Scrutinising the tip of molecular probes

February 29, 2016
The solid lines indicate the temperature range used to estimate the amount of molecules loaded onto the probe.

Studies of molecules confined to nano- or micropores are of considerable interest to physicists. That's because they can manipulate or stabilise molecules in unstable states or obtain new materials with special properties. In a new study published in EPJ Plus , Stefan Frunza from the National Institute of Materials Physics in Romania and colleagues have discovered the properties of the surface layer in probe molecules on the surface of oxide particles. These properties depend on the interaction at the interface. In this particular study, probes are formed by adsorption of rod-like cyanophenyl derivates on the surface of oxide particles. The authors found that their surface layers behave like glass-forming liquids.

What physicists already knew is that confinement of molecules may induce disorder. Confinement and disorder have a considerable influence both on the structure of the trapped molecule but also on its mobility. As a result, they also affect aspects such as molecular dynamics upon relaxation of the material. Such structurally well-defined monolayers on solid surfaces will allow researchers to model a large variety of interfacial phenomena.

The authors used data from infrared spectroscopy and thermogravimetry to identify the strength of the interaction between the probe and the oxide surface, which also helped them determine the type of bonding to the surface. They established two key parameters: firstly, the density of the adsorbed surface species used to characterise the interaction of the probe molecule with the surface. This parameter depends on the nature of the nanoparticles and on the existence of nanopores. The second parameter expresses the ratio of the molecules contained in the having a glassy dynamic behaviour to the total number of the adsorbed molecules.

The study shows that the value of the surface density can be used to divide the composites into several groups. This helps to determine that the probe molecules applied to the surface of a given group can display similar interactions, as observed in surfaces of the same family.

Explore further: Nanodevice, build thyself

More information: Stefan Frunza et al. Rod-like cyanophenyl probe molecules nanoconfined to oxide particles: Density of adsorbed surface species, The European Physical Journal Plus (2016). DOI: 10.1140/epjp/i2016-16027-5

Related Stories

Nanodevice, build thyself

January 14, 2016

As we continue to shrink electronic components, top-down manufacturing methods begin to approach a physical limit at the nanoscale. Rather than continue to chip away at this limit, one solution of interest involves using ...

Platinum and iron oxide working together get the job done

September 16, 2015

Scientists at the Vienna University of Technology (TU Wien) have figured out how a platinum catalyst works. Its remarkable properties are not just due to the platinum, the iron-oxide substrate beneath also plays a role.

Pole dancing water molecules: How water learns to dance

December 21, 2015

Perovskites are materials used in batteries, fuel cells, and electronic components, and occur in nature as minerals. Despite their important role in technology, little is known about the reactivity of their surfaces. Professor ...

Graphene decharging and molecular shielding

February 8, 2016

A new joint theoretical and experimental study suggests that graphene sheets efficiently shield chemical interactions. One of the promising applications of this phenomenon is associated with improving the quality of 2D materials ...

Recommended for you

Hydrogen from sunlight—but as a dark reaction

December 9, 2016

The storage of photogenerated electric energy and its release on demand are still among the main obstacles in artificial photosynthesis. One of the most promising, recently identified photocatalytic new materials is inexpensive ...

Cloud formation—how feldspar acts as ice nucleus

December 9, 2016

In the atmosphere, feldspar particles act as ice nuclei that make ice crystals grow in clouds and enable precipitation. The discovery was made by researchers of Karlsruhe Institute of Technology (KIT) and University College ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.