Wisconsin – A group of researchers from the University of Wisconsin have discovered that topological defects in liquid crystals can selectively trigger processes of molecular self-assembly for nanomaterials.

The study was published in the journal Nature Materials and it focused on studying the use of topological defects in these liquid crystals, which are already widely applied to organize colloidal dispersion. But now, they are also used as miniscule tubes to form new materials and nanoscale structures. The discovery could have applications in fields as diverse as electronics and medicine.

“By controlling the geometry of the system, we can send these channels from any one point to any other point. It’s quite a versatile approach.” said Nicholas Abbott, a UW–Madison professor of chemical and biological engineering, in a report by News Wise.

The liquid crystal state is a distinct phase of matter observed between the crystalline (solid) and isotopic (liquid) states. (Credit: Simon Fraser University)

Abbott, who studies interfacial and colloidal phenomena in a range of soft material systems, has been working with liquid crystals for about 20 years. The team led by Abbott has been successful in creating defects similar to small ropes, termed as “disclinations” and has filled them with amphiphilic (water- and fat-loving) molecules.

After that, they can link together assemblies of molecules and remove the liquid crystal templates, leaving behind the water-loving particles like building blocks in a stronger nanoscale structure.

“We’ve done a lot of work in the past at the interfaces of liquid crystals, but we’re now looking inside the liquid crystal. We’re looking at how to use the internal structure of liquid crystals to direct the organization of molecules. There’s no prior example of using a defect in a liquid crystal to template molecular organization” said Abbott to News Wise.

The researchers included UW-Madison graduate students Xiaoguang Wang, Daniel S. Miller and Emre Bukusoglu, and Juan J. de Pablo, a former UW–Madison engineering professor.


So far, possibilities reach the future assembling of inorganic materials, such as metallic wires and various semiconducting structures, as well. There’s also potential for mimicking selective transport through a membrane, designing a defect so that one type of molecule can move along it, and another can’t.

“This is an enabling discovery” Abbott said to Phys.org, “We’re not looking for a specific application, but we’re showing a versatile method of fabrication that can lead to structures you can’t make any other way.”

Source: Nature Materials