Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:


New study presents hygroscopic micro/nanolenses along carbon nanotube ion channels


A novel technology, capable of analyzing nanomaterials in our daily lives with the use of common 'salt' has been developed. This allows various molecules to amplify up to hundreds of times the signals they produce in response to light, thereby making them very useful for nanomaterial research.

A research team, led by Professor Chang Young Lee in the School of Energy and Chemical Engineering at UNIST has introduced a novel technology, which allows carbon nanotubes (CNTs) to be easily observed under room temperature.

Formation of salt micro/nanocrystals along SWNTs via exterior transport.

Credit: UNIST

The coating of CNT surface with salt crystals allows direct observation of the shape and position changes of CNTs. Their findings also revealed that salt crystals made on CNTs could serve as a lens through which to observe nanomaterials.

Carbon nanotubes (CNTs), which are tube-like materials made of carbon atoms linked in hexagonal shapes, have recently attracted much attention due to their unique optical, mechanical, and electrical properties.

However, individual carbon nanotubes are difficult to observe with a general optical microscope because of their extremely small size. Although these objects on a very fine scale can be to examined via the electron microscope that uses a beam of electrons or the atomic force microscopy (AFM) that uses force between individual atoms, such methods are difficult to use and limit the observable area.

The team overcame these limitations by using salts commonly found in the environment. When salt water is added to carbon nanotubes arranged in one dimension and an electric field is applied, salt ions move along the carbon nanotube outer surface to form salt crystals.

These salt crystals, 'clothes', allow the observation of carbon nanotubes distributed over a large area using only the optical microscope commonly used in laboratories. Salt crystals dissolve well in water, which does not damage carbon nanotubes, and are stable before being washed out, so they can be semi-permanently visualized.

The team also found that salt crystals formed on carbon nanotubes can amplify the optical signals of carbon nanotubes by hundreds of times. Normally, when light receives, internal molecules interact with light energy to emit new signals, or optical signals.

Amplifying and analyzing this signal reveals the properties of the material, with salt crystals acting as a "lens" to amplify the optical signal. In fact, the team used the "salt lens" to easily find out the electrical properties and diameters of carbon nanotubes.

"The degree of optical signal amplification can be controlled by changing the refractive index according to the type of salt and the shape and size of the salt crystals," says Yun-Tae Kim in the School of Energy and Checmial Engineering at UNIST, the first author of the study.

The team went a step further by using a "salt lens" to move traces of glucose and urea molecules through the outer surface of the carbon nanotubes and detect them. The salt lens formed on the outer surface of the carbon nanotubes amplifies the optical signal to find a molecule containing one mole (M) of hundred diameters.

"The key to this technology is the ability to measure physical properties in real time without damaging nanomaterials at normal temperatures and pressures," says Professor Lee. "Our findings could be more widely applied to research of nanomaterials and nanophenomena."


Their study has been published and featured on the cover of the February 2020 edition of Nano Letters. Professor Jae-Hee Han from Gachon University also partook as a co-corresponding author of the study. Their work has been supported by the Basic Science Research Program and the Nano R&D Program through the National Research Foundation of Korea (NRF). Also, it has been supported by the Korea Institute of Energy Technology Evaluation and Planning (KETEP) and the Korean Ministry of Trade, Industry & Energy (MOTIE).

Media Contact

JooHyeon Heo

JooHyeon Heo | EurekAlert!
Further information:

More articles from Materials Sciences:

nachricht Oriented hexagonal boron nitride foster new type of information carrier
25.05.2020 | Japan Advanced Institute of Science and Technology

nachricht A replaceable, more efficient filter for N95 masks
22.05.2020 | American Chemical Society

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: I-call - When microimplants communicate with each other / Innovation driver digitization - "Smart Health“

Microelectronics as a key technology enables numerous innovations in the field of intelligent medical technology. The Fraunhofer Institute for Biomedical Engineering IBMT coordinates the BMBF cooperative project "I-call" realizing the first electronic system for ultrasound-based, safe and interference-resistant data transmission between implants in the human body.

When microelectronic systems are used for medical applications, they have to meet high requirements in terms of biocompatibility, reliability, energy...

Im Focus: When predictions of theoretical chemists become reality

Thomas Heine, Professor of Theoretical Chemistry at TU Dresden, together with his team, first predicted a topological 2D polymer in 2019. Only one year later, an international team led by Italian researchers was able to synthesize these materials and experimentally prove their topological properties. For the renowned journal Nature Materials, this was the occasion to invite Thomas Heine to a News and Views article, which was published this week. Under the title "Making 2D Topological Polymers a reality" Prof. Heine describes how his theory became a reality.

Ultrathin materials are extremely interesting as building blocks for next generation nano electronic devices, as it is much easier to make circuits and other...

Im Focus: Rolling into the deep

Scientists took a leukocyte as the blueprint and developed a microrobot that has the size, shape and moving capabilities of a white blood cell. Simulating a blood vessel in a laboratory setting, they succeeded in magnetically navigating the ball-shaped microroller through this dynamic and dense environment. The drug-delivery vehicle withstood the simulated blood flow, pushing the developments in targeted drug delivery a step further: inside the body, there is no better access route to all tissues and organs than the circulatory system. A robot that could actually travel through this finely woven web would revolutionize the minimally-invasive treatment of illnesses.

A team of scientists from the Max Planck Institute for Intelligent Systems (MPI-IS) in Stuttgart invented a tiny microrobot that resembles a white blood cell...

Im Focus: NASA's Curiosity rover finds clues to chilly ancient Mars buried in rocks

By studying the chemical elements on Mars today -- including carbon and oxygen -- scientists can work backwards to piece together the history of a planet that once had the conditions necessary to support life.

Weaving this story, element by element, from roughly 140 million miles (225 million kilometers) away is a painstaking process. But scientists aren't the type...

Im Focus: Making quantum 'waves' in ultrathin materials

Study co-led by Berkeley Lab reveals how wavelike plasmons could power up a new class of sensing and photochemical technologies at the nanoscale

Wavelike, collective oscillations of electrons known as "plasmons" are very important for determining the optical and electronic properties of metals.

All Focus news of the innovation-report >>>



Industry & Economy
Event News

Dresden Nexus Conference 2020: Same Time, Virtual Format, Registration Opened

19.05.2020 | Event News

Aachen Machine Tool Colloquium AWK'21 will take place on June 10 and 11, 2021

07.04.2020 | Event News

International Coral Reef Symposium in Bremen Postponed by a Year

06.04.2020 | Event News

Latest News

Inexpensive retinal diagnostics via smartphone

25.05.2020 | Medical Engineering

Smart machine maintenance: New AI system also detects unknown faults

25.05.2020 | Information Technology

Artificial Intelligence for optimized mobile communication

25.05.2020 | Information Technology

Science & Research
Overview of more VideoLinks >>>