Nanosheet-based electronics could be one drop away

Nanowerk  January 8, 2021 Researchers in Japan overcame the “coffee ring” effect of drop casting by controlled convection using a pipette and a hotplate. They found that dropping a solution containing 2D nanosheets with a simple pipette onto a substrate heated on a hotplate to a temperature of about 100°C, followed by removal of the solution, causes the nanosheets to come together in about 30 seconds to form a tile-like layer. They demonstrated controlled thermal convection by depositing particle solutions of titanium dioxide, calcium niobate, ruthenium oxide, and graphene oxide. They also tried different sizes and shapes of a variety […]

On-surface synthesis of graphene nanoribbons could advance quantum devices

Nanowerk  October 26, 2020 The lack of atomic-scale precision in using current state-of-the-art “top-down” synthetic methods — cutting a graphene sheet into atom-narrow strips – stymie graphene’s practical use. An international team of researchers (USA – Oak Ridge National Laboratory, The University of Tennessee, Poland, Luxembourg) has developed a “bottom-up” approach — building the graphene nanoribbon directly at the atomic level in such a way that it can be used in specific applications. The nanoribbons were synthesized on the surface of rutile titanium dioxide that assisted the cyclode-hydrofluorination of specifically designed precursor molecules through a series of thermally triggered transformations. […]

‘Like a fishing net,’ nanonet collapses to trap drug molecules

Science Daily  October 5, 2020 Natural biomolecules such as peptides and DNA can dynamically self-organize into diverse hierarchical structures. Researchers at the Northwestern University have reported both experiments and simulations on the dynamic network self-assembly and subsequent collapse of the synthetic homopolymer poly(propylene sulfone). The assembly is directed by dynamic noncovalent sulfone–sulfone bonds that are susceptible to solvent polarity. The hydration history controls the homopolymer assembly into uniform nanostructured hydrogels of spherical, vesicular, or cylindrical morphologies. The electrostatic hydrogels achieve >95% encapsulation efficiency for hydrophilic small molecules and biologics. This system validates sulfone–sulfone bonding for dynamic self-assembly, presenting a robust […]

Researchers breaking new ground in materials science

Science Daily  May 20, 2020 An international team of researchers (Canada, Italy) demonstrated the fabrication of mesoscale ordered two-dimensional π-conjugated polymer kagome lattices with semiconducting properties. To make the material they combined a rigid azatriangulene precursor and a hot dosing approach, which favours molecular diffusion and eliminates voids in the network. These results open opportunities for the synthesis of two-dimensional π-conjugated polymer Dirac cone materials and their integration into devices. The integration of this system into a device (e.g. transistors) may lead to outstanding performances. The results will foster more studies on a wide range of two-dimensional conjugated polymers with […]

Making Materials Mimic Each Other

American Physical Society  May 6, 2020 Based on the 2017 research confirming that spectral mimicry is theoretically possible, an international team of researchers (USA – Tulane University, US Army Research Laboratory, UMass Boston, Louisiana State University, UK) proposed a new way to make one material behave like another by applying specially designed time-dependent fields such as laser pulse. They derived a field-free, nonlinear equation of motion for controlling the expectation value of an essentially arbitrary observable together with rigorous constraints that determine the limits of controllability. They discuss the experimental feasibility of implementing the control fields generated by this model…read […]

Energy researchers invent error-free catalysts  March 4, 2020 Catalytic enhancement of chemical reactions via heterogeneous materials occurs through stabilization of transition states at designed active sites. An international team of researchers (University of Minnesota, University of Delaware, UC Santa Barbara, UMass Amherst) designed a new class of catalysts that greatly accelerated the primary surface reactions using waves. When the applied wave frequency and amplitude match up with characteristics of the primary chemistry, the reaction becomes thousands of times faster than all other side reactions and essentially stops making any errors to side products. The researchers were able to broadly explain the relationship between different […]

Lights, camera, action… the super-fast world of droplet dynamics

Eurekalert  February 25, 2020 The chemistry behind emerging 3D-printing technologies involves having chemicals deposited onto a surface in a highly specific way. But how to make that happen in the printing process is poorly understood. Researchers in the UK used two synchronised cameras to see what was happening both on the surface and inside the droplets and to make a better assessment of mixing, whether they have mixed or has one droplet just passed over the other. The research provides understanding of the way chemicals react when they are deposited by a 3D printer which will lead to significant advances […]

Self-assembled artificial microtubules developed

Science Daily  January 17, 2020 Microtubule is one of the principal cellular components formed via hierarchical self‐assembly of nanometer‐sized tubulin heterodimers into protofilaments, which then associate to form a micron‐length‐scale, multi‐stranded tube. Researchers in South Korea discovered that a cucurbituril (pumpkin-shaped chemical compound)-based host-guest complex polymerized into a linear polymer chain, which was further associated with each other into a hollow microtubule via van der Waals interactions arising from their shape self-complementarity. It formed a tubular structure with a length over tens of micrometers. The polymer chain became straight and stiff by itself, and eventually LEGO brick-like shape emerged during […]

Light-based ‘tractor beam’ assembles materials at the nanoscale

Nanowerk  November 4, 2019 A team of researchers in the US (University of Washington, Pacific Northwest National Laboratory) adapted optical tweezers which act as a light-based “tractor beam” that can assemble nanoscale semiconductor materials precisely into larger structures. They demonstrated the technique by assembling a heterostructure starting with shorter nanorods of crystalline germanium and capped each with a metallic bismuth nanocrystal. As all the components are suspended in solution the size and shape of the nanostructure can be controlled as it is assembled. The process is repeated to assemble the structure to desired size. They believe that this nanosoldering approach […]