Subscribe to our free daily newsletters
. 24/7 Space News .




Subscribe to our free daily newsletters



TECH SPACE
Semiliquid chains pulled out of a sea of microparticles
by Staff Writers
Warsaw, Poland (SPX) Jul 21, 2017


This is a chain of microparticles pulled out of the liquid by an electrode. (Source: IPC PAS)

An electrode brought to the surface of a liquid that contains microparticles can be used to pull out surprisingly long chains of particles. Curiously enough, the particles in the chains are held together by a thin layer of liquid that covers them. This spectacular phenomenon, discovered with the involvement of Polish scientists and described in the prestigious journal Nature Communications, holds promise for a broad variety of applications.

An electrode slowly rises from the surface of a liquid, pulling out individual spherical particles that, just a moment before, were chaotically dispersed in a colloidal solution. A long, regular chain of microparticles thus forms above the surface of the liquid, in a previously unnoticed phenomenon. It was first observed, studied, and described by scientists from the Institute of Physical Chemistry at the Polish Academy of Sciences (IPC PAS), the Faculty of Physics of the Adam Mickiewicz University (UAM), the Northwestern University in Evanston (Illinois, USA), and the Faculty of Physics at the University of Warsaw.

"We've all probably seen our mothers or grandmothers wear necklaces made of beads strung on a thread. The chains of microparticles fabricated and studied by our team look very similar, but they are much smaller in size. However, the most interesting thing is the physics behind this process.

The formation of these regular structures is determined by a set of phenomena that are by no means trivial, and the role of the thread that holds together the individual beads is played by... a liquid. What is more, in a necklace, the thread goes through the beads, while our thread, in this case the liquid, actually covers the microparticles," says Dr. Filip Dutka from the Faculty of Physics at the University of Warsaw.

"This phenomenon was discovered accidentally, during experiments conducted in the Institute of Physical Chemistry of the PAS," relays Dr. Zbigniew Rozynek, the lead author of the publication in the journal Nature Communications, currently employed at the Faculty of Physics at the Adam Mickiewicz University.

"I used an electrode at several hundred volts to examine glass microspheres floating on the surface of oil. When I pulled out the electrode, I was surprised to see a long and very regular chain at its tip. When I examined it under the microscope, it turned out to have the thickness of a single particle."

The phenomenon visually resembles one of the most important modern-day technological processes - namely, Prof. Jan Czochralski's method of growing monocrystals - which involves slowly pulling a rod-mounted seed crystal out of molten material.

Moreover, this method, which enables the fabrication of high-quality semiconductors for use in the electronics industry, was reportedly also discovered by accident. When writing notes, Prof. Czochralski absentmindedly dipped his pen in a crucible with cooling molten tin instead of dipping it in the inkpot. When attempting to pull out the pen, he noticed a tin filament at its tip that, on closer inspection, proved to be a monocrystal.

"The materials that are fabricated using Czochralski's method are crystals, so their structure is regular in all three dimensions. We create our structures using not atoms or molecules but microparticles arranged regularly along only one dimension. With a bit of leeway, we might therefore treat our chains as one-dimensional crystals," Dr. Rozynek says.

How can we form such a colloidal chain? We take a container with non-conductive liquid, add spherical and conductive particles, and mix them together. When we bring an electrode (for example, in the shape of a needle) to the surface of the suspension, one of the particles attaches to its tip and becomes an extension of the electrode, which happens because the particles conduct electricity.

If we apply an adequate electric voltage, we will be able to pull such spheres out of the liquid one after another, thus forming a chain of particles covered with a thin layer of the liquid. Each pair of adjacent particles is held together by a liquid capillary bridge, forming stable electric contacts.

Consequently, an electric current flows through the whole of the chain almost as efficiently as through a single particle, allowing the last particle to attract another particle from the solution.

"Hourglass-shaped capillary bridges can be found between each pair of adjacent spheres in the chain. Once the electric field is turned off, they play a crucial role: by holding the particles together, they keep the chain intact. Since the capillary bridges are simply composed of liquid, the chain is highly flexible," Dr. Dutka explains.

The chains of microparticles are formed as a result of complicated interactions of an electrical, gravitational, and capillary nature (related to the surface tension of the liquid). Here, gravity plays the role of a spoiler: if a chain gets too heavy, gravity will cut it like scissors. There is much to indicate that such chains could also be formed under zero gravity and could be then of practically any length.

"Once they form, the structures created from microparticles behave like chains: they are flexible, meaning they can be bent into various shapes. However, much depends on the type of liquid used. In some experiments, we pulled chains out of molten paraffin wax. Shortly after being pulled, the bridges would solidify and the structure would become rigid. There's also an intermediate option: if we blend, for example, resin and alcohol, the resin hardens as the alcohol evaporates. The chain is then a lot less flexible but not completely rigid," Dr. Rozynek observes.

The length of the colloidal chains depends on the number and weight of the microparticles, which is usually closely related to their size. The Polish scientists, supported by funding from the National Science Centre and the Foundation for Polish Science, conducted experiments for particles with diameters ranging from around 100 nanometers to 200 micrometers. Chains formed from micron-sized particles had up to several thousand elements and were up to several inches long.

Although the discovery was made very recently, it appears that the attractive properties of colloidal and granular chains will quickly find practical applications. Work is ongoing to apply the phenomenon to the production of thin conductive structures on substrates that vary in roughness and properties. Such structures could be used as elements in flexible circuits, among other applications. Potentially, such chains could also be formed from living cells, which opens the door to possible applications in biotechnology or even medicine.

Physics and Astronomy first appeared at the University of Warsaw in 1816, under the then Faculty of Philosophy. In 1825 the Astronomical Observatory was established. Currently, the Faculty of Physics' Institutes include Experimental Physics, Theoretical Physics, Geophysics, Department of Mathematical Methods and an Astronomical Observatory. Research covers almost all areas of modern physics, on scales from the quantum to the cosmological. The Faculty's research and teaching staff includes ca. 200 university teachers, of which 88 are employees with the title of professor. The Faculty of Physics, University of Warsaw, is attended by ca. 1000 students and more than 170 doctoral students.

Research Report: "Formation of printable granular and colloidal chains through capillary effects and dielectrophoresis"

TECH SPACE
Nature-inspired material uses liquid reinforcement
Houston TX (SPX) Jul 14, 2017
Materials scientists at Rice University are looking to nature - at the discs in human spines and the skin in ocean-diving fish, for example - for clues about designing materials with seemingly contradictory properties - flexibility and stiffness. In research appearing online in the journal Advanced Materials Interfaces, graduate student Peter Owuor, research scientist Chandra Sekhar Tiwary ... read more

Related Links
Faculty of Physics University of Warsaw
Space Technology News - Applications and Research

Thanks for being here;
We need your help. The SpaceDaily news network continues to grow but revenues have never been harder to maintain.

With the rise of Ad Blockers, and Facebook - our traditional revenue sources via quality network advertising continues to decline. And unlike so many other news sites, we don't have a paywall - with those annoying usernames and passwords.

Our news coverage takes time and effort to publish 365 days a year.

If you find our news sites informative and useful then please consider becoming a regular supporter or for now make a one off contribution.

SpaceDaily Contributor
$5 Billed Once


credit card or paypal
SpaceDaily Monthly Supporter
$5 Billed Monthly


paypal only

Comment using your Disqus, Facebook, Google or Twitter login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle

TECH SPACE
In Gulf of Mexico, NASA Evaluates How Crew Will Exit Orion

Space Tourist From Asian Country to Travel to ISS in 2019

NASA Awards Mission Systems Operations Contract

ULA to launch Dream Chaser for cargo runs to ISS for Sierra Nevada

TECH SPACE
ISRO Develops Ship-Based Antenna System to Track Satellite Launches

Aerojet Rocketdyne tests Advanced Electric Propulsion System

After two delays, SpaceX launches broadband satellite for IntelSat

Spiky ferrofluid thrusters can move satellites

TECH SPACE
Panorama Above 'Perseverance Valley'

Sol 1756: Closing time

Hubble sees Martian moon orbiting the Red Planet

Curiosity Mars Rover Begins Study of Ridge Destination

TECH SPACE
China develops sea launches to boost space commerce

Chinese satellite Zhongxing-9A enters preset orbit

Chinese Space Program: From Setback, to Manned Flights, to the Moon

Chinese Rocket Fizzles Out, Puts Other Launches on Hold

TECH SPACE
LISA Pathfinder: bake, rattle and roll

ASTROSCALE Raises a Total of $25 Million in Series C Led by Private Companies

Korean Aerospace offices raided in anti-corruption probe

Iridium Poised to Make Global Maritime Distress and Safety System History

TECH SPACE
Nature-inspired material uses liquid reinforcement

Japanese engineers develop headset-less VR system

Spacepath Communications Announces Innovative Frequency Converter Systems

Signature analysis of single molecules using their noise signals

TECH SPACE
Eyes Wide Open for MASCARA Exoplanet Hunter

Ancient worm burrows offer insights into early 'ecosystem engineers'

Molecular Outflow Launched Beyond Disk Around Young Star

A New Search for Extrasolar Planets from the Arecibo Observatory

TECH SPACE
NASA's New Horizons Team Strikes Gold in Argentina

Juno spots Jupiter's Great Red Spot

New Horizons Video Soars over Pluto's Majestic Mountains and Icy Plains

New evidence in support of the Planet Nine hypothesis




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News








The content herein, unless otherwise known to be public domain, are Copyright 1995-2017 - Space Media Network. All websites are published in Australia and are solely subject to Australian law and governed by Fair Use principals for news reporting and research purposes. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA news reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. All articles labeled "by Staff Writers" include reports supplied to Space Media Network by industry news wires, PR agencies, corporate press officers and the like. Such articles are individually curated and edited by Space Media Network staff on the basis of the report's information value to our industry and professional readership. Advertising does not imply endorsement, agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement