HKUtopia

Materials

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

 

From light-controlled small molecules to smart materials  link

Supramolecular polymers are a unique class of polymers that are held together by non-covalent interactions. Unlike traditional covalent polymers, supramolecular polymers can be easily disassembled and reassembled.

 

These materials have potential applications in smart materials with controllable functions. For example, light-driven soft actuators and light-triggered electronic devices. When exposed to light signals, those materials may change in structure, dipole, and chirality, and result in re-self-assembly. Photo-controllable supramolecular polymers are currently facing a wide range of challenges, like the photo-efficiency, hopefully, there will be further development such that materials are responsive in the future.

 

Nanomaterials: 3D printing of glass without sintering  link

A process to print nanometer-scale quartz glass structures directly onto semiconductor chips. A hybrid organic-inorganic polymer resin as feedstock material for 3D printing of silicon dioxide is synthesized, which is heated to 650°C in the air to remove organic components, the temperature required for this purpose is only half the temperature needed for processes based on the sintering of nanoparticles. The new process produces robust, optical-grade glass structures with excellent mechanical properties at far lower temperatures than conventional processes.

 

Application of cellulosic material for green electronics devices link

In today's world, there is insufficient of environmentally friendly material, therefore, sustainable materials have become very important. Cellulose is an abundant natural resource, is eco-friendly, and has numerous applications relevant to electronic devices due to its abundance in nature, high durability, structural strength, robustness, and flexibility. As the primary component of biomass, its source of origin, and its various chemical, mechanical, and combined treatments to produce cellulose-based materials such as cellulosic nanofiber (CNF), nanofibril cellulose (NFC), and cellulosic nanocrystals (CNC), and regenerated cellulose film (RCF). For example, a cellulosic-based translucent substrate made of microsized fibers has been synthesized to replace polyethylene terephthalate which is non-decomposable.

Graphene, Fullerene and their derivatives

 

Graphene and fullerene are two fascinating materials that have captured the attention of scientists and researchers around the world. Both materials have unique properties that make them highly desirable for a variety of applications, ranging from electronics and energy storage to medicine and environmental remediation.

 

Both graphene and fullerene have been the subject of intense research in recent years, as scientists seek to unlock their full potential. Researchers have discovered that graphene can be used to create multiple sensors and even flexible displays. Meanwhile, fullerene could be used to create more effective energy conversion and treat a wide range of illnesses.

 

As research continues, we will likely discover even more uses for these amazing materials, and they could play a vital role in shaping the future of technology, medicine, and science.

 

Recent research directions

 

Graphene as a C-reactive protein (CRP) sensor    link   video

C-reactive protein has a low concentration in human blood such that it is difficult to be monitored. Graphene with a large surface area and small pores that encapsulate redox molecules is used as a sensor. When gold nanoparticles bind to CRP pass through the graphene sensor via sweating. They bind to graphene molecules. Such binding causes the redox reaction that generates an electric current and is detected by the electronic component in the sensor.

 

Graphene oxide- a translator of sign language into audio   link

A sensor of graphene oxide powered internally by a moist electric generator is constructed. It contains a membrane such that water molecules from the air can bind to the surface. After absorbing water, positive and negative electric terminals are developed to detect the bio-electric signal from humans. Various finger movements and gestures generate a unique signal to the sensor, once the sensor reads the signal, it automatically translates the message to language. Through analyzing a wide range of signals, scientists hope it can even be applied in health measurement in the future.

 

Fullerene nanotube as surgery material   link

Fullerene like C60 has potential applications in microsurgery and nano-surgery due to its unique properties such as high strength, flexibility, and biocompatibility. They can be used as nanoscale surgical tools for precise cutting and manipulation of tissues and cells. C60 nanotubes can also be used as drug delivery vehicles, as they can easily penetrate cell membranes and deliver drugs directly to targeted cells. Additionally, they have been shown to have antioxidant and anti-inflammatory properties, which can aid in the healing process.

 

Fullerene-derivative interlayer for improved solar efficiency    link

Current perovskite solar cell does not have high efficiency in converting sunlight into electricity. New material contain fullerene, and its derivatives and other molecules help in addressing defects in the all-inorganic perovskite layer. Fullerene can act as an electron acceptor to increase the efficiency of the cell. Also, it can absorb a wide range of light wavelengths, including ultraviolet and visible light, making it useful in capturing a broader range of solar energy. Hence, energy conversion efficiency has risen thanks to the application of fullerene.

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.


Recent research directions

Plants transformed into detectors of dangerous chemicals     link      

A technology uses abscisic acid, a protein that helps plants adapt to environmental changes. When a plant is exposed to a certain chemical, its receptors bind to it, causing the plant to turn red. The technology is not yet commercially viable, but it could be used in environmental health or defense applications. The team also demonstrated the ability to turn yeast into a sensor, allowing for simultaneous reactions to two different chemicals. Although not commercially viable, the discovery opens up possibilities for applications in agriculture and the environment.


Exploring bio-inspired polymer coatings for aerospace advancements   link

Bio-inspired coatings improve the performance of aerospace materials in several ways. For example, Bio-inspired coatings that replicate the cooling mechanisms found in the skin of certain animals, such as polar bear fur or penguins, can enhance thermal management by assisting in heat dissipation and reducing thermal stress on critical components.


A new bio-inspired solar leaf design with increased harvesting efficiency   link

A new leaf-like solar energy design that could revolutionize renewable energy technologies. The photovoltaic leaf (PV-leaf) technology, inspired by nature, can generate over 10% more electricity than conventional solar panels, which can lose up to 70% of incoming energy to the environment. The design could also produce over 40 billion cubic metres of freshwater annually if deployed by 2050. It eliminates the need for pumps, fans, control units, and expensive materials, generates clean water and thermal energy, and adapts to ambient temperature and solar conditions.


Art with DNA – Digitally creating 16 million colors by chemistry   link

The process involves hybridizing small DNA strands linked to fluorescent molecules to a long complementary DNA strand create 16 million colors and accurately reproducing any digital image in DNA format. The stability of the duplex is lowered by carefully removing the bases of the DNA strand at pre-defined positions along the sequence. This results in 256 shades for all color channels, generating 16 million combinations and matching the color complexity of modern digital images. The researchers used maskless array synthesis to synthesize hundreds of thousands of unique DNA sequences simultaneously on a miniature rectangle the size of a fingernail. The reproduction process is applicable to 1080p and potentially 4K image resolution.