Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Mismatched materials can be tough enough: Rice University scientists analyze molecular detail of cement-polymer bonds

Rice University researchers Rouzbeh Shahsavari, left, and Navid Sakhavand analyzed the molecular interface between cement and a polymer in a new Langmuir paper.Credit: Jeff Fitlow/Rice University
Rice University researchers Rouzbeh Shahsavari, left, and Navid Sakhavand analyzed the molecular interface between cement and a polymer in a new Langmuir paper.

Credit: Jeff Fitlow/Rice University

Abstract:
Rice University researchers have for the first time detailed the molecular mechanism that makes a particular combination of cement and polymer glue so tough.

Mismatched materials can be tough enough: Rice University scientists analyze molecular detail of cement-polymer bonds

Houston, TX | Posted on June 10th, 2013

The theoretical research by Rice materials scientist Rouzbeh Shahsavari and his group led to a fine picture of how hydrogen bonds control the properties of hybrid organic-inorganic materials. The finding has implications for understanding the interface bonding that is often a roadblock to improved composite properties.

The research is detailed in the American Chemical Society journal Langmuir.

The Rice researchers said their work has the potential to help fine-tune advanced materials well beyond the cement-polymer compound they studied. "Natural materials like bones, teeth and shells all have a hybrid of soft and stiff material inside, arranged in a brick-and-mortar pattern," Shahsavari said. "This has inspired humans to build engineered composites by mimicking those natural designs."

Building such composites requires a clear understanding of what's happening when materials that aren't necessarily compatible are combined.

"This could have applications for composites in cars, airplanes and civil engineering materials," Shahsavari said. "Here, our focus is on inorganic silicates like cement (a key strengthening component of concrete) interacting with a polymer to provide a hybrid composite with high toughness and ductility. Otherwise, cement by itself is a brittle material."

He said understanding bonds at the molecular level should help manufacturers design stronger, lighter composites from the bottom up. For example, cars that use advanced compounds could be lighter and more fuel-efficient while retaining the toughness that lets them absorb energy in a crash by crumpling instead of shattering. The same analogy is true for civil engineering composites that absorb the energy of an earthquake rather than fracture and collapse.

"Toughness by definition is the ability of the material to deform before fracture," he said.

Shahsaveri, graduate student and lead author Navid Sakhavand and former Rice postdoctoral researcher Prakash Muthuramalingam started by studying recent experiments on polymer-silicate compounds (polyvinyl alcohol mixed with cement in gel form) that suggested hydrogen bonds must be responsible for interfacial adhesion. They determined that very different geometries across the interface of the two materials complicate the process of figuring out the hydrogen-bonding pattern and how the molecules might bond and/or tear under stress.

But it wasn't impossible. The Rice researchers built molecular models that combined strands of polyvinyl alcohol and layered chains of tobermorite, a mineral they said is a natural analog of the previously studied cement gel.

At the molecular interface, they determined the hydrogen bonds most responsible for adhesion don't quite line up. Subjecting their computer models to shear forces showed them how hydrogen bonds on both sides would break and reform as the polymer was pulled across the silicate. Subsequent calculations based on the energies of individual atomic pairs let them determine the seven types of hydrogen bonds possible where the two materials meet, and precisely which type of hydrogen bonds and how many of them should line up for maximum toughness.

This might be a bit counterintuitive, Shahsaveri said, since a hydrogen bond is typically weak, but the cooperative action of several can result in significant adhesion and toughness. This can help determine the optimum overlap length and design parameters for manufacturing tough hybrid composites.

"The overall goal is to improve mechanical properties," Sakhavand said. "We started with concrete, which is the most-used composite material on Earth. Billions of dollars are spent on it every year just in the United States. Any small improvement we can make for concrete is going to significantly change the industry."

The theoretical models they've developed can be applied in many ways, Sakhavand said. "All of these can easily be extended to any synthetic material," he said, suggesting their formula can help experimentalists cut the amount of time spent on trial and error in the design of novel compounds.

The research team performed calculations on the Data Analysis and Visualization Cyber Infrastructure (DAVinCI) system funded by the National Science Foundation and operated by the Ken Kennedy Institute for Information Technology at Rice. An IBM Shared University Research Award in partnership with Cisco, QLogic and Adaptive Computing also supported the research.

####

About 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 3,708 undergraduates and 2,374 graduate students, Rice's undergraduate student-to-faculty ratio is 6-to-1. Its residential college system builds close-knit communities and lifelong friendships, just one reason why Rice has been ranked No. 1 for best quality of life multiple times by the Princeton Review and No. 2 for "best value" among private universities by Kiplinger's Personal Finance. To read "What they're saying about Rice," go to tinyurl.com/AboutRiceU.

Follow Rice News and Media Relations via Twitter @RiceUNews

For more information, please click here

Contacts:
Jeff Falk
713-348-6775


Mike Williams
713-348-6728

Copyright © Rice University

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related Links

Read the abstract at:

Multiscale Materials Modeling Lab:

Related News Press

News and information

Nano Ruffles in Brain Matter: Freiburg researchers decipher the role of nanostructures around brain cells in central nervous system function October 31st, 2014

Gold nanoparticle chains confine light to the nanoscale October 31st, 2014

'Nanomotor lithography' answers call for affordable, simpler device manufacturing October 31st, 2014

Device invented at Johns Hopkins provides up-close look at cancer on the move: Microscopic view of metastasis could give insight about how to keep cancer in check October 31st, 2014

Govt.-Legislation/Regulation/Funding/Policy

Gold nanoparticle chains confine light to the nanoscale October 31st, 2014

'Nanomotor lithography' answers call for affordable, simpler device manufacturing October 31st, 2014

Device invented at Johns Hopkins provides up-close look at cancer on the move: Microscopic view of metastasis could give insight about how to keep cancer in check October 31st, 2014

'Electronic skin' could improve early breast cancer detection October 29th, 2014

Discoveries

Nano Ruffles in Brain Matter: Freiburg researchers decipher the role of nanostructures around brain cells in central nervous system function October 31st, 2014

Gold nanoparticle chains confine light to the nanoscale October 31st, 2014

'Nanomotor lithography' answers call for affordable, simpler device manufacturing October 31st, 2014

Device invented at Johns Hopkins provides up-close look at cancer on the move: Microscopic view of metastasis could give insight about how to keep cancer in check October 31st, 2014

Materials/Metamaterials

Production of Biocompatible Polymers in Iran October 30th, 2014

New solar power material converts 90 percent of captured light into heat: SunShot Project aims to make solar cost competitive October 29th, 2014

Watching the hidden life of materials: Ultrafast electron diffraction experiments open a new window on the microscopic world October 27th, 2014

Polymeric Scaffold Recreates Bladder Tissue October 27th, 2014

Announcements

Nano Ruffles in Brain Matter: Freiburg researchers decipher the role of nanostructures around brain cells in central nervous system function October 31st, 2014

Gold nanoparticle chains confine light to the nanoscale October 31st, 2014

'Nanomotor lithography' answers call for affordable, simpler device manufacturing October 31st, 2014

Device invented at Johns Hopkins provides up-close look at cancer on the move: Microscopic view of metastasis could give insight about how to keep cancer in check October 31st, 2014

Interviews/Book Reviews/Essays/Reports/Podcasts/Journals

Nano Ruffles in Brain Matter: Freiburg researchers decipher the role of nanostructures around brain cells in central nervous system function October 31st, 2014

'Nanomotor lithography' answers call for affordable, simpler device manufacturing October 31st, 2014

Device invented at Johns Hopkins provides up-close look at cancer on the move: Microscopic view of metastasis could give insight about how to keep cancer in check October 31st, 2014

Production of Biocompatible Polymers in Iran October 30th, 2014

Grants/Awards/Scholarships/Gifts/Contests/Honors/Records

Microrockets fueled by water neutralize chemical and biological warfare agents October 29th, 2014

New nanodevice to improve cancer treatment monitoring October 27th, 2014

Special UO microscope captures defects in nanotubes: University of Oregon chemists provide a detailed view of traps that disrupt energy flow, possibly pointing toward improved charge-carrying devices October 21st, 2014

Crystallizing the DNA nanotechnology dream: Scientists have designed the first large DNA crystals with precisely prescribed depths and complex 3D features, which could create revolutionary nanodevices October 20th, 2014

Construction

7th Nanotechnology Festival, Exhibition Kicks Off Work in Iran October 7th, 2014

Iranian Scientists Obtain Nanostructured Steel Production Method September 25th, 2014

Nano Bonds Increase Raw Strength of Fireproof Concretes August 18th, 2014

Silicene Labs Announces the Launch of Patent-Pending, 2D Materials Composite Index™ : The Initial 2D Materials Composite Index™ for Q2 2014 Is: 857.3; Founders Include World-Renowned Physicist and Seasoned Business and IP Professionals July 24th, 2014

NanoNews-Digest
The latest news from around the world, FREE





  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More














ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE