Nav: Home

Nano-infused ceramic could report on its own health

February 05, 2019

HOUSTON - (Feb. 5, 2019) - A ceramic that becomes more electrically conductive under elastic strain and less conductive under plastic strain could lead to a new generation of sensors embedded into structures like buildings, bridges and aircraft able to monitor their own health.

The electrical disparity fostered by the two types of strain was not obvious until Rice University's Rouzbeh Shahsavari, an assistant professor of civil and environmental engineering and of materials science and nanoengineering, and his colleagues modeled a novel two-dimensional compound, graphene-boron-nitride (GBN).

Under elastic strain, the internal structure of a material stretched like a rubber band does not change. But the same material under plastic strain -- caused in this case by stretching it far enough beyond elasticity to deform -- distorts its crystalline lattice. GBN, it turns out, shows different electrical properties in each case, making it a worthy candidate as a structural sensor.

Shahsavari had already determined that hexagonal-boron nitride - aka white graphene - can improve the properties of ceramics. He and his colleagues have now discovered that adding graphene makes them even stronger and more versatile, along with their surprising electrical properties.

The magic lies in the ability of two-dimensional, carbon-based graphene and white graphene to bond with each other in a variety of ways, depending on their relative concentrations. Though graphene and white graphene naturally avoid water, causing them to clump, the combined nanosheets easily disperse in a slurry during the ceramic's manufacture.

The resulting ceramics, according to the authors' theoretical models, would become tunable semiconductors with enhanced elasticity, strength and ductility.

The research led by Shahsavari and Asghar Habibnejad Korayem, an assistant professor of structural engineering at Iran University of Science and Technology and a research fellow at Monash University in Melbourne, Australia, appears in the American Chemical Society journal Applied Materials and Interfaces.

Graphene is a well-studied form of carbon known for its lack of a band gap - the region an electron has to leap to make a material conductive. With no band gap, graphene is a metallic conductor. White graphene, with its wide band gap, is an insulator. So the greater the ratio of graphene in the 2D compound, the more conductive the material will be.

Mixed into the ceramic in a high enough concentration, the 2D compound dubbed GBN would form a network as conductive as the amount of carbon in the matrix allows. That gives the overall composite a tunable band gap that could lend itself to a variety of electrical applications.

"Fusing 2D materials like graphene and boron nitride in ceramics and cements enables new compositions and properties we can't achieve with either graphene or boron nitride by themselves," Shahsavari said.

The team used density functional theory calculations to model variations of the 2D compound mixed with tobermorite, a calcium silicate hydrate material commonly used as cement for concrete. They determined the oxygen-boron bonds formed in the ceramic would turn it into a p-type semiconductor.

Tobermorite by itself has a large band gap of about 4.5 electron volts, but the researchers calculated that when mixed with GBN nanosheets of equal parts graphene and white graphene, that gap would shrink to 0.624 electron volts.

When strained in the elastic regime, the ceramic's band gap dropped, making the material more conductive, but when stretched beyond elasticity - that is, in the plastic regime -- it became less conductive. That switch, the researchers said, makes it a promising material for self-sensing and structural health monitoring applications.

The researchers suggested other 2D sheets with molybdenum disulfide, niobium diselenide or layered double hydroxides may provide similar opportunities for the bottom-up design of tunable, multifunctional composites. "This would provide a fundamental platform for cement and concrete reinforcement at their smallest possible dimension," Shahsavari said.
-end-
Co-authors of the paper are graduate students Ehsan Hosseini and Mohammad Zakertabrizi of the Iran University of Science and Technology. The National Science Foundation and the Australian Research Council supported the research.

David Ruth, 713-348-6327, david@rice.edu
Mike Williams, 713-348-6728, mikewilliams@rice.edu

Read the abstract at https://pubs.acs.org/doi/10.1021/acsami.8b19409

This news release can be found online at https://news.rice.edu/2019/02/05/nano-infused-ceramic-could-report-on-its-own-health/

Follow Rice News and Media Relations via Twitter @RiceUNews.

Related materials:

White graphene makes ceramics multifunctional: http://news.rice.edu/2018/01/11/white-graphene-makes-ceramics-multifunctional-2/

Multiscale Materials Laboratory (Shahsavari Lab): http://rouzbeh.rice.edu/

Asghar Habibnejad Korayem: http://www.iust.ac.ir/content/40345/Dr.-Habibnejad-Korayem,-Asghar

George R. Brown School of Engineering: http://engineering.rice.edu

Rice Department of Civil and Environmental Engineering: http://www.ceve.rice.edu

Rice Department of Materials Science and NanoEngineering: https://msne.rice.edu

Image for download:

https://news-network.rice.edu/news/files/2019/01/0128_CERAMIC-1-WEB-2khpzam.jpg

Ceramics with networked nanosheets of graphene and white graphene would have the unique ability to alter their electrical properties when strained, according to a researcher at Rice University. The surprising ability could lead to new types of structural sensors. (Credit: Rouzbeh Shahsavari/Rice University)

Located on a 300-acre forested campus in Houston, Rice University is consistently ranked among the nation's top 20 universities by U.S. News & World Report. Rice has highly respected schools of Architecture, Business, Continuing Studies, Engineering, Humanities, Music, Natural Sciences and Social Sciences and is home to the Baker Institute for Public Policy. With 3,962 undergraduates and 3,027 graduate students, Rice's undergraduate student-to-faculty ratio is just under 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice is ranked No. 1 for lots of race/class interaction and No. 2 for quality of life by the Princeton Review. Rice is also rated as a best value among private universities by Kiplinger's Personal Finance. To read "What they're saying about Rice," go to http://tinyurl.com/RiceUniversityoverview.

Rice University

Related Graphene Articles:

New chemical method could revolutionize graphene
University of Illinois at Chicago scientists have discovered a new chemical method that enables graphene to be incorporated into a wide range of applications while maintaining its ultra-fast electronics.
Searching beyond graphene for new wonder materials
Graphene, the two-dimensional, ultra lightweight and super-strong carbon film, has been hailed as a wonder material since its discovery in 2004.
New method of characterizing graphene
Scientists have developed a new method of characterizing graphene's properties without applying disruptive electrical contacts, allowing them to investigate both the resistance and quantum capacitance of graphene and other two-dimensional materials.
Chemically tailored graphene
Graphene is considered as one of the most promising new materials.
Beyond graphene: Advances make reduced graphene oxide electronics feasible
Researchers have developed a technique for converting positively charged (p-type) reduced graphene oxide (rGO) into negatively charged (n-type) rGO, creating a layered material that can be used to develop rGO-based transistors for use in electronic devices.
The Graphene 2017 Conference connects Barcelona with the international graphene-based industry
This prestigious Conference to be held at the Barcelona International Convention Centre (March 28-31) aims to bring together academia and industry to integrate new graphene technologies into practical applications.
Graphene from soybeans
A breakthrough by CSIRO-led scientists has made the world's strongest material more commercially viable, thanks to the humble soybean.
First use of graphene to detect cancer cells
By interfacing brain cells onto graphene, researchers at the University of Illinois at Chicago have shown they can differentiate a single hyperactive cancerous cell from a normal cell, pointing the way to developing a simple, noninvasive tool for early cancer diagnosis.
Development of graphene microwave photodetector
DGIST developed cryogenic microwave photodetector which is able to detect 100,000 times smaller light energy compared to the existing photedetectors.
Adding hydrogen to graphene
IBS researchers report a fundamental study of how graphene is hydrogenated.

Related Graphene Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Anthropomorphic
Do animals grieve? Do they have language or consciousness? For a long time, scientists resisted the urge to look for human qualities in animals. This hour, TED speakers explore how that is changing. Guests include biological anthropologist Barbara King, dolphin researcher Denise Herzing, primatologist Frans de Waal, and ecologist Carl Safina.
Now Playing: Science for the People

#SB2 2019 Science Birthday Minisode: Mary Golda Ross
Our second annual Science Birthday is here, and this year we celebrate the wonderful Mary Golda Ross, born 9 August 1908. She died in 2008 at age 99, but left a lasting mark on the science of rocketry and space exploration as an early woman in engineering, and one of the first Native Americans in engineering. Join Rachelle and Bethany for this very special birthday minisode celebrating Mary and her achievements. Thanks to our Patreons who make this show possible! Read more about Mary G. Ross: Interview with Mary Ross on Lash Publications International, by Laurel Sheppard Meet Mary Golda...