“The future belongs to those who believe in the beauty of their dreams.”
By Eleanor Roosevelt.
The “Smart” concept is becoming popular thanks to technologies such as Smart Cities and Smart Contracts. Furthermore, in the case of Smart Materials, it will be highly relevant due to its capacity to change many of the current industries, since it will help to make them more efficient, safer and cheaper. The objective of this article is to discover how materials science is evolving to help us improve current models of use of all types of materials, so that they can offer us a better service, especially through robotics, which is where Present a greater future utility.
Intelligent materials are those that show an observable effect in one of their facets when stimulated from another. In this way all facets are covered, including mechanical, electrical, chemical, optical, thermal, etc. Some examples of intelligent materials that can add new capabilities to robotics and artificial organisms are thermochromatic materials that show a color change when heated and electroactive polymers that generate a mechanical benefit when they receive electrical stimulation. Intelligent materials can be hard, like piezo materials; flexible, such as shape memory alloys; soft, like dielectric elastomers; and fluids, such as ferrofluids and electrorreological fluids. In this way, if we need a robot that can detect chemical products, we can build it using intelligent material that changes its electrical properties when exposed to the chemical in question and if we need a robotic device that can be implanted in a person. Degrade until it disappears when it has fulfilled its function, we can create it with biodegradable, biocompatible and selective dissolving polymers.
To know the degree of utility that these new intelligent materials can offer, it is possible to calculate their intelligence coefficient, when evaluating their response capacity, agility and complexity, so that if we combine multiple intelligent materials in a robot we can greatly increase their coefficient Intelligence. In addition, state-of-the-art robotic technologies can be divided into three groups depending on the utility offered by intelligent materials: hydraulic and pneumatic soft systems; intelligent materials such as sensors and actuators; and materials that change rigidity. In this way, through the use of intelligent materials, soft robotics is gaining prominence thanks to the resurgence of fluid impulse systems combined with a greater understanding of the modeling of elastomeric materials.
Types of Intelligent Materials
Scientists who are dedicated to the study and development of new materials have made a classification of what are called intelligent materials for their ability to react to certain stimuli, as if they were programmed to perform specific functions. Thanks to this capacity of some materials the possibilities of use are amplified, in areas of the technological industry such as robotics, internet of things and the production of renewable energies. Let’s see below what these materials are and their main characteristics.
The luminescence is all process of emission of light whose origin is not exclusively due to high temperatures but it is a form of “cold light” in which the emission of light radiation is caused in ambient or low temperature conditions . Depending on the energy that originates it, it is possible to speak of several types of luminescence: photoluminescence, fluorescence, phosphorescence, thermoluminescence, chemiluminescence, triboluminescence, electroluminescence and radioluminescence. Depending on the radiation that stimulates the emission of light, we will have the following luminescent processes:
Photoluminescence: It is a luminescence in which the activating energy is of electromagnetic origin (ultraviolet rays, X-rays or cathode rays).
Catodoluminiscencia: if the origin is a bombardment with accelerated electrons.
Radioluminescence: if the origin is an irradiation with α, β or γ rays.
Piezoelectric: are those that when subjected to mechanical stress acquire an electrical polarization in its mass and a difference of potential and electrical charges appears on its surface. This phenomenon also occurs in reverse: they deform under the action of internal forces when subjected to an electric field. The piezoelectric effect is normally reversible: by not subjecting the crystals to an external voltage or electric field, they recover their shape.
Chromoactive: are the materials in which color changes occur as a result of some external phenomenon such as electric current, ultraviolet radiation, X-rays, temperature or pressure. They can be classified as:
Thermochromic that reversibly change color with temperature, this color change occurs within a range of temperatures and are usually semiconductor compounds.
Electrochromic devices have the property of changing absorption spectrum and, generally, of color, by changing their oxidation state by the application of an external potential difference.
Photochromic reversibly change colors with changes in the intensity of light. These types of materials are not seen in dark places. When sunlight or UV radiation is applied on the molecular structure of the material, it changes and a color appears, which disappears when the source ceases.
Materials with memory: they are those that have the capacity to remember their shape and are able to return to that form after having been deformed. This memory effect can be produced by thermal or magnetic change and are also able to repeat this process many times without deterioration. These materials can be alloys, ceramics, polymers and ferromagnetic alloys.
Applications of Intelligent materials
The materials we have just learned are offering an infinity of applications to amplify the possibilities of all types of technologies, here we will describe some of them.
When in Futurizable we dedicate a specific article to the batteries we emphasize the importance of the development of new materials to amplify the efficiency of the batteries. In this sense, many new advances continue to be made, such as those achieved by the Spanish scientist of the CSIC, Gonzalo Murillo, who develops a new type of batteries that converts mechanical energy into electricity thanks to piezoelectric materials that transform vibration into voltage. For this, they use devices designed to feed tiny sensors placed in vehicles or objects connected to the Internet, which are capable of generating a few milliwatts, by compressing the piezoelectric material, generating a charge separation that in turn produces electrical energy. To achieve this compression, a miniaturized structure is designed that resonates at a certain frequency. Thanks to this technology you can feed different types of wearable devices and also hearing aids.
There is no doubt that 3D printing is serving as a catalyst for everything that has to do with the development of new materials, especially for having invented a new form of manufacturing and having made manufacturing processes accessible to many more people, which is leading to more and more interest in having new materials with specific properties. To answer this growing need MIT engineers led by Sebastian Pattinson have developed a system that replaces petroleum-derived polymers that are commonly used as 3D printing material by a type of vegetable cellulose that offers many advantages over the traditional system. It is a renewable, biodegradable alternative that provides a cheaper, more resistant material that also has antimicrobial properties. To this end, cellulose acetate is used, which allows its use in the extruders of the printers and when the acetate evaporates, the material solidifies quickly. Thanks to this it is possible to print objects whose hardness is greater than that achieved with the majority of materials commonly used in 3D printing, including ABS and PLA.
The impressive business that companies such as Apple and Samsung have achieved thanks to smartphones has led to great advances in the development of screens, which are increasingly larger and have significant improvements in terms of resolution and interaction. In addition to this, the aspect of resistance is very important, which is precisely what scientists from the University of California, Riverside, led by Chao Wang, who have developed a new material capable of repairing only that is specially designed for the screens of smartphones. For this they use polymers that are able to close the cracks produced on the screen after an impact, without requiring human intervention. This material has properties that allow it to stretch up to fifty times its natural size, counting on a performance very similar to that of human skin in terms of its repair, because when we make an open wound, the ends are stretched until closed completely. It is the first conductive material of electricity that has the ability to repair on its own, which is especially recommended for use on touch screens of mobile devices.
The space race is at its peak after the entry of a number of private companies to perform activities related to space and the reactivation of space programs by NASA and other space agencies at the government level. To face this boom in humanity’s interest in conquering space, it is necessary to move forward in the development of new materials for ships as well as for other types of objects, such as the costumes of astronauts. An example of this is a new material developed by a NASA team led by Raul Polit Casillas, through 3D printing and that can be used for different purposes. It is a new type of fabric that has the following operation: the upper part reflects light and keeps heat away, while the interior has an insulating effect, protecting what is inside, whether an object, an enclosure or a body human. For their development they have used a process that they have called 4D printing, since in addition to building three-dimensional pieces, they also manufacture functions for the material. In addition, the manufacturing process of this new material is designed to take advantage of the natural resources that can be found on the planet where it will be used and therefore carry out on-site manufacturing, in addition to allowing its recycling for the manufacture of other products based on this material. To know more about the activity carried out by NASA in the field of materials, we can consult the web page of its Smart Materials department.
Although the generation of clean energy is still insufficient to remedy the great problem we face with pollution and global warming, we can consider that the situation is improving considerably thanks to the multitude of advances that are being made in terms of research for the generation of renewable energies, mainly for obtaining energy from the Sun. This is the case of the work carried out by researchers from the Laboratory of Characterization of Organic Devices of the Rey Juan Carlos University together using a new material called hybrid perovskite methylammonium with the goal of developing cheaper solar cells. Hybrid Methyl Ammonium Perovskite has a certified efficiency of 20% and is positioned as a cheap alternative to current technologies for the manufacture of thin-film solar cells, since it allows the use of much simpler manufacturing techniques at low temperature (< 150ºC), allowing new applications. The results of this research represent an important advance for the manufacture of thin-film solar cells, since the current technology is based on inorganic materials such as cadmium telluride (CdT) or copper, indium and gallium selenide (CIGS) that use more expensive manufacturing techniques and with high process temperatures (> 500ºC)
The improvement of the materials used in construction, such as cement, concrete and asphalt, are the objective of a multitude of investigations aimed at offering improvements in terms of resistance, efficiency and cost reduction, among other things. This is the case of the work carried out by the researcher Gloria Pérez of the Eduardo Torroja Institute of Construction Sciences of the CSIC to develop, thanks to nanotechnology, an eco-efficient and thermochromic cement that changes color with temperature and can be used as an intelligent coating. In the same research center Ana Guerrero develops her work with the aim of creating a new type of concrete that has the capacity to repair itself. Unlike other investigations with concretes that self-repair from the outside, the objective in this case is that the material can achieve it from inside, thanks to contain silica microcapsules filled with epoxy that break when a crack in the concrete occurs to be able to repair it. In the case of asphalt, a job is developed at the Technological University of Delft by the engineer Erik Schlangen, who hopes to double the useful life of the asphalt by adding some small steel wool fibers that have the ability to melt the asphalt when it is provided. an electric current, which allows to recompose the mixture of asphalt and gravel that is used as pavement for roads. Another application of intelligent materials in the field of construction is the development of Intelligent structures, which are those that thanks to the combination of intelligent materials are able to self-diagnose and modify to adapt to the conditions that have been marked as optimal or correct .
The development of sensors for the large field that is being opened by means of IoT technologies is one of the utilities that will be offered by the research carried out in the Graphos project, led by the chemical specialty company Cromogenia and which proposes the objective of achieving the incorporation of graphene and carbonaceous nanostructures in a wide range of polymer matrices, with which it is expected to achieve their integration in various products with advanced functionalities and improved physical-mechanical properties.
Thanks to the development of all kinds of new materials, progress is being made enormously in the development of soft robotics, a new technological discipline that will allow a breakthrough so that robotics offers us better utilities for people. This is the area in which he develops his activity Jonathan Rossiter, professor of Robotics at the University of Bristol and researcher of the EPSRC, who works on the creation of new materials that help to cure diseases through research such as the design of a robotic skin that integrates with the human. These intelligent skins mimic the abilities of some animals, such as being able to blend in with the environment or regulate body temperature. The scientist works on the development of smart bandages capable of healing wounds and also investigates how to replace conventional clothes with a kind of second skin that adapts to the body. Thanks to these innovations, elderly people or people with disabilities can also be helped to regain mobility, so that in the future wheelchairs will be replaced by movement boosters.
In the union of technology with biology we find one of the main levers for the evolutionary leap that humanity is currently making, in search of new horizons, both at the level of amplification of life and in what refers to the exploration of space. For both aspects, the advances that are being made through bionics will be fundamental, as is the case with Stina Simonsson’s research at the Sahlgrenska Academy of the faculty of health sciences of the University of Gothenburg in Sweden, which has been able to regenerate cartilage cells collected from patients who had undergone a knee operation, and then manipulate them in a laboratory to rejuvenate them, returning to the state of pluripotent stem cells, which are stem cells with the potential to become cells of many different types. These stem cells have the ability to spread after being encapsulated in a nanofibrillated cellulose compound that is printed to serve as a scaffold through the use of a 3D bioprinter.
The use of new materials and materials in the world of transport can generate important benefits in terms of reducing pollution, reducing the cost of fuel and improving the efficiency of vehicles. We also see that all types of transport can benefit from these advances, as is the case of bicycles where we find interesting innovations such as the one made by the Spanish company Racormance, which has created the first bicycle in the world made of basalt fiber. . The company uses basalt fiber for its excellent absorption properties of impacts and vibrations. In addition to other major value propositions of the company, is its commitment to manufacturing 100% Made in Spain, as these young engineers, perform all the process in their facilities, from engineering to the manufacture of tubes and final assembly of the complete picture.
The world of fashion and clothing still has much to improve thanks to the development of new materials, such as those used by researchers from the Massachusetts Institute of Technology, led by Wen Wang, to create new garments for sports training, which have the Features of being breathable by having ventilation flaps that open and close in response to heat and sweat. These ventilation flaps are lined with live microbial cells that contract and expand in response to moisture changes, acting as sensors and activators, to cause the flaps to open when an athlete sweats and closes when the body cools. Scientists work on a model with which it is possible to combine our cells with genetic tools to introduce other functionalities in these living cells. For example, using fluorescence to make people who are running in the dark visible. It will also be possible to combine the functions of release of odors through genetic engineering, so that maybe after going to the gym, the shirt used can give off a good smell.
Other interesting research in the field of new materials
Beyond the sectors that we have just described, a lot more research is being done both to create new materials and to find new applications for existing ones. These are some of the most recent research in the field of materials science:
A team of scientists from the University of Minnesota has synthesized a transparent material that presents a great driving capacity. This new material adopts sheet form and is the most conductive of its kind, so it can offer an important utility in the field of electronics. The peculiarity of this nanomaterial has its origin in the forbidden band, which identifies semiconductors. In this case the band is wide and when this happens, either the conductivity is low or the compounds are not very transparent. But in this case the synthesized material has two virtues that do not usually go hand in hand: conductivity and transparency. Thanks to this it can be used for the manufacture of screens, touch panels and even solar panels.
Researchers from the Technological Center of Plastics (Andaltec) participate in the European project GraFood, which aims to develop an innovative container for food based on graphene thanks to which food can be kept in good condition for longer. The use of nanomaterials in food packaging will also allow the amount of food that is wasted to decrease, increasing the conservation of packaged food products. For this, the researchers have proposed the creation of an active container based on paper and polylactic acid (PLA) modified with graphene oxide activated by probiotics and by nano-Ag-TiO2.
Scientists at the University of Heilongjiang in China have developed a new technique to produce graphene from the biomass generated with the cellulose present in corn cobs. Thanks to this new technique, traditional methods of obtaining graphene are improved, which are hampered by long production periods and limited production capacity, in addition to producing environmental contaminants.
Researchers at the Erlangen-Nürnberg University have developed a new invention in the field of lighting called Bioled, in which through biotechnology it has been possible to create a light bulb that works thanks to proteins or DNA with fluorescent properties. The luminescent components contain a protein polymer that forms the capsule or rubber wrap that covers part of the diode. Proteins, which are manufactured by bacteria, have the ability to emit pure white light after being excited by other light sources such as blue or ultraviolet LEDs.
An international team of scientists, led by Jan Johansson and Anna Rising of the University of Agricultural Sciences of Sweden, has designed a new method to produce artificial spider silk, bio-inspired in natural spider silk, but with properties that make it more resistant and cheap to obtain, offering uses as diverse as textiles for the absorption of impacts or advanced medical devices. To achieve this, they have been inspired by the way spiders make silk to develop hybrid protein, which includes sequences of amino acids present in the silks of two different species of spiders, in order to control the coagulation of proteins, mimicking the process of natural spinning in the spiders themselves.
Scientists from the University of Tokyo led by Takao Someya have developed a new printable elastic conductor that retains high conductivity, even when stretched up to five times its length. Its shape is pasty ink, so it can be printed on fabrics and rubber surfaces, functioning as an elastic wiring that can be used for wearable technology products that incorporate sensors, as well as to give robots functions similar to those of human skin
A team at the University of Berkeley has discovered a material that violates the law of Wiedemann-Franz that indicates that when an electric current passes through a metal material, it is heated. However this new material called vanadium dioxide at room temperature has a thermal conductivity is up to ten times lower than it should be. Thanks to the properties of this material can be used for example for the design of new engines that dissipate heat or to make window coverings that can dissipate the temperature in summer and avoid the loss of heat in winter.
A team of researchers at MIT has discovered that graphene grading and fusing them into a mesh structure not only retains the material’s strength, but also keeps graphene porous. This new material, with its particular geometry, is stronger than graphene, and exactly 10 times stronger than steel, having only 5% of its density. This demonstrates that the crucial aspect of the new three-dimensional shapes has more to do with their unusual geometric configuration than with the material itself, suggesting that similarly strong and lightweight materials could be made from a variety of other materials by creating of similar geometric characteristics. This new material that is extremely strong and exceptionally light will have many applications in sectors such as infrastructure construction.
A research by the Catalan Institute of Nanoscience and Nanotechnology led by Clivia Sotomayor reveals that optomechanical silicon crystals, which are designed on a nanoscale to confine photons and quantum mechanical motion units, called phonons, in the same physical space, could encode data by the chaos, which could change the future of telecommunications. This research could be the basis for the development of a new technology for the transmission of encoded information, combining phononics, photonics and radio frequency electronic signals.
Researchers from the Caltech and the Berkeley Lab in the USA, led by John Gregoire, have developed a method that allows discovering at high speed materials capable of turning water into fuel. Thanks to this advance, the substitution of coal, oil and other fossil fuels for commercially viable solar fuels could be accelerated. Solar fuels are made up of materials that can capture and store solar energy in their chemical bonds for later use when necessary. To this end, materials called photo-anodes are used, which has the ability to divide water using light as an energy source.
We have just met 10 examples of technological advances in materials science, mainly in what are known as intelligent materials, which are helping technologies such as robotics, the internet of things and 3D printing have a greater journey in the goal of helping humanity to evolve and solve the problems that are found in this process.