Researchers synthesize new liquid crystals a…

Researchers synthesize new liquid crystals allowing directed transmission of electricity

Liquid and solid—most people are unaware that there can be states in between. Liquid crystals are representative of one such state. While the molecules in liquids swim around at random, neighboring molecules in liquid crystals are aligned as in regular crystal grids, but the material is still liquid. Liquid crystals are thus an example of an intermediate state that is neither really solid nor really liquid¬¬. They flow like a liquid, and yet their molecules are grouped in small, regularly ordered units. A particular application of liquid crystals is optical imaging technology as in the screens of televisions, smartphones, and calculators. All LCD—or liquid crystal display—devices use these molecules.

Researchers at the Institute of Organic Chemistry at Johannes Gutenberg University Mainz (JGU) have synthesized novel liquid crystals in a project sponsored by the German Research Foundation (DFG). “If you slowly cool our liquid crystalline materials, the molecules align in a self-assembly process to form columns,” explained Professor Heiner Detert of JGU. “We can imagine these columns like piles of beer mats stacked one on top of the other. But the special thing is that these columns conduct electrical energy along their whole length.” The materials can thus serve as organic, liquid crystalline “power cables” and provide targeted electricity transmission in electronic components. While most materials conduct positive charges carried by holes, the new molecules actually conduct electrons. An additional advantage of a liquid crystalline power cable is that if it ruptures, any such rupture will heal entirely by itself.

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New Concept for Self-Assembling Mobile Micro…

New Concept for Self-Assembling Mobile Micromachines

In the future, designers of micromachines can utilize a new effect. A team led by researchers from the Max Planck Institute for Intelligent Systems in Stuttgart have presented a concept that enables the components of microvehicles, microrotors and micropumps to assemble themselves in an electric field. The new concept may help to construct medical microrobots for use in the human body or to fit laboratory devices on a microchip.

Approximately half the thickness of a human hair, microvehicles could in the future deliver drugs directly to the source of disease, help with diagnosis and take minimally invasive surgery to the next level. However, miniaturization is also of interest for medical, biological and chemical laboratories. With a laboratory on a microchip, medical or environmental chemistry analyses that currently require a room full of equipment could also be performed on the move.

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Quick liquid packaging: Encasing water silho…

Quick liquid packaging: Encasing water silhouettes in 3-D polymer membranes for lab-in-a-drop experiments

The ability to confine water in an enclosed compartment without directly manipulating it or using rigid containers is an attractive possibility. In a recent study, Sara Coppola and an interdisciplinary research team in the departments of Biomaterials, Intelligent systems, Industrial Production Engineering and Advanced Biomaterials for Healthcare in Italy, proposed a water-based, bottom-up approach to encase facile, short-lived water silhouettes in a custom-made adaptive suit.

In the work, they used a biocompatible polymer that could self-assemble with unprecedented degrees of freedom on the water surface to produce a thin membrane. They custom designed the polymer film as an external container of a liquid core or as a free-standing layer. The scientists characterized the physical properties and morphology of the membrane and proposed a variety of applications for the phenomenon from the nanoscale to the macroscale. The process could encapsulate cells or microorganisms successfully without harm, opening the way to a breakthrough approach applicable for organ-on-a-chip and lab-in-a-drop experiments. The results are now published in Science Advances.

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qingzinano: Nano-microfiber Composites For F…

qingzinano:

Nano-microfiber Composites For Filtration

Nanofibers prepared by molecular self-assembly are in general not self-supporting and therefore require stabilizing scaffold structures. In fact, a lot of research in the past has been done with supramolecular self-assembly of molecules forming a network of nanofibers used as organo/hydrogelators. But efforts to use them as a self-standing membrane or as free fibers were not strong. Therefore, the self-assembly of trisamides was also tried on a substrate, i.e., other microfiber nonwovens, leading to microenanofiber composites (Fig. 4.4) used for filtration (Weiss et al., 2016).

Multistep self-assembly opens door to new reco…

Multistep self-assembly opens door to new reconfigurable materials

Self-assembling synthetic materials come together when tiny, uniform building blocks interact and form a structure. However, nature lets materials like proteins of varying size and shape assemble, allowing for complex architectures that can handle multiple tasks.

[…]

University of Illinois engineers took a closer look at how nonuniform synthetic particles assemble and were surprised to find that it happens in multiples phases, opening the door for new reconfigurable materials for use in technologies such as solar cells and catalysis.

The findings are reported in the journal Nature Communications.

“Traditional self-assembly can be thought of like a grocery store stacking apples for a display in the produce section,” said Qian Chen, a professor of materials science and engineering and lead author of the new study. “They would need to work with similarly sized and shaped apples – or particles in the case of self-assembly – to make the structure sturdy.”

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New method inverts the self-assembly of liqu…

New method inverts the self-assembly of liquid crystals

In liquid crystals, molecules automatically arrange themselves in an ordered fashion. Researchers from the University of Luxembourg have discovered a method that allows an anti-ordered state, which will enable novel material properties and potentially new technical applications, such as artificial muscles for soft robotics. They published their findings in the scientific journal Science Advances.

The research team of Prof. Jan Lagerwall at the University of Luxembourg studies the characteristics of liquid crystals, which can be found in many areas ranging from cell membranes in the body to displays in many electronic devices. The material combines liquid-like mobility and flexibility and long-range order of its molecules; the latter is otherwise a typical feature of solid crystals. This gives rise to remarkable properties that render liquid crystals so versatile that they are chosen for carrying out vital functions by nature and by billion-dollar companies alike.

Many of a material’s properties depend on the way its molecules are arranged. Since the late 1930s, physicists use a mathematical model to describe the molecular order of liquid crystals. The so-called order parameter assigns a number that indicates how well ordered the molecules are. This model uses a positive range to describe the liquid crystals that we are used to. It can also assign a negative range that describes an “anti-ordered” state, where the molecules would avoid a certain direction rather than align along it.

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cenchempics: No strings attached Although man…

cenchempics:

No strings attached

Although many lab-scale experiments
happen inside a flask, glassware can interfere with some reactions going
on inside them. That’s why Qianqian Shi, a research fellow at Monash
University working with Monash professor Wenlong Cheng and Duyang Zang
of Northwestern Polytechnical University, performed this self-assembly
reaction in midair. First, Shi levitates a drop of water using
ultrasound waves coming out of the emitter above the drop. Then she adds
a suspension containing gold nanocubes on the surface of the water
droplet. Because there’s no glassware holding the droplet, the nanocubes
quickly spread across its entire outer surface, creating a skin. After
about 30–60 min, the water evaporates and the skin of nanocubes
collapses, leaving behind a flat bilayer (micrograph shown) of the gold
nanocubes floating in the ultrasound wave. Nanoassemblies like these
bilayers may have applications in anticounterfeiting and ultrathin
lenses.

Credit: Qianqian Shi

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Chemistry in Pictures: Midair crystallization

Lab Levitation

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