Nav: Home

Vapor drives a liquid-solid transition in a molecular system

March 27, 2019

The transition between a solid and a liquid phase, a key process in daily life and materials science, is generally driven by a change in temperature or pressure. However, a reversible change of state caused by other stimuli is also possible: for example, light has been used to induce solid-liquid transitions.

Tomoki Ogoshi from Kanazawa University in Japan and colleagues studied pillar[n]arene molecules -- pillar-shaped molecules that were first reported by their research group -- to which functional groups can be added to modify their physical properties. Introducing 12 n-hexyl (C6H13) chains into the molecules transform the system into a room-temperature structural liquid, that is, a system with a certain degree of order at the nanoscale but without a periodic structure (Figure 1). The liquid solidifies when exposed to a guest vapor, whose molecules replace the n-hexyl substituents in the cavities of the pillar-shaped molecules. At the same time, the substituents located outside the cavities crystallize. The result is that, on a timescale of a few seconds, the system solidifies and the transparent liquid changes to a turbid solid.

As the competitive guest vapor the authors used cyclohexane, because it fits into the cavities of the pillar-shaped molecules and is easy to remove by heating the sample under reduced pressure, a process that results in the molecular system going back to the liquid state. The adsorption and desorption processes are characterized by nuclear magnetic resonance measurements, whereas the structure of the system is studied by X-ray diffraction.

The authors also investigated the uptake of other organic vapors by the structural liquid, observing that exposure to molecules that could be absorbed in the pores of the pillar-shaped molecules always resulted in a transition to a solid phase, whereas the phase transition was not observed for exposure to gases that had a low uptake by the structural liquid.

This system can be used as a detector of alkane vapors, an unusual device. "Because of the vapor selectivity, we postulate the vapor-induced state change can be applied for new vapor detection systems," comment the authors. "Another application is adhesion materials using the guest vapor-induced state change."
-end-


Kanazawa University

Related Molecules Articles:

Water molecules dance in three
An international team of scientists has been able to shed new light on the properties of water at the molecular level.
How molecules self-assemble into superstructures
Most technical functional units are built bit by bit according to a well-designed construction plan.
Breaking down stubborn molecules
Seawater is more than just saltwater. The ocean is a veritable soup of chemicals.
Shaping the rings of molecules
Canadian chemists discover a natural process to control the shape of 'macrocycles,' molecules of large rings of atoms, for use in pharmaceuticals and electronics.
The mysterious movement of water molecules
Water is all around us and essential for life. Nevertheless, research into its behaviour at the atomic level -- above all how it interacts with surfaces -- is thin on the ground.
Spectroscopy: A fine sense for molecules
Scientists at the Laboratory for Attosecond Physics have developed a unique laser technology for the analysis of the molecular composition of biological samples.
Looking at the good vibes of molecules
Label-free dynamic detection of biomolecules is a major challenge in live-cell microscopy.
Colliding molecules and antiparticles
A study by Marcos Barp and Felipe Arretche from Brazil published in EPJ D shows a model of the interaction between positrons and simple molecules that is in good agreement with experimental results.
Discovery of periodic tables for molecules
Scientists at Tokyo Institute of Technology (Tokyo Tech) develop tables similar to the periodic table of elements but for molecules.
New method for imaging biological molecules
Researchers at Karolinska Institutet in Sweden have, together with colleagues from Aalto University in Finland, developed a new method for creating images of molecules in cells or tissue samples.
More Molecules News and Molecules Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Listen Again: Meditations on Loneliness
Original broadcast date: April 24, 2020. We're a social species now living in isolation. But loneliness was a problem well before this era of social distancing. This hour, TED speakers explore how we can live and make peace with loneliness. Guests on the show include author and illustrator Jonny Sun, psychologist Susan Pinker, architect Grace Kim, and writer Suleika Jaouad.
Now Playing: Science for the People

#565 The Great Wide Indoors
We're all spending a bit more time indoors this summer than we probably figured. But did you ever stop to think about why the places we live and work as designed the way they are? And how they could be designed better? We're talking with Emily Anthes about her new book "The Great Indoors: The Surprising Science of how Buildings Shape our Behavior, Health and Happiness".
Now Playing: Radiolab

The Third. A TED Talk.
Jad gives a TED talk about his life as a journalist and how Radiolab has evolved over the years. Here's how TED described it:How do you end a story? Host of Radiolab Jad Abumrad tells how his search for an answer led him home to the mountains of Tennessee, where he met an unexpected teacher: Dolly Parton.Jad Nicholas Abumrad is a Lebanese-American radio host, composer and producer. He is the founder of the syndicated public radio program Radiolab, which is broadcast on over 600 radio stations nationwide and is downloaded more than 120 million times a year as a podcast. He also created More Perfect, a podcast that tells the stories behind the Supreme Court's most famous decisions. And most recently, Dolly Parton's America, a nine-episode podcast exploring the life and times of the iconic country music star. Abumrad has received three Peabody Awards and was named a MacArthur Fellow in 2011.