Nav: Home

Capillary shrinkage triggers high-density porous structure

February 13, 2020

Materials with both a high density and a large surface area are required in many applications, typically for energy storage under a limited space. However, they are hard to obtain by using conventional strategies. In the previous study, Quan-Hong Yang et al. reported that graphene oxide (GO) can be used to produce a porous carbon material with a high density of 1.58 g cm-3 from hydrogel by evaporation-induced drying. However, the shrinkage of hydrogels is not yet clearly illustrated and there is still no full understanding of how the capillary forces work.

Recently, the same group from Tianjin University, China explored the capillary shrinkage of graphene oxide hydrogels in Science China Materials (DOI: 10.1007/s40843-019-1227-7) based on the different surface tension of the trapped solvent.

They chose water and 1,4-dioxane which have a sole difference in surface tension to investigate the mechanism of such a network shrinkage in r-GO hydrogel, and found the surface tension of the evaporating solvent and the associated capillary force regulated by the interfacial interaction between the r-GO sheets and the solvent determined the capillary forces in the nanochannels. Solvents with higher surface tensions generate stronger capillary forces during evaporation, which can compact the r-GO framework into a dense yet porous material. More promisingly, by using solvents with different surface tensions, the microstructure of the resulting materials can be precisely manipulated and densified, realizing an excellent balance of the density and porosity in materials not limited to carbon materials. This work provides a reliable methodology of controlled shrinkage of flexible graphene network and has great potential for high volumetric performance in practical devices.
See the article: Changsheng Qi, Chong Luo, Ying Tao, Wei Lv, Chen Zhang, Yaqian Deng, Huan Li, Junwei Han, Guowei Ling and Quan-Hong Yang, "Capillary shrinkage of graphene oxide hydrogels", Science China Materials. doi: 10.1007/s40843-019-1227-7

Science China Press

Related Graphene Articles:

Graphene Flagship publishes handbook of graphene manufacturing
The EU-funded research project Graphene Flagship has published a comprehensive guide explaining how to produce and process graphene and related materials (GRMs).
How to induce magnetism in graphene
Graphene, a two-dimensional structure made of carbon, is a material with excellent mechani-cal, electronic and optical properties.
Graphene: The more you bend it, the softer it gets
New research by engineers at the University of Illinois combines atomic-scale experimentation with computer modeling to determine how much energy it takes to bend multilayer graphene -- a question that has eluded scientists since graphene was first isolated.
How do you know it's perfect graphene?
Scientists at the US Department of Energy's Ames Laboratory have discovered an indicator that reliably demonstrates a sample's high quality, and it was one that was hiding in plain sight for decades.
Graphene is 3D as well as 2D
Graphene is actually a 3D material as well as a 2D material, according to a new study from Queen Mary University of London.
How to purify water with graphene
Scientists from the National University of Science and Technology 'MISIS' together with their colleagues from Derzhavin Tambov State University and Saratov Chernyshevsky State University have figured out that graphene is capable of purifying water, making it drinkable, without further chlorination.
Decoupled graphene thanks to potassium bromide
The use of potassium bromide in the production of graphene on a copper surface can lead to better results.
1 + 1 does not equal 2 for graphene-like 2D materials
Physicists from the University of Sheffield have discovered that when two atomically thin graphene-like materials are placed on top of each other their properties change, and a material with novel hybrid properties emerges, paving the way for design of new materials and nano-devices.
Graphene's magic is in the defects
A team of researchers at the New York University Tandon School of Engineering and NYU Center for Neural Science has solved a longstanding puzzle of how to build ultra-sensitive, ultra-small electrochemical sensors with homogenous and predictable properties by discovering how to engineer graphene structure on an atomic level.
Graphene on the way to superconductivity
Scientists at HZB have found evidence that double layers of graphene have a property that may let them conduct current completely without resistance.
More Graphene News and Graphene 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

There's so much we've yet to explore–from outer space to the deep ocean to our own brains. This hour, Manoush goes on a journey through those uncharted places, led by TED Science Curator David Biello.
Now Playing: Science for the People

#555 Coronavirus
It's everywhere, and it felt disingenuous for us here at Science for the People to avoid it, so here is our episode on Coronavirus. It's ok to give this one a skip if this isn't what you want to listen to right now. Check out the links below for other great podcasts mentioned in the intro. Host Rachelle Saunders gets us up to date on what the Coronavirus is, how it spreads, and what we know and don't know with Dr Jason Kindrachuk, Assistant Professor in the Department of Medical Microbiology and infectious diseases at the University of Manitoba. And...
Now Playing: Radiolab

Dispatch 1: Numbers
In a recent Radiolab group huddle, with coronavirus unraveling around us, the team found themselves grappling with all the numbers connected to COVID-19. Our new found 6 foot bubbles of personal space. Three percent mortality rate (or 1, or 2, or 4). 7,000 cases (now, much much more). So in the wake of that meeting, we reflect on the onslaught of numbers - what they reveal, and what they hide.  Support Radiolab today at