Featured Research

from universities, journals, and other organizations

Patterns of particles generated by surface charges: How disorder turns into order

Date:
February 4, 2014
Source:
Vienna University of Technology, TU Vienna
Summary:
Tuning the material structure at the nanoscale level can be really hard to achieve -- but what if we had small particles, which assemble all by themselves, creating the required structure? The phenomenon of self-assembly is being investigated by studying inhomogeneously charged particles. Depending on different parameters, they can form gel-like or crystal-like structures. This kind of self-assembly holds great promise for nanotechnology.

Disordered gel-like structures with interconnected rings.
Credit: Image courtesy of Vienna University of Technology, TU Vienna

Disorder turns into order: Scientists at the Vienna University of Technology can show how intricate structures can emerge from inhomogeneously charged particles.

Tuning the material structure at the nanoscale level can be really hard to achieve -- but what if we had small particles, which assemble all by themselves, creating the required structure? At the Vienna University of Technology (TU Wien), the phenomenon of self-assembly is being investigated by studying inhomogeneously charged particles. Depending on different parameters, they can form gel-like or crystal-like structures. This kind of self-assembly holds great promise for nanotechnology.

Micro Particles with Specially Structured Surfaces

Emanuela Bianchi is a scientist in Prof. Gerhard Kahls research group at the Institute for Theoretical Physics of the Vienna University of Technology. In her computer simulations, she reproduces the bahavior of particles which are no bigger than a few micrometers -- comparable to viruses or small bacteria. She is especially interested in nanoparticles with a complicated surface, consisting of different kinds of patches distinguished by different physical properties.

Recent work (funded via an Elise Richter Fellowhip by the FWF) has focused on particles with inhomogeneously charged surface regions: The majority of the particle carries negative electric charge, but the polar regions on the top and at the bottom of the particle are positively charged. "Due to the fact that like charges repel while opposite charges attract each other," says Emanuela Bianchi, "our particles tend to align in such a way that the pole of one particle points towards the equator of the other." But when many of these particles interact, things get more complicated.

Computer simulations have now been able to show how these particles behave when they are trapped between two planes so that they have to align in quasi two dimensional structures. The results showed that there are different possible configurations: Sometimes the particles are tightly packed in a simple hexagonal structure, which is well known from crystals. Sometimes, less ordered gel-like structures emerge, with interconnected rings of five or six particles.

"With our model, we can find out which parameters determine the emerging structure," says Emanuela Bianchi. The size of the positively charged polar patches plays an especially important role. Spheres on which the border between negative and positive charge is at 45 degrees latitude create much more ordered structures than particles on which this border is closer at the pole, at 60 degrees. The result can also be influenced by tuning the electrical charge of the floor plate on which the particles rest -- a parameter which is very easy to control in an experiment. Such a parameter controls the size of the aggregates and can even be responsible for a complete suppression of the particle aggregation.

Materials with Taylor Made Properties

Understanding the self-assembly of microparticles opens the door to designing particles which automatically form taylor-made structures. Depending on the microscopic alignment of the particles, they create surface types with different densities and different responses to external stimuli (e.g. elcetromagnetic fields). This means that self-assembled structures could for instance be used to create filters with tunable porosity. "Especially for biomedical applications, this could have many possible applications," says Emanuela Bianchi. The results of the research project have been published in the journal "ACS Nano."


Story Source:

The above story is based on materials provided by Vienna University of Technology, TU Vienna. Note: Materials may be edited for content and length.


Journal Reference:

  1. Emanuela Bianchi, Christos N. Likos, Gerhard Kahl. Self-Assembly of Heterogeneously Charged Particles under Confinement. ACS Nano, 2013; 7 (5): 4657 DOI: 10.1021/nn401487m

Cite This Page:

Vienna University of Technology, TU Vienna. "Patterns of particles generated by surface charges: How disorder turns into order." ScienceDaily. ScienceDaily, 4 February 2014. <www.sciencedaily.com/releases/2014/02/140204073825.htm>.
Vienna University of Technology, TU Vienna. (2014, February 4). Patterns of particles generated by surface charges: How disorder turns into order. ScienceDaily. Retrieved October 22, 2014 from www.sciencedaily.com/releases/2014/02/140204073825.htm
Vienna University of Technology, TU Vienna. "Patterns of particles generated by surface charges: How disorder turns into order." ScienceDaily. www.sciencedaily.com/releases/2014/02/140204073825.htm (accessed October 22, 2014).

Share This



More Matter & Energy News

Wednesday, October 22, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Chameleon Camouflage to Give Tanks Cloaking Capabilities

Chameleon Camouflage to Give Tanks Cloaking Capabilities

Reuters - Innovations Video Online (Oct. 22, 2014) — Inspired by the way a chameleon changes its colour to disguise itself; scientists in Poland want to replace traditional camouflage paint with thousands of electrochromic plates that will continuously change colour to blend with its surroundings. The first PL-01 concept tank prototype will be tested within a few years, with scientists predicting that a similar technology could even be woven into the fabric of a soldiers' clothing making them virtually invisible to the naked eye. Matthew Stock reports. Video provided by Reuters
Powered by NewsLook.com
Jet Sales Lift Boeing Profit 18 Pct.

Jet Sales Lift Boeing Profit 18 Pct.

Reuters - Business Video Online (Oct. 22, 2014) — Strong jet demand has pushed Boeing to raise its profit forecast for the third time, but analysts were disappointed by its small cash flow. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Internet of Things Aims to Smarten Your Life

Internet of Things Aims to Smarten Your Life

AP (Oct. 22, 2014) — As more and more Bluetooth-enabled devices are reaching consumers, developers are busy connecting them together as part of the Internet of Things. (Oct. 22) Video provided by AP
Powered by NewsLook.com
What Is Magic Leap, And Why Is It Worth $500M?

What Is Magic Leap, And Why Is It Worth $500M?

Newsy (Oct. 22, 2014) — Magic Leap isn't publicizing much more than a description of its product, but it’s been enough for Google and others to invest more than $500M. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:

Strange & Offbeat Stories

 

Space & Time

Matter & Energy

Computers & Math

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins