore opening up a possible way out of the environment's microplastic problem. It is more compatible with papers and other polymers and has not many problems in the process of recycling, and as compared to commonly used materials, nanocellulose leads to a higher recycling quality. If its development continues at the current pace, the non-organic plastics will be made obsolete soon. Trees are not even entirely used, just the branches and twigs or even sawdust can be used for the purpose, somehow waste is being turned into gold. Nanocellulose is capable of replacing plastic in multiple applications.

Production

Although, nanocellulose can be prepared from any source material of cellulosic but generally, it is produced from the pulp of wood. Once nanocellulose is parted from the pulp of wood, it's in a water suspension. A process is developed allowing nanocellulose to dry-out without the rough clump's formation, therefore, preventing the sticking together of cellulose fibrils and enabling the cellulose fibres, so that their mechanical properties can be retained.

Properties

A number of positive characteristics are carried by this material. It's non-toxic and biodegradable. Nanocellulose can be extracted from agricultural and forestry waste products. In bulletproof vests, Kelver is used, and nanocellulose is stronger than that and steel, per weight, and it's also electrically conductive. It is transparent, and as compared to plastic, nanocellulose is also a better barrier to oxygen. It's extracted from the matter of plant which consists of cellulose fibrils of nanosize and it is a substance that's light solid and pseudo-plastic. Nanocellulose has the characteristics of gels or fluids of specific kinds which in normal conditions are thick. Nanocellulose's dimension of longitude varies from a few 10 nm to several microns, and lateral dimensions range from 5 to 20 nm. In high quantities, they are produced cost-effectively. When used as a basis for foams and aerogels, nanocellulose is highly absorbent. It is the earth's most abundant polymer.

Applications

For many applications, nanocellulose is appropriate; for instance, medical implants, a scaffold for the engineering of tissue, flexible screens, just to name a few. An alternative that's environmentally-friendly for petroleum-based plastics that are used greatly in packaging is also provided. It's high strength and lightweight makes it capable of replacing metals with increasing efficiency. Nanocellulose aerogel is used to create a boat that could support a thousand times its own weight. Nanocellulose has a broad number of applications ranging from oil spills cleaning to children's toy usage. It's also used in food, medical, and pharmaceutical industries. Nanocellulose is a cheap alternative to glass fibre and carbon fibre for few applications and is also measured as an important material by the pulp and paper industries.

The protective layer on Cardboard

Nanocellulose fibres are used as a protective layer on Cardboard that is used for packaging or wrapping later. Aluminium and Plastic packaging can now be replaced in many applications, especially metal-based materials and non-renewable petroleum materials which are used in drinking cartons, etc. Nanocellulose is applied to paper or Cardboard to obtain a fine, smooth surface. A barrier is created by the nanocellulose, which protects the internal content from external influences. The rough Cardboard that was used had pores of large size and was uneven, and with just a single individual layer of nanocellulose, that Cardboard changed from a rough, uneven surface to an even and smooth product. The absence of cracks and holes tells that the nanocellulose' properties of the gas barrier are adequate. Density and smoothness make it easier to implement decent graphics like text and logos with less printing ink because, on paper, it will stay on a smooth surface instead of being absorbed. On top of the Cardboard, a layer is formed by nanocellulose, even over the uneven pores, just like a thin skin. Most of the materials that are applied to paper and Cardboard penetrates the pores, but instead, nanocellulose when dries, forms a fine film, possibly due to the number of hydrogen bonds in between the nanofibers. Gas barrier properties of nanocellulose are discovered and described by the researchers. No matter which Cardboard is used, calculating the nanocellulose amount that's required per square meter of Cardboard is easy. It is quite robust and can be placed on a range of surfaces reliably with a similar result, smooth skin with some holes per square meter, and accordingly decent barrier properties.

Manufacturing of new friendly environmental materials

A tough material results when a polymer is mixed with wood fibre broken down to the nanoscale or Nanocellulose. Composites that are made of cellulose and poly (lactic) acid (PLA) were studied. PLA is toughened by even cellulose in small amounts. When the cellulose amount in the composite was less than 5 %, the composite toughness was about ten times higher as compared to pure polymer.In about several months, this composite material decomposes into carbon dioxide and water without doing any harm to nature. Both brittle polymers, cellulose, and PLA are joined to form one tough material. For achieving remarkable characteristics, the nanocellulose should be distributed within a polymer evenly.

Packaging and Paper Industry

In the packaging and paper industry, nanocellulose is majorly adopted to replace the synthetic polymers use that's derived from petrochemical resources. Nanocellulose has a nanoscale dimension with barrier properties of water and gas, which can be used for developing films of nanocomposite with a strong building network to pass the penetrant molecules through. Polylactic acid (PLA) matrix and Nanoclay was developed with Nano-biocomposite film for packaging of food, having the reinforcing agent being nanocellulose that leads to an important improvement in oxygen and water barrier properties.

Food packaging

A sustainable, biodegradable alternative to plastic packaging. It completely disintegrates in less than a month. Plastic has long been the material of choice for food packaging, but due to its large carbon footprint, high levels of pollution, and low recycling rates, plastic has become the scourge of the century. Now, EcoFLEXY is for the food packaging market.As a bio-cellulose material, EcoFLEXY is highly recyclable. It can completely disintegrate at room temperature in under a month – a significant improvement over conventional plastics, which can take anywhere from 20 to 1 000 years to decompose. EcoFLEXY is seen as having a unique value proposition to replace the large quantity of multi-material plastic packaging that is never recycled. This involved much more than expanding the volume of production, as it also required us to ensure that the product fits into packaging line machinery. To stop the oxygen from entering into the content of food and to avoid the spoiling of food, nanocellulose is used as a material for food packaging.

Replacing plastic in packaging materials of future

The aim is the development of biobased packaging which can be used over long distances for transporting goods, like, for fish transportation. Thin-film of nanocellulose and plasticized cellulose coats the developed packaging, therefore offering a barrier against oxygen, meanwhile, during transportation, low temperature is maintained by the insulation that's offered by a foam core of nanocellulose and plasticized cellulose in the packaging

Nanocellulose is the super material for replacing plastic in many applications. Cellulose nanofibers is the most advanced biomass material and displays most of the plastic's characteristics. It's strong, lightweight, transparent, and electrically conductive with high barrier properties to gas and water, as compared to plastic, thereby reducing plastic waste. Produced from wood pulp, nanocellulose can also be applied as a material for food packaging, and it stops the oxygen from entering into the content of food, prevents the content of food from being spoiled, and also used on Cardboard as a protective layer, just to name a few.

How Could Cellulose Nanomaterials Improve Capacity for Renewable Energy Storage?

Nanocellulose is a new type of nanoparticles that have emerged as promising nanomaterials to produce eco-friendly renewable energy storage devices. Its unique properties, suitable structure, cost-effectiveness, and natural abundance has made sustainable and promising nanomaterial. Cellulose nanomaterials, including cellulose nanocrystals and cellulose nanofibrils, have unique and attractive properties, especially renewable energy sources, are being exploited in different industries, including environmental protection, energy harvesting, and storage, etc. This advancement of technology is certainly a revolution and an important milestone in human history. Using such an abundant, affordable, and renewable substance for the service of human beings, along with ensuring the protection of the environment is truly remarkable. However, the research is still going on for more innovations in the field of nanotechnology, including nanocellulose that is already a field progressing at an unprecedented pace.

Nanotechnology is the science, technology, and engineering that revolves around nanoscale particles of about 1 to 100 nanometers. It is the study of extremely tiny things and their potential applications. The study has found its uses across several other scientific fields such as material sciences, biology, chemistry, physics, and engineering.

Nanocellulose – Cellulose Suspension

A physicist Richard Feynman started a discussion entitled "There is plenty of room at the bottom" at a meeting of American Physical Society on December 29, 1959. After a very long time, Professor Norio Taniguchi used the term nanotechnology for this new science. Feynman, in his talk, spoke about new possible ways to manipulate and control atoms and molecules of different elements. During the 1980s, a scanning tunnelling microscope paved the way for the scientists to see individual atoms and hence, at last, the nanotechnology started its never-ending journey. No one knew back then that it would cause great wonders one day.

Do you wonder how small nanoparticles are? It is too small beyond our imagination. Particles of 1 to 100nm are involved in nanotechnology, and 1 nm is a billionth of a meter. Now, can you imagine how small nanoparticles are and how these tiny materials are controlled for the service of mankind? Let's share another scale to help you resolve your curiosity. One inch has 25,400,000 nanometers.

In the midst of these technological advancements of the contemporary scientific era, some real concerns are also there that need the attention of human beings. Among such issues, environmental protection and renewable sources for energy are the most serious and grave. To tackle those issues, scientists embarked on a relentless journey to discover new ways to protect our planet by finding new ways to find, convert, and store energy. In this build-up, nanocellulose has emerged as a potential candidate for renewable energy storage. The easy availability, simple synthesis techniques, low cost, and above all, eco-friendly nature render it one of the most efficient and effective nanoparticles for the production of green renewable energy storage applications.

What are Cellulose Nanomaterials?

Cellulose particles gave nanotechnology a new aspect to look into. Cellulose nanomaterials are a new kind of the cellulose particles that are significantly distinctive and different from molecular cellulose in terms of properties and functionalities. Nowadays, they are being developed and improvised for use in applications that once seemed impossible for simple cellulosic substances. The research and development process of the cellulose nanomaterials is accelerating. The commercialization of that miraculous nanocellulose because of unique properties such as sustainability, high mechanical properties, production potential at a larger scale, etc. The rise in popularity of these materials is also based on the usability of these materials in myriads of material applications. This is really a revolution as far as material sciences are concerned. Science has gone beyond the imagination of the human mind. The production of these remarkable nanoparticles is rapidly expanding because of the numerous advantages they offer. They are extensively used to develop renewable energy storage devices, super-capacitors in particular.

Cellulose nanomaterials and renewable energy storage

A few decades ago, a surge in search of high-performance energy storage systems began that led scientists to new classes of materials and structures. Among those, nanocellulose also emerged that has the potentials to solve many problems the world is currently facing. The chemical and physical properties and the unusual structure of the cellulose nanomaterials offer unprecedented advantages for the fabrication and performance of energy storage applications that would not be possible to achieve with the traditional materials to manufacture storage devices. Traditionally, the elements of the energy storage systems relied on the inorganic/metal compounds, hydrocarbon chemicals derived from petroleum, and carbonaceous substances. It is highly unlikely that all those materials are capable of fulfilling the ever-increasing need for energy storage devices. Nanocellulose, on the other hand, is naturally abundant, recyclable, and eco-friendly material that is the best to manufacture energy storage devices.

How nanocellulose can improve the energy storage capacity of devices

Nanocellulose is a nanomaterial that is now abundantly available in the market. It has found its various uses across different industries. Currently, it is most famous for its use in energy storage devices, and it has a huge potential to improve the energy storage capacity of the devices.

Nanocellulose-based composites for supercapacitors

Supercapacitors

The future of the energy storage devices is supercapacitors because of their numerous advantages. They are easy to maintain with negligible maintenance costs, rapid charge and discharge rate, long life cycle, can operate a range of temperatures, high power, high energy density, and high shelf life. Nanomaterials are popular for having a large surface area and several other unique characteristics that simple atoms or molecules cannot have. The high surface area of the nanocellulose allows the supercapacitors to increase the adsorption of ions at the interface. High surface area increases the adsorption at the interface that significantly enhances the energy storage capacity. Such supercapacitors are of two types, electrochemical double-layer capacitors, and pseudocapacitors. The former has a higher power capacity while the latter exhibits high energy density. Nowadays, the modern hybrid supercapacitors combine both of these types and are preferred over conventional batteries because of having high energy density and capacitors because of having high power density. Nanocellulose is also being used as a separator, electrolyte, or binder material.

Electrodes

The modern electrodes that are made of polypyrrole along with cellulose nanocrystals through the electrochemical deposition process. These electrodes are far more superior to electrodes made of polypyrrole doped with Cl.

Aerogels

Nanocellulose-based aerogels large surface area, have a very low density and are highly porous. These aerogels are used in combination with other active nanoparticles to enable them to store a significantly higher amount of charge.

3D-Supercapacitors

3D supercapacitors and energy storage devices are now being developed to further improve the energy storage capacity of the devices. Three-dimensional cellulose-graphene structures are being developed for this purpose. It has been observed that the capacitance increased to approximately 90.3% of its original level after 2000 cycles. Initially, aerogels were used in the 3D electrodes, but now, wood-based materials are also being used. However, there are certain limitations in this regard that needs to overcome. In terms of 3D architecture, several different parts of energy devices utilize nanocellulose that significantly improves the electrochemical performance of the energy storage devices. Current collector and separator membranes are among the most common examples in this regard.

Ultrathin energy storage

Ultrathin devices are also a new innovation in order to increase the energy storage capacity of the storing devices. Although the capacity of these devices is comparatively less, yet these devices are a significant milestone in pursuit of improving the capacity of renewable energy storage capacities. There are a number of devices ranging from 1D to 3D devices that are being fabricated to capitalize on the fibrous nature of nanocellulose. One example that can be quoted here is 1D microfibers coated with carbon nanotubes that act as electrolyte reservoirs.

Flow batteries

Flow batteries have also been tested and exhibited remarkable results as far as renewable energy storage devices are concerned. Cellulose-derived nanomaterials are used as a membrane within the flow batteries to store energy that is extracted from renewable energy resources such as wind power and solar energy. Flow batteries are giant batteries to store and generate energy. They consist of a huge tank full of electrolytes. Another key part of those batteries is a selective ion membrane that facilitates the hydrogen ion movement. Hydrogen ion movement is imperative to balance out the charges on both sides of a cell. Nanocellulose has proven itself the better choice material for ion membrane as compared to other traditional materials commercially available in the market. The presence of hydroxyl and acidic sulfonate groups show high proton conductivity, significantly enhancing the Coulumbic efficiency, energy efficiency, and current density. These nanomaterials also significantly enhance the efficiency and life of the flow batteries. With the advancements of technology and new developments in the field of nanotechnology, these membranes can also be introduced to complex power grids that have the capacity to store energy from both sources, renewable and non-renewable.

Nanocellulose in energy conversion devices

Nanocellulose and other biomaterials are also being used in energy conversion devices such as in solar cells to convert solar energy. Traditionally, organic and inorganic materials are used in solar cells for conversion purposes that are expensive and also non-renewable resources. Nanocellulose, on the other hand, is cost-effective and renewable as well. Conversation devices need a large surface area to convert solar energy, and that is the basic property of the nanomaterials, i.e. having a large surface area.

Organic photovoltaic devices have also been tested with nanocellulose, and they exhibited higher efficiency because of low roughness, smoother films, and more homogeneous distribution of fibres. Nanocellulose is also being used in Perovskite solar cells and dye-sensitized solar cells that are less expensive but higher energy conversion.

Nature is generous and has a lot of secrets for us to reveal. Cellulose is just one among billions of those secrets. It is the most abundant natural polymer. It is now being developed into nanocellulose to serve many purposes. Nanocellulose has unique physical and chemical properties that are useful in several different applications. It significantly improves the batteries and electrical grids to save renewable energies. We cannot sustain on non-renewable resources for energy, and we cannot store enough energy from natural resources such as wind and sun unless we develop batteries with large storage capacities. That is where the need for large batteries powered by nanocellulose comes in. This is one of the biggest advantages of modern technology that both of the key elements are naturally renewable, source of energy, and source of storage batteries.

Conclusion

The nanostructured materials which are 1–100 nm in size are very well known for showcasing excellent mechanical and physical properties. Initially, all the researchers were merely focused on the synthesis of nanomaterials but now they are more focused on synthesizing the nanomaterials to produce useful structures from them. This brief review provides synthesis, characterization, applications of nanotechnology in the current scenario. In particular, the top-up approach and bottom-down approach were discussed. The understanding of green nanotechnology has significantly reduced the burden on future generations. Given that an essential role is played by the nanotechnology in the development of novel polymeric materials, the next generation of the advanced materials will further utilize nanotechnology to improve the properties of the advanced materials. Overall, this review emphasizes the contribution of nanotechnology and green nanotechnology in modern functionalized advanced/smart materials.

References

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14th Sep 2020 Arslan Safder

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