Insights into hydrothermally altered oceanic crust through melt inclusion analysis using Linkam’s TS1500

There are many different types of Volcano. One is the so-called ‘ocean island’ volcanoes, which include Hawaii, Iceland, Samoa, Reunion, Tahiti. The magmatic sources of ocean island basalts are believed to be derived from the lower mantle. Mantle upwellings (part of convection within the mantle) carry deep mantle materials towards the surface, causing the materials to melt, generating these ocean island basalts. Geochemists study the material of ocean island basalts to elucidate their chemical composition and its evolution in the deep mantle. In the previous studies, it has been suggested that some ocean island basalts from Cook-Austral Islands (French Polynesia) involve subducted ancient oceanic crust in their magma sources.

Scientists from the Japan Agency for Marine-Earth Science and Technology, The University of Tokyo and Tokyo Institute of Technoloy explored the nature of volatiles in the mantle and the exchange of volatiles between the mantle and the Earth’s surface.

The major volatile reservoir in the Earth is the atmosphere and hydrosphere (Earth’s surface layer), but those volatiles came from the mantle by long-term degassing of the mantle. It is still unclear how much of these volatiles remain in the mantle and whether the exchange of volatiles occur between the Earth’s surface and the mantle, that is, outgassing from the mantle through volcanism and ingassing from the surface to the mantle via subduction of oceanic crust.

Their main finding was the exchange of Chlorine (Cl) between the Earth’s surface and the mantle. They measured volatile composition in olivine-hosted melt inclusions in ocean island basalts from Raivavae, Austral Islands. Due to the size of melt inclusions (50 to 150 micrometers in their samples), they combined several in-situ micro-analytical techniques to measure volatile elements (with secondary ion mass spectrometry) together with lithophile elements and Lead (Pb) isotopes (EPMA and LA-ICP-MS).

The Linkam TS1500 heating stage was used to homogenize melt inclusions. By using a heating stage and microscope, they were able to avoid overheating of the sample and confirm that melt inclusions did not crack or burst during the heating experiment. The implication of this work is that such subducted oceanic crust, which is eventually accumulated in the deep mantle, could be a major reservoir of Cl in the mantle. Their work suggested that subduction of oceanic crust played a significant role in moderating the salinity conditions in the ocean. Chlorine is one of the essential elements for life, but too much salinity is rather stressful. They concluded that the exchange of Cl (and volatiles) may play a key role in the evolution of life. This will be part of future studies

The group would like to expand their research target not only for ocean islands but also for island-arc volcanism, particularly in Japan where island-arc type volcanoes are prevalent. They plan to study volatiles in melt inclusions in island-arc magmas to understand how much volatiles exist before eruption and how the volatiles control the eruption style in each volcanic system. The Linkam TS1500 is essential in these studies.

Find out more here.

Hanyu et al., Tiny droplets of ocean island basalts unveil Earth’s deep chlorine cycle (2019). Nature Communicationsvolume 10, Article number: 60

E-skin: Understanding mechanical properties of flexible electronics

LTS420 shown above

Electronic skins (E-skins) that can mimic the functions of a human skin have been intensively studied in the past few years. They are expected to have a great impact on the upcoming generation of portable and wearable electronics related to the Internet of Things. Even after many breakthroughs in the material sciences, there are still difficulties in achieving high performance and highly functional sensors durable enough for continuous monitoring of human activity and health.

Advanced micro- and nanoscale materials within polymer-based protective layers have been successfully applied for the E-skins. However, it is not only important to study and understand the behavior and properties of these electronic materials, but also to create smart structures to achieve the desired performance for these devices.

A research group from University of Oulu in Finland bypassed common performance and functional issues by combining advanced materials and an ingenious structure to achieve mechanosensitivity to different stimuli, high sensing performance, and functionality within the device. The structure not only provided simultaneous ability to be adhered to a human skin or be attached to clothes or textiles, but also possibilities for precise tuning of the response to achieve optimal performances for different locations in the human body. The devices were able to record human activity and health in a reliable manner, providing adequate long-term durability with machine washability.

The group used a TST350, now superceeded by the LTS420 to test the tensile properties of their sample. When asked about the purpose of the stage, author Jarrko Tolvanen explained: “In our research the Linkam TST350 stage has provided a reliable way to record the stress-strain curve of various materials. Also, this stage has enabled easy and quick way of testing the mechanical properties under controllable temperature and humidity conditions, that could be proven advantageous when further improving and optimizing the performance of a strain sensor.”

Although more testing is required for long-term durability and environmental stability, the group’s work is a promising start in achieving high performance wearable sensors.

Read the research here

Exploring plasmon-actuated nano-asssembled microshells using a Linkam hotstage

LTS420 shown above

Nanomaterials have been found to have interesting electronic, magnetic and optical properties. They can manipulate electromagnetic fields through localised surface plasmon resonance to modulate light interactions. Such plasmonic phenomena are popular in application for the biomedical field. 

Researchers from the University of California, Merced and Stanford University in the USA developed a micro-scale delivery module for various organic and inorganic compounds using nanomaterials. 

Their aim was to create something that would be versatile and capable of encapsulating a range of different materials (drugs, dyes, cells, bacteria, etc.) for many different applications. These could include drug delivery for cancer treatment, releasing dyes in vivo for fluorescence imaging, or tissue engineering. The problem with existing platforms is that they are either leaky, unable to hold the contents without loss for any prolonged period, or they are incapable of releasing contents in a spatially and temporally controlled manner. For example, other cargo delivery systems that use light to activate the release of the cargo need several milliwatts of power over several minutes to achieve the required effect, therefore creating significant localised heating. The group managed to reduce the power required to less than 2 mW and the release time to under 5 seconds. As a result, the total temperature increase at the vicinity of the capsules is only to ~ 40°C, which is well within tolerable limits for many biological systems.

The team used an LTS350*,(now superseeded by the LTS420), for their experiments. When asked on the importance of the hotstage, Dr Ghosh said: “One of the most critical parameters that determine whether a cargo delivery system is viable in vivo is the thermal gradient that is produced because of the photothermal effect when optical excitation used to rupture the shells is in resonance with the plasmonic response of the nanoparticles that make up the shell walls. To estimate this, the first step was to use heat to rupture the shells instead of light. That is where we used the heating stage.”
 

Fluorescence microscopy images of a Nano-Assembled Microshell loaded with a fuorescent dye on the LTS350 stage. 

Their method has proved to be exciting and advantageous. No leakage was seen for over five months after encapsulation, promising a long shelf life. Furthermore, a lower optical intensity was required for shell disintegration compared to other methods. 

Although more work is required to improve future in-vivo applications (such as actuation by near infra-red and reducing overall size of capsule), their work is a promising result for future cargo delivery systems. 

Find out more about the research here

*The LTS350 has been superseded by the LTS420 offering a large temperature range and better temperature control to 0.01°C.
 

Investigating meniscus-assisted solution printing of large-grained perovskite film for high-efficiency solar cells

LTS420

Solution printing is a novel technique which uses an ink solution, containing semi-conductor precursors or nanoparticles, and deposits these on substrates with desirable characteristics. This offers a cost-effective method of creating large area thin film optoelectronics whilst also offering precise control over the stoichiometry and adaptability of the material. Metal halide perovskites have superb optoelectronic properties and the last few years has seen their power conversion efficiency increase rapidly, largely through the optimisation of the crystal morphology. 

The requirement to control morphology has posed a problem for solution printing. The understanding of crystallisation in dynamic flow of perovskite inks is quite limited, thus imposing restrictions in achieving high-quality perovskite films by the solution-printing technique.

A group from the Georgia Institute of Technology and the University of Nebraska-Lincoln in the USA used a meniscus-assisted solution printing method to elucidate the crystallisation kinetics of perovskite inks and help create high efficiency perovskite solar cells. The thin-films were created with preferred crystal orientation with micrometre-scale grains. 

When discussing their work Professor Lin said, “Through integrating the meniscus effect within the solution printing, we found that the solvent evaporation could be largely promoted by the meniscus effect instead of the thermal evaporation as in conventional doctor-blade coatings, thus leading to the low-temperature solution-based deposition of high-quality perovskite films with preferred crystal orientations. This low temperature feature circumvents thermal degradations and thermomechanical fatigues on perovskite and electrode materials, as well as decreases energy consumptions. Our technique paves the pathway for depositing perovskite thin films on flexible polymer substrates, and is anticipated to promote the future development and applications of perovskites in low-cost, large-area, and flexible optoelectronic devices.”

The group used an LTS350*, now superseded by the LTS420 to control the substrate temperature during the meniscus-assisted solution printing process, due to its capability of precisely controlling the temperature at ±0.1oC. Their investigation on the crystallisation kinetics of perovskite films revealed that a large temperature fluctuation would seriously impact the crystallisation kinetics of perovskite films during the meniscus-assisted printing process. The LTS350* was ideal for maintaining the substrate at a constant temperature and focusing on the exploration of the meniscus effect on the perovskite crystallisation process. 

Their study helped to uncover the crystallisation kinetics of perovskites during the printing process, providing rational guides to precisely control the crystallisation morphology of printed perovskite films. By improving the control over morphology, the group’s work helps to pave a route to large-area optoelectronic devices for commercial applications.

*The LTS350 has been superseded by the LTS420 offering a large temperature range and better temperature control to 0.01°C.

Read the research paper here