There has been significant interest in converting gas, in particular CH₄, into liquids (gas to liquid (GTL)) (1). Nowadays, two main GTL processes are used: (a) syngas production followed by Fischer-Tropsch (FT) synthesis (2, 3); and (b) liquified natural gas (LNG) (4, 5). However, these processes require huge investments and their economic viability generally requires them to be carried out at very large scale (6), preferably exceeding 1000 tonnes per year. Therefore, they are mainly employed when low priced natural gas is available, typically in large quantities. As of today, the interest in exploiting small reservoirs has increased significantly, particularly because the gas from such reservoirs is often simply burnt as no other conversion technologies are available or commercially viable. On the other hand, interest in biomass and waste conversion (7) is increasing and this will require processes that are economically viable at small scale.

The development of small GTL plants based on FT is already happening with the use of microreactors and improved catalysts (6). On the other hand, efforts in finding new ways of producing liquids from gas are continuing. An example is the direct production of ethylene from CH₄ by oxidative coupling (8–10). Ethylene is one of the largest-volume petrochemicals and the building block for a vast range of chemicals from plastics to antifreeze solutions and solvents (11). Ethylene is currently mainly obtained from energy-intensive steam cracking of a wide range of hydrocarbon feedstocks.

OCM was first investigated in the early 1980s by Keller and Bhasin (12). In 1985, Lunsford (2) showed that, starting from CH₄, lithium/magnesium oxide (Li/MgO) could give a 19% yield for C₂, with ethylene as the main C₂ species. Since then, many catalyst combinations have been investigated for OCM with the highest obtained C₂ yields in the range 25–30% (13, 14). The most common catalyst formulations have been oxides based on alkaline earth metals doped with alkali metals and rare earth metals doped with alkali or alkaline earth metals (3). Several studies have shown that the activity of the OCM catalyst is affected by catalyst structural properties, such as morphology (15, 16). Also basicity and oxygen ion conductivity, which have been identified as key parameters for this reaction, are influenced by catalyst structural properties, such as particle size (17–19).

In parallel to catalyst development and considering the challenges encountered in finding catalysts able to perform OCM economically, efforts have recently been directed to the reactor design. There have been a number of different approaches to novel reactor design, the common factor being the use of membranes. In particular, for OCM, the use of membranes has been of interest because of its perceived ability to control the oxygen concentration in the gas phase and, therefore, decrease the undesired over oxidation (20, 21). Johnson Matthey has been involved recently in four European projects working in OCM: CAtalytic membrane REactors based on New mAterials for C₁–C₄ valorization (CARENA), MEthane activation via integrated MEmbrane REactors (MEMERE), Adaptable Reactors for Resource- and Energy-Efficient Methane Valorisation (ADREM) and Oxidative Coupling of Methane followed by Oligomerization to Liquids (OCMOL). The first two, CARENA and MEMERE, have been dealing with the use of membranes for this reaction. CARENA, a four-year Seventh Framework Programme for Research and Technological Development (FP7) carried out between 2011 and 2015, aimed at investigating the use of relevant process intensification and catalytic membrane reactors to transform light alkanes (C₁–C₄) and CO₂ to added-value products. Currently running is MEMERE, a four-year EU Horizon 2020 project that started in 2015 aimed at the conversion of CH₄ to ethylene using a membrane reactor with integrated air separation. Additionally, the use of non-thermal plasma reactors is also being evaluated for OCM (22, 23). ADREM, a four-year EU Horizon 2020 project, is looking at using innovative reactor types for CH₄ activation processes including a plasma reactor for OCM.

OCMOL, a five-year FP7 project, aimed to integrate energetic coupling of OCM and CO₂ reforming in a heat exchange reactor that was used to recycle CO₂ produced by the OCM reaction. The integration of OCM with other well-known processes to produce fuels or chemicals is another interesting approach and, indeed, this integration seems to be more important than the actual catalyst performance. A new follow up project, Methane oxidative conversion and hydroformylation to propylene (C123), has recently started and will be looking at transforming CH₄ into C₃ products via OCM which will simultaneously provide an optimum ratio of ethylene, carbon monoxide and hydrogen for its further hydroformylation into propanal or propanol. Ultimately, propanol can be dehydrated into propylene; either by an integrated approach as part of the hydroformylation step or through a stand-alone approach. Siluria Technologies, Inc, USA is promoting a catalytic process that can transform natural or shale gas into transportation fuels and commodity chemicals in an efficient, cost effective, scalable manner using processes that can be seamlessly integrated into existing industry infrastructure. This process is based around two basic chemistries: OCM and ethylene to liquids. In particular, nanowires are used for the OCM reaction.

Although process integration and reactor design were key for the OCMOL project, understanding on how to improve the catalyst performance to obtain higher selectivity towards ethylene and higher CH₄ conversion is still relevant as this will positively impact the process economics. The activity of the materials for OCM is closely related to their properties and it is well known that different properties are expected when comparing nanoparticles against the bulk material (24). Indeed, preliminary work has shown that nanomaterials with different morphologies could enhance the OCM performance at low temperatures (19). The present paper presents a summary of the work carried out within OCMOL around process integration and more particularly elaborates on the systematic study of the use of differently sized La-based nanoparticles for OCM which was a main focus of the catalyst development work in OCMOL carried out by Johnson Matthey. Flame spray pyrolysis (FSP) and microemulsion were the two methods investigated to produce La-based nanoparticles and results from the latter method will be presented and compared to data previously reported on the materials prepared by FSP (25).

2.1. The Process

2.2. Oxidative Coupling of Methane – Lanthanum-Based Nanoparticles

3.1. Experimental

The use of different synthesis temperatures during stage two had no effect on the phase obtained, LaNO₃(OH)₂·H₂O (see Figure S1 in the Supplementary Information). This phase differs from the ones obtained using FSP, in which La₂O₃ and carbonates were formed. Therefore, the samples produced via microemulsion needed an extra thermal treatment to obtain the active phases (stage three). Although no change was observed with respect to the phase composition, the crystallinity of the samples was affected by the synthesis temperature as can be seen in Table I. The results are in accordance with the surface areas which decrease with the increase in synthesis temperature in the range from 25°C to 60°C. The temperature has been reported to exhibit an effect on the micelle formation, i.e., higher temperatures reduce the interfacial tension between the oil and water which enhances the diffusion of the water into the oil phase and increases the number of smaller sized droplets (52, 53). Therefore, when increasing the temperature, a decrease in particle size would be expected, however, the opposite effect was observed which can be attributed to the particles not being single crystals. The particles are constituted of multiple diffraction domains with different orientations and the temperature might help the growth of these domains (Figure 3).

Fig. 3.

The samples produced by modifying the W:S ratio were also shown to be poorly crystalline materials when studied in stage two and also consisted of LaNO₃(OH)₂·H₂O (see Figure S2 in the Supplementary Information). The crystallite size increased with W:S, as determined by XRD (Table II). The surface area measured agreed with this observation. This effect can be logically explained because, when higher amounts of water are used (higher W:S ratio), bigger micelles are created. Indeed the effect of the W:S ratio has been shown in previous reported work to be one of the most defining synthesis variables for the particle size in microemulsion (48, 54). An example of this effect is described by Lisiecki et al. (55). These authors investigated the effect of the W:S ratio on the preparation of colloidal copper particles which were achieved using sodium bis(2-ethylhexyl)sulfosuccinate (AOT) as a surfactant, isooctane or cyclohexane as the solvents and an aqueous solution of hydrazine to reduce the Cu. The increase in particle size when increasing W:S ratio could be observed for the two different solvents.

The morphology of the materials obtained by microemulsion was very different from that obtained using FSP. The latter produced sphere like materials between 10–40 nm, while aggregates ranging from around 0.1 μm to 10 μm were observed for the samples prepared by microemulsion (Figure 4). These were shown to be flakes or needle like materials with different shapes which was confirmed by tilting the sample at different angles (Figure 5). This shape could be due to either aggregation after surfactant removal or it could be due to the colloidal nature of the synthesis mixture and the ability for these systems to form other shapes (56, 57).

Fig. 4.

Fig. 5.

To determine the origin of the flake or needle like morphology dynamic light scattering (DLS) analysis was performed on the microemulsions with and without the La precursor in the stage one at the W:S ratios used previously. The micelle size determined with DLS for the microemulsions without the La precursor in stage one followed the same trend observed previously for the materials obtained in stage two (Table II and Table III). A decrease of the W:S ratio resulted in an increase of micelle size. Unfortunately, the microemulsions containing the La precursor (stage one) could not be analysed with the Malvern Panalytical Zetasizer Nano ZS. This was due to the microemulsion becoming cloudy with the presence of the La precursor and not allowing the light to travel through the cuvette. The microemulsions were shown to be stable over time. Therefore, the flake or needle like morphology might be due to a non-spherical micelle shape. Although, the aggregation of spheres due to low stability of the nanoparticles once removed from the microemulsion cannot be eliminated.

As already mentioned, the samples prepared using microemulsion needed an extra thermal treatment to obtain the active phase for OCM, La₂O₃ and carbonate. Therefore, the effect of the thermal treatment on these samples to transform them into stage three materials was investigated using in situ XRD on the samples ME-T25 and ME-T60 (Figure 6 and Figure 7) as they represent the extremes of the crystallite sizes obtained for these materials. In this analysis, the evolution of phase and crystallite size was monitored during thermal treatment under two different atmospheres, air and N₂. The starting phase for both samples was different. While both contained LaNO₃(OH)₂^•H₂O, ME-T60 also contained La₂(OH)₃. The order of appearance of the phases was the same for the two samples, i.e., La(OH)₂NO₃, unassigned phase, Type Ia La₂O₂CO₃ and La₂O₃. The unassigned phase was determined to be constituted of a mixture of carbonates and nitrates as a loss of CO₂ and NO was observed at 340°C using mass spectrometry-thermogravimetric analysis (MS-TGA). The temperature at which each of these phases appeared depended on the starting sample and atmosphere. Not only the transition temperature between phases was different between the two samples, ME-T25 and ME-T60, but also the evolution of the crystallite size was different. These results showed that the systems are complex and further experiments should be done to understand the effect of the thermal treatment.

Fig. 6.

Fig. 7.

3.3. Oxidative Coupling of Methane Kinetics Performance

Synthesis of La-based nanomaterials using the microemulsion technique yielded flake like materials which contained nanocrystallites. The synthesis temperature has the most pronounced effect on the ultimate material properties. A minimum crystallite size was observed at 25°C, however this did not affect the final OCM activity. Other phenomena such as those occurring during the thermal treatment play an important role for the catalyst activity for these materials.

In situ XRD analysis demonstrated that the materials exhibit significant changes when submitted to thermal treatment to yield the final, catalytically active materials. The changes were difficult to control, rendering the microemulsion synthesis method a challenging one to produce La nanoparticles in a reproducible manner. Alternative techniques, such as FSP, seem much more promising in this respect. In terms of OCM activity, the presence of La carbonates in the materials used was crucial. This work has put in evidence the challenges encountered when trying to study the material properties, such as phase, particle size and morphology, independently from each other.

Optimisation of the OCM catalyst is a challenge and we believe the solution to achieve natural gas valorisation in an economically viable manner would be a process that integrates OCM. An example is the European project currently running, C123.

Carbon in its oxide and hydrocarbon forms is the cause of the energy and transport sectors’ biggest headache: climate change, so it is fitting that allotropes of this most versatile element look so promising to play a part in the modernisation of energy conversion. Naotoshi Nakashima (Kyushu University, Japan) brings together a collection of chapters showcasing some impressively creative nanoscience, predominantly from Japan, as part of Springer’s Nanostructure Science and Technology series. On reading, one is left with the impression that these fascinating materials will surely play some part in the coming decarbonisation of the economy.

Nanocarbons, as the name implies, are the allotropes of carbon that take the form of molecules of nanometre dimensions. The archetypal nanocarbon is graphene – a single layer of sp² hybridised atoms arranged in a two-dimensional hexagonal lattice. Nanotubes are essentially rolled up sheets of graphene, while fullerenes are essentially graphene sheets curled up into spheroids. Other nanoscale carbons, such as nanoporous carbon, carbon black and carbon foams are also discussed.

A large portion of the book is dedicated to the role of nanocarbons in fuel cells (FCs), so it is worth giving a brief overview of FCs and the associated functions of nanocarbons. FCs share features with both internal combustion engines and batteries. Like an internal combustion engine fuel is oxidised, producing exhaust gas, and like a battery chemical energy is converted to electrical energy. In the case of the popular proton exchange membrane fuel cells (PEMFCs) the fuel is commonly hydrogen, which is split into protons and electrons at the anode. Electrons are forced to flow through an external circuit because the electrodes are separated by an electrically insulating proton conducting polymer membrane such as Nafion^TM. Protons move through the membrane to the cathode where they react with oxygen and electrons that have travelled through the external circuit to form water. The overall reaction is the oxidation of H₂ to H₂O.

FC performance is largely determined by materials performance. Looking in more detail, at the anode side H₂ diffuses through the gas diffusion layer (GDL) to reach the catalyst. The GDL is often composed of carbon fibres which allow electrons to flow from the catalyst to the current collector and H₂ to diffuse between them to the catalyst. Platinum nanoparticles catalyse the splitting of H₂ into protons which are transported across the proton exchange membrane to the cathode and electrons which are transported along carbon fibres to the current collector.

Fig. 1.

Carbons are crucial to the performance and cost effectiveness of FCs, especially as catalyst supports where their high specific surface area enables a low Pt loading for a given power density and their conductivity provides a pathway for electrons to move between the Pt catalyst and the conducting fibres. FC performance can be greatly enhanced by improving the surface properties of nanocarbons for better gas accessibility and distribution of Pt nanoparticles. Their conductivity has a significant effect on power density and their chemical and thermal stability has a large influence on FC durability.

On the topic of FCs, some particularly interesting work on multiwalled carbon nanotubes (MWCNTs) as catalyst supports for H₂ PEMFCs by Naotoshi Nakashima and Tsuyohiko Fujigaya of Kyushu University, Japan, can be found in Chapter 1. The authors first address the difficulty of dispersing Pt nanoparticles onto nanotubes due to the lack of binding sites for deposition. Oxidation of the nanotubes is one method of introducing hydrophilic groups for binding, however this reduces the nanotubes’ electrochemical stability. To get around this problem the authors present a protocol for wrapping MWCNTs with conjugated polymers which bind to the nanotube surface through Π–Π interactions and on top of which the Pt catalyst can be more easily deposited. Chapter 1 also features durability tests of membrane electrode assemblies (MEAs) using polymer wrapped nanotubes as compared to polymer wrapped carbon black. Nanotube MEAs are found to maintain a significantly higher activity after several thousand cycles of durability tests compared to carbon blacks due to the inherent structural stability of the polymer wrapped pristine nanotubes.

Fig. 2.

Chapter 2, which is also written by Nakashima, follows on nicely from the first, exploring polymer wrapped nanotubes as catalyst supports for direct methanol FCs. A significant problem for direct methanol PEMFCs is methanol crossover where methanol diffuses through the Nafion^TM membrane to the cathode where it reacts with O₂, poisoning the Pt catalyst. While alternative transition metal cathode catalysts are more methanol resistant because they suppress its oxidation this is counterbalanced by lower oxygen reduction reaction (ORR) activities than Pt. Nakashima presents a solution to this problem by coating the polymer wrapped Pt decorated nanotubes with an outer layer of poly(vinylphosphonic acid) (PVPA) polymer, which increases methanol tolerance by the proposed mechanism of preferentially blocking diffusion of the larger molecule while only slightly reducing O₂ accessibility. The PVPA is also found to reduce carbon corrosion of nanotube and carbon black catalyst supports.

Another highlight on the topic of FCs is the review by Matsuhiko Nishizawa of Tohoku University, Japan, of carbon nanotube (CNT) based enzymatic biofuel cells in Chapter 15. Enzymatic biofuel cells are FCs in which an enzyme takes the place of Pt nanoparticles as the electrocatalyst. At the anode, the enzyme oxidises fuels such as fructose or glucose and generates electrons that are carried to the current collector by a conducting carbon support. At the cathode O₂ is reduced to H₂O by another enzyme. An advantage of biofuel cells is that the incredibly high selectivity of the enzyme means impure fuel feeds can be used and there is no need for a separator, making the overall design simply a pair of enzyme functionalised electrodes exposed to solutions containing fuel and O₂. The simplicity of the design makes them suitable for miniaturisation for use in implantable electronic devices. CNTs are presented as promising enzyme support materials due to their biocompatibility and high specific surface area. Previous attempts to immobilise enzymes onto nanotube electrode structures have created nanostructure films before enzyme modification. However, Nishizawa reports a method by which enzyme modification precedes film production so that the nanotubes pack ideally around the enzymes. This is achieved by adding an enzyme solution to a CNT forest which shrinks to a near hexagonal close packed structure on drying, entrapping the enzymes between the nanotubes and resulting in superior activity compared to previous production methods.

A fantastic piece of FC material characterisation work is presented in Chapter 5 by Somaye Rasouli and Paulo J. Ferreira working at the University of Texas at Austin, USA. They describe the technique of identical location transmission electron microscopy (TEM) as a way to understand the mechanism of Pt nanoparticle growth on CNTs in PEMFCs. One of the main causes of performance decline of PEMFCs is the instability and coarsening of Pt nanoparticles on carbon supports, which reduces the total surface area of active catalyst. The authors proposed four possible mechanisms of coarsening: Ostwald ripening, particle migration on the carbon support and coalescence, particle detachment and particle dissolution and reprecipitation. While the ideal way to investigate the mechanism would be to do in situ TEM and concurrent voltage cycling on a MEA, the release of moisture into the vacuum chamber precludes this. Furthermore, accelerated stress tests on MEAs make it difficult to tease apart the contribution to performance decline from different components. In order to study specifically Pt nanoparticle instability Arenz et al. first deposited the nanotube supported catalyst onto a gold TEM grid, initially observed the foil to define an area of interest, cycled the grid in a three-electrode electrochemical cell and then re-characterised the identical area of interest by TEM. It was found that carbon corrosion of nanotubes in voltage cycling in which carbon is lost as carbon dioxide, converting the hexagonal lattice to heptagon and pentagon rings, causes the Pt nanoparticles to move across the nanotube surface, possibly to reduce interfacial energy. As the nanoparticles move on the nanotubes they make contact with each other before coalescing to form larger particles.

Aptly, the complementary theme of the role of nanocarbons in H₂ production is explored in Chapters 9 and 19. In Chapter 9 Yutaka Takaguchi and Tomoyuki Tajima of Okayama University, Japan and Hideaki Miyake of Yamaguchi University, Japan, describe a new category of H₂ evolving photocatalysts based on semiconducting single walled carbon nanotubes (s-SWCNTs). Nanotubes can be metallic or semiconducting, i.e. have or not have a band gap, depending on the rolling angle between the axis of the tube and the crystallographic directions of the rolled graphene sheet. The productivity of H₂ from photocatalysts can be improved by expanding the range of active wavelengths from ultraviolet to near infrared (IR). The new category of nanotube based photocatalyst reported promisingly shows H₂ evolution under near IR radiation. However, s-SWCNTs are seldom used for this application due to the high exciton (electron-hole pair) dissociation energy, the fact that nanotubes form bundles that allow excitons to be transferred between tubes and also because they are difficult to disperse in H₂O. These problems are addressed rather ingeniously through the fabrication of a coaxial cable composed of an s-SWCNT covered with a layer of C₆₀ fullerenes, which are themselves functionalised with a hydrophilic dendron moiety which readily complexes with Pt, the cocatalyst for H₂ evolution. The cable is made simply by sonicating the nanotubes in a H₂O solution of the amphiphilic fullerodendron, which self assembles around the nanotubes due to Π–Π interactions. This hydrophilic dendron moiety makes the nanotubes more easily dispersible in H₂O, while the nanotube-C₆₀ heterojunction formed improves exciton dissociation. Furthermore, the problem of bundle formation is resolved by the isolation of the nanotubes from each other.

The FC’s biggest competitor in the race to decarbonise transport – the lithium-ion battery – may also benefit from the use of nanocarbons in future. Of particular interest is the review of nanocarbons as alternatives to graphite in anode materials written by Seok-Kyu Cho and Sang-Young Lee of Ulsan National Institute of Science and Technology (UNIST), South Korea and JongTae Yoo of Korea Institute of S&T Evaluation and Planning (KISTEP), South Korea in Chapter 18. The main advantage of these materials is that they could potentially have significantly higher Li capacities than graphite. For example, the capacity of C₆₀ fullerenes was shown by Armand et al. to be 12 Li atoms per fullerene. However, this was only realised once the problem of reduced C₆₀ dissolving in liquid electrolyte was worked around by substituting for a polyethylene oxide-based gel polymer electrolyte. Theoretical calculations of the Li storage potential of nanotubes show them to have capacities much greater than graphite, however these have yet to be realised experimentally. The authors conclude that the gap between theory and experiment motivates more work to better understand the lithiation mechanism of nanotubes.

The book covers the potential roles of nanocarbons in several aspects of the future decarbonised economy, covering power generation from H₂ and production of H₂. Chapter 20 covers the applications of nanotubes in grid energy generation from solar cells with an emphasis on CNT-silicon solar cells and CNT based perovskite solar cells. Feijiu Wang and Kazunari Matsuda of Kyoto University, Japan and Nagoya University, Japan provide a clear overview of the general principles of solar cells, which nicely sets the context for the chapter. Perhaps most intriguing is the ability of semiconducting SWCNTs to generate multiple excitons from one photon, meaning they may be able to surpass the Shockley-Queisser limit on the maximum efficiency of single junction solar cells, which assumes one exciton per photon. While there are many applications for nanotubes, from hole transport layers to transparent conducting electrodes, the authors point to a significant barrier to commercialisation: the presence of metallic nanotubes in the mixtures used for studies, which increase contact resistance due to their difference in work function and band gap.

This book covers a very broad range of applications for nanocarbons and while much of the underlying chemistry and materials science transfers between chapters, it is unlikely that any single reader would be familiar with all the concepts covered. The reviewer would recommend this book for any researchers working with carbon nanomaterials, particularly nanotubes, as well as researchers working with PEMFCs. Overall, an interesting read that reminds the reader of the impressive versatility and seemingly endless applications of carbon nanomaterials.

The TechConnect World Innovation Conference and Expo event has been held annually for the past 20 years and has alternated location between Boston, USA and California, USA. The 2019 conference was held in Boston between the 17th and 19th of June 2019 and attracted over 3000 participants from across all pillars of the ecosystem. The conference will be held in Washington DC, USA for the first time next year.

The aim of the conference is to connect top applied research and early-stage innovations from universities, laboratories and startups with industry end users and large corporates across the following themes, each with their own parallel stream:

There were also two poster sessions over the three days and a large exhibition space with over 250 exhibitors showcasing and demonstrating their novel technologies and inventions.

The keynote panel discussion ‘Inspiration to Innovation Commercialization of R&D’ took place on day one of the conference. The panel consisted of Alex Fensore (Sherwin-Williams, USA), Emily Riley (Energizer Holdings Inc, USA) and Chris van Buiten (Lockheed Martin, USA). There was discussion about needing both incremental and transformational innovation at different stages and in different places across an organisation and bespoke approaches and processes in place to run and manage each type effectively.

All panel members emphasised the importance of starting incremental innovation from capturing internal and customer unmet needs, followed by looking to see what capability is already in place or can be easily sourced to solve the problems and then collaborating externally to fill any gaps where necessary. There was less of a consensus on how to succeed at transformational or disruptive innovation.

The panel’s top tips for innovators were:

One of the highlights of each of the sessions was the Innovation Spotlight slot. During this time each of the sponsoring companies has an opportunity to pitch to the innovators in the room and describe the company, its vision, ethos and goals and especially the types of challenges they are facing and where they are looking for new advanced materials. The innovators in the audience found these slots particularly useful to guide the areas to target their future research. If an innovative solution can be matched with a known problem that a large company is facing, then the route to commercialisation for the technology can be made easier.

Then followed a number of seven minute selected pitches from university technology transfer offices or startups looking for seed funding, licensing partners or commercialisation partners. Among the pitches in the Advanced Materials Innovation Spotlight (sponsored by AGC, USA and Magna, USA) were a selection summarised here.

‘CompPair Technologies’, A. Cohades (Laboratory for Processing of Advanced Composites, EPFL, Switzerland) (1). Composite materials are formed by combining materials together to form an overall structure with properties that differ from those of the individual components. They are used for a wide range of applications from wind turbine blades or aircraft wings to boat hulls and masts, surfboards and buildings. High performance and lightweight composites that are composed of fibre and resin can be susceptible to damage by fatigue or exposure to dust or projectiles, even small impacts can cause microcracks, which leads to bigger cracks and potentially catastrophic part failure. CompPair has developed a ‘prepreg’: a fibre-based repair agent that is incorporated directly throughout the composite materials on production and remains dormant in the part until activated to enact self-repair of the composite. The healing process requires only moderate temperatures of 70–85°C, easily achieved with a hand-held heat source and takes only one minute. The incorporation of the repair agent uses existing manufacturing routes and assets, maintains the mechanical performance of the original material and can extend the equipment’s lifespan by up to three times. The company is looking to trial its repair additives in new composite materials.

‘Enabling New Technology for Anisotropic Conductive Films’, P. M. Lindberget, CondAlign, Norway. CondAlign has a patented technology for producing a range of conductive films with anisotropic properties known as anisotropic conductive films (ACFs). Anisotropic materials can be described as having directionally different material properties. For instance, the material can be insulating in one direction and electrically conductive in another. The films are usually comprised of conductive particles and a polymer matrix. The mechanical properties of the films are mainly given by the matrix, while the conductive properties are defined by the particles. An electric field is used to structure and align the filler particles in a liquid matrix (Figure 1). When applying the electric field, electric dipoles are induced in the particles causing chain formation. The alignment occurs due to electrophoresis, therefore it is also possible to align non-electrically conductive or magnetic particles. CondAlign has demonstrated production of films with a wide range of different parameters. It is demonstrated in roll to roll production, making the process scalable and cost effective. The process is material independent and is applicable to a wide range of applications.

Fig. 1.

‘Surface Coating for Reduction of Aerodynamic Noise and Vibrations’, C. Smith (Texas Tech University, USA). Flow separation is a phenomenon considered to be responsible for increased vibration and drag along with higher energy consumption in vehicles. The team at Texas Tech University have focused on solving this problem using passive control via bio-inspired surfaces. Using a material analogous to the denticles on a shark’s skin, they have developed a passive microscale fibrillar coating that significantly reduced flow separation. This micro-texture energises the fluid adjacent to the body by creating local suction and blowing, delaying separation and giving a smaller wake leading to reduced noise and vibrations. A feature of shark denticles is the asymmetric geometry (Figure 2) (2). The denticles are created initially through a process of etching and casting, however once a mould is made it can be used almost indefinitely allowing for cost-effective scale up. Initially focusing on wind turbine blades, they managed to achieve 30% drag and noise reduction and are looking for partners to co-develop solutions for specific applications where noise and vibration reduction are important.

Fig. 2.

‘Polyethylene Terephthalate (PET) Aerogels’, G. Wee (National University of Singapore (NUS)) (3). With much in the news currently about plastic waste, the team at NUS has created a cost-effective approach to fabricating recycled polyethylene terephthalate (rPET) aerogels from waste PET fibres obtained from plastic bottles. The high surface area rPET aerogels were fabricated through hydrogen and ester bonds formed between polyvinyl alcohol (PVA) and the rPET fibres and acetal bridges from a glutaraldehyde (GA) cross-linker. The rPET fibres were fully immersed in sodium hydroxide (NaOH) solution to produce carboxyl and hydroxyl groups on their surface. This was heated in an oven for 1 h at 80°C to accelerate the hydrolysis process. They were washed thoroughly with deionised (DI) water to remove all the remaining NaOH before immersing them into the mixture of PVA, GA and DI water. The pH of the reaction media was controlled at pH 3 by hydrochloric acid (37%) to accelerate the cross-linking reaction. The resulting mixture was sonicated for 30 min at 220–230 W for homogenisation and removal of bubbles. The cross-linking reaction was carried out in the oven for 3 h at 80°C and then placed into a freezer for 6–8 h until the sample was frozen. The frozen sample was placed into the freeze dryer for 48 h to remove all the solvent and produce the rPET aerogel. Full details can be found in their publication (4). The GA cross-linker can improve the interactions between the rPET fibres and the PVA cross-linker. It also reinforces the rPET-PVA fibre matrix by improving its stability and mechanical properties during the curing process (Figure 3). The aerogels are very versatile and can be given different surface treatments to customise them for different applications. For example when the surface contains terminal methyl groups, the aerogels can absorb large amounts of hydrocarbons very quickly making them highly suitable for oil spill cleaning. When the surface is coated with an amine group the material can absorb carbon dioxide from the environment. The surface chemistry can be adapted to be able to incorporate the aerogels into lightweight, breathable personal masks that filter out pollutants such as nitrogen oxides and carbon monoxide in places where air quality is of concern. Aerogels also have incredibly poor heat transfer properties, which makes them ideal for using as insulation. When coated with fire retardant chemicals, the material can withstand temperatures of up to 450°C but weighs only about 10% of the weight of traditional thermal lining, this would allow safety equipment such as coats for firefighters to be made much lighter, safer and cheaper and at the same time helping in the global fight against plastic waste.

Fig. 3.

Each year the TechConnect Review Panel identifies and ranks the top 15% of submitted technologies based on the potential positive impact the submitted technology will have on a specific industry sector. Some of the 2019 award winners are listed below.

Click Materials Corp, Canada, is expert in thin film technologies for coating highly efficient catalysts for reduced power consumption and smart glass. It is commercialising electrochromic window technology that is expected to be >50% lower cost than incumbent technologies. Smart windows provide variable tinting capabilities that significantly reduce energy requirements, improve employee productivity and enable the connected smart home.

Chemeleon, USA, is developing a platform technology for a novel chemical sensor with high sensitivity and specificity. The initial application includes a smart colorimetric sensor that can be embedded in drinkware to help consumers become aware of food and drink safety to protect them from date rape drug facilitated crime. It enables instantaneous on the spot detection of many other analytes such as volatile organic compound (VOC), explosives or nerve agents and it can also be extended to detect specific biomarkers to enable clinical diagnosis.

Inhibit Coatings Ltd, New Zealand, uses novel silver nanofunctionalisation to produce highly antimicrobial coatings. Silver is a well-known antimicrobial agent effective against over 650 different microorganisms. The novel nanotechnology allows very low biocide concentrations (<0.1%) and exhibits an extremely low leaching <0.1 ppb cm^–2 over a period of one week fully immersed. This low leach rate and biocide concentration gives rise to robust coatings with a very long antimicrobial lifetime that withstands wash cycles without compromising the physical properties of the resin system.

The overarching themes across all the streams of the conference were about making things better, smaller and cheaper but importantly also more safely, efficiently, ethically and sustainably: using greener solvents and processes, finding alternatives to conflicted starting materials and having a minimal impact on the world’s natural resources by considering recycling and cradle-to-cradle lifecycles at the start of the projects. This looks like a trend that is thankfully set to continue with many of the companies and institutions presenting referencing the United Nations Sustainable Development Goals in their drivers and business models.