Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

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

Tokyo Institute of Technology research: Antiaromatic molecule displays record electrical conductance July 19th, 2017

Harnessing light to drive chemical reactions July 19th, 2017

Nanoparticles could spur better LEDs, invisibility cloaks July 19th, 2017

A firefly's flash inspires new nanolaser light July 18th, 2017

Govt.-Legislation/Regulation/Funding/Policy

Here's a tip: Indented cement shows unique properties: Rice University models reveal nanoindentation can benefit crystals in concrete July 20th, 2017

Harnessing light to drive chemical reactions July 19th, 2017

Nanoparticles could spur better LEDs, invisibility cloaks July 19th, 2017

National Space Society Governor Scott Pace Named to National Space Council as Executive Secretary July 18th, 2017

Discoveries

Here's a tip: Indented cement shows unique properties: Rice University models reveal nanoindentation can benefit crystals in concrete July 20th, 2017

Tokyo Institute of Technology research: Antiaromatic molecule displays record electrical conductance July 19th, 2017

Harnessing light to drive chemical reactions July 19th, 2017

Nanoparticles could spur better LEDs, invisibility cloaks July 19th, 2017

Materials/Metamaterials

Carbon displays quantum effects July 13th, 2017

Meniscus-assisted technique produces high efficiency perovskite PV films July 7th, 2017

ANU invention may help to protect astronauts from radiation in space July 3rd, 2017

Brookhaven Scientists Study Role of 'Electrolyte Gating' in Functional Oxide Materials July 3rd, 2017

Announcements

Here's a tip: Indented cement shows unique properties: Rice University models reveal nanoindentation can benefit crystals in concrete July 20th, 2017

Tokyo Institute of Technology research: Antiaromatic molecule displays record electrical conductance July 19th, 2017

Harnessing light to drive chemical reactions July 19th, 2017

Nanoparticles could spur better LEDs, invisibility cloaks July 19th, 2017

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

Here's a tip: Indented cement shows unique properties: Rice University models reveal nanoindentation can benefit crystals in concrete July 20th, 2017

Tokyo Institute of Technology research: Antiaromatic molecule displays record electrical conductance July 19th, 2017

Harnessing light to drive chemical reactions July 19th, 2017

A firefly's flash inspires new nanolaser light July 18th, 2017

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

Here's a tip: Indented cement shows unique properties: Rice University models reveal nanoindentation can benefit crystals in concrete July 20th, 2017

National Space Society Governor Scott Pace Named to National Space Council as Executive Secretary July 18th, 2017

Researchers revolutionize vital conservation tool with use of gold nanotechnology and lasers: Cryopreservation study results have sweeping implications for wildlife conservation and human health July 15th, 2017

Nature-inspired material uses liquid reinforcement: Rice U. nanoengineers create liquid-solid composites using clues from nature July 11th, 2017

Construction

Here's a tip: Indented cement shows unique properties: Rice University models reveal nanoindentation can benefit crystals in concrete July 20th, 2017

Russian scientists create new system of concrete building structures: Sientists of Peter the Great Saint-Petersburg Polytechnic University developed a new construction technology April 24th, 2017

Next-gen steel under the microscope March 18th, 2017

Graphene foam gets big and tough: Rice University's nanotube-reinforced material can be shaped, is highly conductive February 13th, 2017

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