Graphene Oxide

PEDOT, short for poly(3,4-ethylenedioxythiophene), is a flexible, transparent film often applied to the surfaces of photographic films and electronic components to protect them from static electricity. It is also found in touch screens, organic solar cells and electrochromic devices, such as smart windows. However, PEDOT’s potential for energy storage has been limited because commercially available PEDOT materials lack the electrical conductivity and surface area needed to hold large amounts of energy.

An example of how EDOT monomer vapors react with a droplet of graphene oxide and ferric chloride to form PEDOT nanofibers. Image credit: UCLA

UCLA chemists have addressed these challenges with an innovative method that makes use of graphene oxide to control the morphology of PEDOT to grow nanofibers precisely. These nanofibers exhibit exceptional conductivity and expanded surface area, both of which are crucial for enhancing the energy storage capabilities of PEDOT. This approach demonstrates the potential of PEDOT nanofibers for supercapacitor applications.

Researchers at the National University of Singapore (NUS), and Deliarts recently presented an interdisciplinary approach combining materials science, ultrasonication, artistic expression, and curatorial practice to develop graphene-enhanced ceramics, improving strength and aesthetics. The focus of the approach was incorporating graphene oxide (GO) into kaolin clay and exploring its effects on material properties. 

Image taken from: technologynetworks.com, Credit: Daria Andreeva, National University of Singapore, and Delia Prvački, Deliarts Pte Ltd.

In recent years, scientists have been adding GO to ceramic slurries — consisting of particles of kaolin clay or other materials dispersed in water — to make fired ceramics more durable and resistant to thermal shock. The team adapted this technique by using ultrasound to better mix the GO into kaolin slurries. They adjusted GO concentration and ultrasound exposure time to find the conditions that most enhanced the resulting ceramics’ strength and heat resistance. The team also collaborated with artist-in-residence Delia Prvački, who created works from the new ceramic material that are on display at the National University of Singapore Museum. 

Researchers at the National University of Singapore, working with colleagues from Manchester University and Guangdong University of Technology, have developed a sponge-like material made of graphene oxide and chitosan, that can be used to extract gold from electronic waste. In their recent study, the research team describes how they made their sponge and how well it worked during testing.

Previous research has shown that removing gold, silver and other metals from electronic equipment that is no longer useful, as a way to recycle such materials, is a difficult task that often results in low yields and the generation of a variety of toxic pollutants. In this new work, the team has found a way to remove the gold in a way that is cheaper and cleaner than conventional methods and much more efficient as well.

Singapore-based Memsift Innovations has entered into a technology transfer agreement with Singapore’s Ngee Ann Polytechnic on an innovative graphene membrane technology.

It was explained that the technology, featuring graphene oxide-based hollow fiber ultrafiltration and nanofiltration membranes, was developed based on over a decade of research and development. The ultrafiltration technology utilizes a graphene oxide-block copolymer composite renowned for its exceptional chemical and thermal stability, making it ideal for harsh industrial applications. Its unique surface chemistry forms a protective water layer that effectively prevents fouling. The nanofiltration technology employs a robust single-layer modified graphene oxide membrane with synthetic water channels, enhancing selectivity and permeability. This enables efficient molecular-level separation and differentiation between monovalent and multivalent ions.

While graphene aerogels have advantageous properties like extremely low weight, high porosity and good electrical conductivity, engineers who tried to use them to develop pressure sensors have encountered some difficulties. 

Image credit: Nano Letters 2024

Specifically, many of these materials have an intrinsically stiff microstructure, which poses limits on their strain sensing capabilities. Researchers from Xi'an Jiaotong University, Northumbria University, UCLA, University of Alberta and other institutes recently introduced a new fabrication strategy for synthesizing aerogel metamaterials to overcome this limitation. This strategy fabricates a durable graphene oxide-based aerogel metamaterial that exhibits a remarkable sensitivity to human touch and motion.

A research team from Skoltech, MIPT, Emanuel Institute of Biochemical Physics of Russian Academy of
Sciences, and other scientific organizations recently conducted a study to determine which conditions are the most suitable for storing graphene oxide.

The results showed that the most optimal conditions for graphene oxide, when its properties will not change, are low temperatures and a lack of light. 

Researchers from Kumamoto University and Hiroshima University have announced a significant development in hydrogen ion barrier films using graphene oxide (GO) without internal pores. This approach could be beneficial for protective coatings for various applications.

In their study, the research team successfully synthesized and developed a pore-free GO (Pf-GO) membrane with controlled oxygen functional groups. Traditionally, GO has been known for its high ionic conductivity, which made it challenging to use as an ion barrier. However, by eliminating the internal pores, the team created a material with dramatically improved hydrogen ion barrier properties.

Researchers from Nagoya University, Osaka University and National Taiwan University recently developed a method for the high-speed, large-area deposition of two-dimensional (2D) materials, including oxides, graphene oxide, and boron nitride. This innovative technique, known as the "spontaneous integrated transfer method," was discovered by chance; however, it could significantly improve the production of nanosheets.

Traditionally, methods like chemical vapor deposition (CVD) and the Langmuir-Blodgett (LB) technique have been employed for nanosheet fabrication. However, these methods have significant disadvantages, including difficulties in achieving uniform, large-area deposition and complications in the substrate transfer process. Aiming to develop a more effective deposition technology, the research team discovered a fascinating phenomenon completely by chance: when nanosheets get wet, they spontaneously align themselves on the surface of water, forming dense films within a mere 15 seconds. This process, termed the "spontaneous spreading phenomenon," suggested a more effective deposition technology.

Chang Robotics, an engineering company, and Northwestern University’s INVO Lab have announced a joint venture aimed at reducing contamination from microplastics and poly-fluoroalkyl substances (PFAS) in the US food supply.  

This collaboration has led to the development of GOEco, an initiative that shows that very small amounts of graphene oxide can be infused into paper products or compostable packaging materials to replace plastic and PFAS. GOEco’s primary goal is to replace the widespread use of plastics in food packaging, such as paper plates and disposable utensils. The patent-pending technology helps enhance the environmental friendliness of disposable tableware without compromising functionality.

Researchers from Pacific Northwest National Laboratory have found that reducing graphene oxide (GO) membranes with ultraviolet (UV) light alters the oxygen functional groups on the GO surface. This modification results in a different, chromatography-like separation mechanism that is selective for charge rather than size.

Image credit: Chemical Engineering Journal

Developing efficient, selective, and scalable separations for critical materials, including lithium and magnesium, is essential to meeting the increasing demands for clean energy technologies and alleviating challenges with domestic supply chains. GO membranes have shown promise for separating ions from mixed solutions based on size.