Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Stuttgart researchers discover ferroelectric liquid crystal comprising mainly water

18.11.2013
About communicating molecular layers

Although certain liquid crystals mainly comprise water, a spontaneous alignment of electrical dipoles could incur in them and consequently a spontaneous electrical polarisation could occur macroscopically: chemists from the Institute of Physical Chemistry at the University of Stuttgart (IPC) were able to show this and report about it in the leading trade journal “Applied Chemistry”*).


Molecular layers
University of Stuttgart IPC

These so-called lyotropic liquid crystals are ordered solutions of organic molecules, for example in water. In the liquid crystal examined, chiral organic molecules with a specific inclination angle arrange themselves in layers. The solvent is between these layers. The surprising thing is: although the water layers between the molecular layers are comparatively thick (approx. 2 nanometres), the organic molecules have the same direction of inclination in each layer.

If an electrical field is created, it is possible to switch backwards and forwards between opposing directions of inclination through changing the field direction (see illustration). With this evidence of ferroelectricity in a liquid crystal solution was provided for the first time.

Materials showing evidence of a spontaneous electrical polarisation even without electrical field are described as ferroelectrics. Ferroelectricity was first discovered by Joseph Valasek at the beginning of the 20th century and was only known in solid crystals for a long time. Up to now it has been considered extremely improbable that ferroelectricity can also occur in lyotropic liquid crystals since these largely comprise small, disorganised solvent molecules.

This question already aroused the scientific ambition of the research group of Prof. Dr. Frank Gießelmann at the Institute of Physical Chemistry at the University of Stuttgart some years ago. After some failures and the experience gained through this, the team has now been successful in customising a new organic “hybrid molecule“ that combines a water-soluble chiral head group and a water-insoluble, stiff residue.

The new substance was examined by Johanna Bruckner in the course of her doctoral studies for which she received a scholarship from the State Graduate Sponsorship Programme. The young researcher experimented with various solvents, concentrations and temperature ranges. She ultimately found the suitable conditions under which lyotropic liquid crystal with a water proportion of up to 60 percent actually showed a spontaneous electrical polarisation and with this ferroelectrical properties. Bruckner was able to prove this with electro-optical measurements under the polarisation microscope.

The prerequisite for this effect, however, is that the direction of inclination is equal in all molecular layers. The exciting question concerning scientists is now: how do the molecular layers “know” how their neighbouring layers are aligned, although they are separated from each other through the comparatively disorganised water molecules and consequently no connection actually exists between them. How can they “communicate” with each other in spite of this?

Applications in sensor technology conceivable

Prof. Frank Gießelmann explained: “We would now like to clarify, of course, how this phenomenon is possible. It initially concerns pure fundamental research yet future applications would also be conceivable.“ Applications in the sensor technology of chiral molecules would be possible, as can often be found for example in pharmaceutical active agents. If they are dissolved in the water layers of the new liquid crystal, they induce measureable changes of its spontaneous electrical polarisation, depending on the purity and concentration of the molecules.

The history of the liquid crystals, which were discovered exactly 125 years ago, makes it clear that fundamental research which was only of academic interest for a long time, can suddenly gain in great economic importance reaching far into the spheres of life of mankind, such as the rapid spread of liquid crystal displays (LCD), for example for notebooks, televisions and mobile phones.

*) Johanna R. Bruckner, Jan H. Porada, Clarissa F. Dietrich, Ingo Dierking and
Frank Giesselmannn: "A Lyotropic Chiral Smectic C Liquid Crystal with Polar Electrooptic Switching", Applied Chemistry International Edition 2013, 52, 8934 –8937. Online-Version: DOI: 10.1002/anie.201303344
Image description:
Depending on the direction of inclination of the molecules in the layers (left resp. right top), the direction of spontaneous polarisation changes. Through creating an electrical field, switches can be made backwards and forwards between these two directions, through which the texture in the polarisation microscope changes (left resp. right bottom).
Further information:
Prof. Dr. Frank Gießelmann, Institute of Physical Chemistry at the University of Stuttgart, Tel. 0711-685-64460, Email: f.giesselmann(at)ipc.uni-stuttgart.de

Andrea Mayer-Grenu | idw
Further information:
http://www.uni-stuttgart.de

More articles from Life Sciences:

nachricht Embryonic development: How do limbs develop from cells?
18.05.2018 | Humboldt-Universität zu Berlin

nachricht Reading histone modifications, an oncoprotein is modified in return
18.05.2018 | American Society for Biochemistry and Molecular Biology

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Explanation for puzzling quantum oscillations has been found

So-called quantum many-body scars allow quantum systems to stay out of equilibrium much longer, explaining experiment | Study published in Nature Physics

Recently, researchers from Harvard and MIT succeeded in trapping a record 53 atoms and individually controlling their quantum state, realizing what is called a...

Im Focus: Dozens of binaries from Milky Way's globular clusters could be detectable by LISA

Next-generation gravitational wave detector in space will complement LIGO on Earth

The historic first detection of gravitational waves from colliding black holes far outside our galaxy opened a new window to understanding the universe. A...

Im Focus: Entangled atoms shine in unison

A team led by Austrian experimental physicist Rainer Blatt has succeeded in characterizing the quantum entanglement of two spatially separated atoms by observing their light emission. This fundamental demonstration could lead to the development of highly sensitive optical gradiometers for the precise measurement of the gravitational field or the earth's magnetic field.

The age of quantum technology has long been heralded. Decades of research into the quantum world have led to the development of methods that make it possible...

Im Focus: Computer-Designed Customized Regenerative Heart Valves

Cardiovascular tissue engineering aims to treat heart disease with prostheses that grow and regenerate. Now, researchers from the University of Zurich, the Technical University Eindhoven and the Charité Berlin have successfully implanted regenerative heart valves, designed with the aid of computer simulations, into sheep for the first time.

Producing living tissue or organs based on human cells is one of the main research fields in regenerative medicine. Tissue engineering, which involves growing...

Im Focus: Light-induced superconductivity under high pressure

A team of scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg investigated optically-induced superconductivity in the alkali-doped fulleride K3C60under high external pressures. This study allowed, on one hand, to uniquely assess the nature of the transient state as a superconducting phase. In addition, it unveiled the possibility to induce superconductivity in K3C60 at temperatures far above the -170 degrees Celsius hypothesized previously, and rather all the way to room temperature. The paper by Cantaluppi et al has been published in Nature Physics.

Unlike ordinary metals, superconductors have the unique capability of transporting electrical currents without any loss. Nowadays, their technological...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Save the date: Forum European Neuroscience – 07-11 July 2018 in Berlin, Germany

02.05.2018 | Event News

Invitation to the upcoming "Current Topics in Bioinformatics: Big Data in Genomics and Medicine"

13.04.2018 | Event News

Unique scope of UV LED technologies and applications presented in Berlin: ICULTA-2018

12.04.2018 | Event News

 
Latest News

Supersonic waves may help electronics beat the heat

18.05.2018 | Power and Electrical Engineering

Keeping a Close Eye on Ice Loss

18.05.2018 | Information Technology

CrowdWater: An App for Flood Research

18.05.2018 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>