The advancement of material technology actively facilitates modern technology development in fields like electronics, construction and transportation, as the latter very often requires the presence of materials with specific properties so as to meet specific applications. For example, the development of high performance computing and high-speed network would not have been possible if without the invention of low transmission loss materials. For the design, synthesis and application of these kinds of advanced materials, knowledge about various scientific spheres is essential. Amongst all the spheres, chemistry plays a significantly important role.
Structural materials and electronic materials
Structural materials are materials that primarily emphasize mechanical properties. They serve to withstand a force, and/or to provide support and are widely used in every aspect of life. In addition to sheer mechanical strength, researchers are trying to produce multifunctional materials, for example, self-healing concrete.
Meanwhile, stepping into the era of electronics, the urge for more advanced and sophisticated electronic materials is intensifying. For instance, to build more efficient electronic devices while minimizing the sizes, semiconductors of better performance are necessary. Apart from that, superconductors, molecular electronic devices, and light-responsive materials are some hot topics in the field.
Recent research directions
Self-healing concrete by capturing carbon dioxide in the air link
Inspired by the transport of carbon dioxide in the blood, researchers reported that simply incorporating the enzyme carbonic anhydrase into the concrete powder could yield a self-healing concrete material. When a crack forms, the enzyme will capture carbon dioxide in the air to produce calcium carbonate to fill the crack. It is reported that millimeter-scale cracks can be repaired within 24 hours.
A superconducting material that works at 58 degrees Fahrenheit, despite it only lasted for minutes and under extreme pressure, was fabricated. Superconductors ever reported are only superconducting under extreme temperatures. This is the first one that works at everyday temperatures.
Novel self-assembly strategy for complex semiconductors link
Conventionally, stacking one 2D material on top of the other takes much effort and is limited to small-scale production only. In this news, researchers reported that adding a barbell-shaped chemical that serves as template for a kind of 2D material at each end can lead to spontaneous stacking of two kinds of 2D materials.
Graphene and its derivatives, and 2D materials
Graphene consists of a single layer of carbon atoms arranged in a hexagonal lattice structure like a honeycomb. It is one of the layers in graphite. Since its first isolation and characterization by peeling off from graphite in 2004, graphene has attracted much attention due to its outstanding physical properties. It is the thinnest, yet the hardest nanomaterial by far we know. Moreover, it exhibits excellent electrical conductivity and unusually high optical opacity. Thus making graphene a promising candidate in many fields of materials science. In addition to graphene itself, more and more extensive research has shined light on its derivatives such as graphene oxide and bilayer graphene.
Furthermore, the discovery of graphene has opened the door to 2D materials which are crystalline materials consisting of single- or few-layer atoms with thickness typically thinner than 10 A°.
Graphene oxide foam was found to be highly efficient in removing uranium as a precipitate from water by applying an electric charge to it. The graphene oxide foam may be used up to 7 times before inactivation and can capture up to 4 times of its own weight of uranium each time.
The effectiveness of applying invisible graphene oxide as a protective layer on silicon to stay away from ambient oxygen was evaluated. It was found that the layer can at least last for 30 days. Similarly, researchers expect that graphene oxide can also be used to protect artwork and electronics from moisture and oxygen in the air.
Graphene-based, self-powered nanotransistor devices were built and tested to be successful in measuring flow rate. It is by far the smallest and the most sensitive flowmeter ever reported. It can detect flow rates as low as a micrometer per second. Ideally, it can be implanted into patients to monitor biofluidic flow, which is a key physiological parameter.
A material produced by stacking 2D sheets of molybdenum disulfide has set a new record of directional heat control, researchers reported. Its excellent thermal conducting property can be utilized to keep computer chips from overheating by dissipating heat accumulated quickly.
Bio-inspired, bio-mimic, and bio-based materials
Nature always offers scientists role models and ideas on developing new materials because naturally occurring biochemical systems are elegantly “designed” and exhibit superior performances in terms of physical properties and catalytic activities. Therefore, chemists are seeking ways to artificially replicate, at least part of, these complex biochemical systems by synthetic means. Furthermore, starting from naturally occurring materials, especially those usually considered as waste, is particularly attractive in terms of cost, safety, and sustainability.
[FeFe] hydrogenases are the most efficient enzyme to generate hydrogen gas by photochemical reaction. Unlike the industrial generation of hydrogen requiring the use of electricity and expensive platinum catalysts, [FeFe] hydrogenases contain one iron(I) core and one iron(II) core in its oxidized state and are photochemically driven.
Making catalytic production of hydrogen more efficient and affordable means that fuel cells, which are considered green, stable, and efficient, are more likely to become one of the main sources of energy.
Over the years, researchers have prepared many kinds of catalysts mimicking the active site and the protein environment.
Proteins produced by pure synthetic means are used in immunotherapy and treat autoimmune diseases. While the typical method failed to modify proteins very specifically, synthetic chemistry allows fine-tuning of the product.
Synthesizing calcium-based MOF from eggshell and PET plastic bottles link
Researchers reported the simple yet successful synthesis of calcium-based metal-organic framework (MOF) by shaking eggshell and benzene-1,4-dicarboxylate (BDC) obtained by hydrolysis of PET (polyethylene terephthalate) plastic bottles. Calcium-based MOFs were reported to perform satisfactorily in separating gases and alkanes in other studies. It is also a potential candidate in biological applications due to its biocompatibility and low toxicity.
Leaf-inspired material moves liquids with different surface tensions to opposite directions link
A synthetic material that resembles the ratcheted and spiralized leaves of the araucaria plant was fabricated by 3D printing. It is reported that ethanol and water were always directed towards opposite directions along the branch simultaneously when poured on the surface like on the real araucaria plant because of capillary actions and intermolecular forces.