Nanotechnology Now

Our NanoNews Digest Sponsors
Heifer International

Wikipedia Affiliate Button

Home > Press > Weak hydrogen bonds key to strong, tough infrastructure: Rice University lab simulates polymer-cement composites to find strongest, toughest materials

Rice University scientists probing the interfacial interactions of polymer (blue) and cement (yellow) discovered the right mix of hydrogen bonds is critical to making strong, tough and ductile composite materials for infrastructure. Computer simulations like that in the illustration measured the strength of the bonds as hard cement slides past the soft polymer in a layered composite, which mimics the structure nacre, seen in the background.

CREDIT
Probhas Hundi/Multiscale Materials Laboratory
Rice University scientists probing the interfacial interactions of polymer (blue) and cement (yellow) discovered the right mix of hydrogen bonds is critical to making strong, tough and ductile composite materials for infrastructure. Computer simulations like that in the illustration measured the strength of the bonds as hard cement slides past the soft polymer in a layered composite, which mimics the structure nacre, seen in the background. CREDIT Probhas Hundi/Multiscale Materials Laboratory

Abstract:
The right mix of hydrogen bonds in polymer and cement composites is critical to making strong, tough and ductile infrastructure material, according to Rice University scientists who want to mimic the mechanics of mother-of-pearl and similar natural composites with synthetic materials.

Weak hydrogen bonds key to strong, tough infrastructure: Rice University lab simulates polymer-cement composites to find strongest, toughest materials

Houston, TX | Posted on January 29th, 2018

Seashells made of mother-of-pearl, aka nacre, get their remarkable properties from overlapping micron-sized, mineralized plates held together by a soft matrix. This structure can be approached by cement and polymer composites that may, for instance, make better earthquake-resistant concrete, according to Rouzbeh Shahsavari, an assistant professor of civil and environmental engineering.

The Rice lab ran more than 20 computer simulations of how polymers and cement molecules come together at the nanoscale and what drives their adhesion. The researchers showed that the proximity of oxygen and hydrogen atoms is the critical factor in forming a network of weak hydrogen bonds that connects soft and hard layers. Common polyacrylic acid (PAA) proved best at binding the overlapping layers of cement crystals with an optimal overlap of about 15 nanometers.

"This information is important to make the best synthetic composites," said Shahsavari, who ran the project with Rice graduate student Navid Sakhavand. "A modern engineering approach to these materials will have a large impact on society, especially as we build new and replace aging infrastructure."

The lab's results appear in Applied Physics Letters.

While engineers understand that adding polymers improves cement by blocking the damaging effects of "aggressive" ions that invade its pores, details about how the materials interact at the molecular scale have remained unknown, Shahsavari said. To find out, the researchers modeled composites with PAA as well as polyvinyl alcohol (PVA), both soft matrix materials that have been used to improve cement.

They discovered that the two different oxygen atoms in PAA (as opposed to one in PVA) allowed it to receive and donate ions as it bonded with hydrogen in the crystals of tobermorite cement. Oxygen in PAA had eight ways to bond with hydrogen (six for PVA) and could also participate in salt bridging between the polymer and cement, which makes the bonding network even more complex.

The researchers tested their simulated structures by sliding layers of polymer and cement against each other and found that complexity allowed the bonds between PAA and cement to break and reconnect more frequently as the material was stressed, which significantly increases its toughness, the ability to deform without fracturing. This allowed the researchers to determine the optimum overlap between cement crystals.

"In contrast to the common intuition that hydrogen bonds are weak, when the right number of them -- the optimum overlap -- cooperate, they provide sufficient connectivity in the composite to confer high strength and high toughness," Shahsavari said. "From an experimental standpoint, this can be done by carefully tuning and controlling the addition of the polymers with the right molecular weight while controlling cement mineral formation. Indeed, a recent experimental paper by our colleagues showed a proof of concept toward this strategy."

###

The National Science Foundation (NSF) supported the research. Supercomputing resources were supplied by Rice's NSF-supported DAVinCI supercomputer administered by the Center for Research Computing and procured in partnership with Rice's Ken Kennedy Institute for Information Technology.

####

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 3,970 undergraduates and 2,934 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 quality of life and for lots of race/class interaction and No. 2 for happiest students 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 .

Follow Rice News and Media Relations via Twitter @RiceUNews

For more information, please click here

Contacts:
David Ruth

713-348-6327

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 Laboratory (Shahsavari Lab):

George R. Brown School of Engineering:

Rice Department of Civil and Environmental Engineering:

Rice Department of Materials Science and NanoEngineering:

Related News Press

News and information

uSEE breakthrough unlocks the nanoscale world on standard biology lab equipment August 16th, 2019

Optofluidic chip with nanopore 'smart gate' developed for single molecule analysis: Programmable device enables on-demand delivery of individual biomolecules with feedback-controlled gating for high-throughput analysis August 16th, 2019

ULVAC Launches Revolutionary PZT Piezoelectric Thin-film Process Technology and HVM Solution for MEMS Sensors/Actuators: Enabling Reliable, High-quality Film Production for Next Generation Devices August 16th, 2019

RIT to upgrade Semiconductor and Microsystems Fabrication Laboratory through $1 million state grant: Upgrades to clean room will enhance university’s research capabilities in photonics, quantum technologies and smart systems August 16th, 2019

Govt.-Legislation/Regulation/Funding/Policy

uSEE breakthrough unlocks the nanoscale world on standard biology lab equipment August 16th, 2019

Optofluidic chip with nanopore 'smart gate' developed for single molecule analysis: Programmable device enables on-demand delivery of individual biomolecules with feedback-controlled gating for high-throughput analysis August 16th, 2019

Damaged hearts rewired with nanotube fibers: Texas Heart doctors confirm Rice-made, conductive carbon threads are electrical bridges August 14th, 2019

You're not so tough, h-BN: Rice University chemists find new path to make strong 2D material better for applications August 14th, 2019

Possible Futures

uSEE breakthrough unlocks the nanoscale world on standard biology lab equipment August 16th, 2019

ULVAC Launches Revolutionary PZT Piezoelectric Thin-film Process Technology and HVM Solution for MEMS Sensors/Actuators: Enabling Reliable, High-quality Film Production for Next Generation Devices August 16th, 2019

RIT to upgrade Semiconductor and Microsystems Fabrication Laboratory through $1 million state grant: Upgrades to clean room will enhance university’s research capabilities in photonics, quantum technologies and smart systems August 16th, 2019

Probing the Origin of Alzheimer’s . . . with Transistors: Novel high-sensitivity detector could aid in early diagnosis August 15th, 2019

Discoveries

uSEE breakthrough unlocks the nanoscale world on standard biology lab equipment August 16th, 2019

Optofluidic chip with nanopore 'smart gate' developed for single molecule analysis: Programmable device enables on-demand delivery of individual biomolecules with feedback-controlled gating for high-throughput analysis August 16th, 2019

Probing the Origin of Alzheimer’s . . . with Transistors: Novel high-sensitivity detector could aid in early diagnosis August 15th, 2019

Damaged hearts rewired with nanotube fibers: Texas Heart doctors confirm Rice-made, conductive carbon threads are electrical bridges August 14th, 2019

Materials/Metamaterials

You're not so tough, h-BN: Rice University chemists find new path to make strong 2D material better for applications August 14th, 2019

A modified device fabrication process achieves enhanced spin transport in graphene August 6th, 2019

Rice lab produces simple fluorescent surfactants: Compounds show promise for use in medicine, manufacturing August 5th, 2019

Wood You Like Some Fresh Water? New treatment for wood makes a membrane to extract fresh water August 5th, 2019

Announcements

uSEE breakthrough unlocks the nanoscale world on standard biology lab equipment August 16th, 2019

Optofluidic chip with nanopore 'smart gate' developed for single molecule analysis: Programmable device enables on-demand delivery of individual biomolecules with feedback-controlled gating for high-throughput analysis August 16th, 2019

ULVAC Launches Revolutionary PZT Piezoelectric Thin-film Process Technology and HVM Solution for MEMS Sensors/Actuators: Enabling Reliable, High-quality Film Production for Next Generation Devices August 16th, 2019

RIT to upgrade Semiconductor and Microsystems Fabrication Laboratory through $1 million state grant: Upgrades to clean room will enhance university’s research capabilities in photonics, quantum technologies and smart systems August 16th, 2019

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

uSEE breakthrough unlocks the nanoscale world on standard biology lab equipment August 16th, 2019

Optofluidic chip with nanopore 'smart gate' developed for single molecule analysis: Programmable device enables on-demand delivery of individual biomolecules with feedback-controlled gating for high-throughput analysis August 16th, 2019

Probing the Origin of Alzheimer’s . . . with Transistors: Novel high-sensitivity detector could aid in early diagnosis August 15th, 2019

Damaged hearts rewired with nanotube fibers: Texas Heart doctors confirm Rice-made, conductive carbon threads are electrical bridges August 14th, 2019

Construction

Dashing the dream of ideal 'invisibility' cloaks for stress waves June 7th, 2019

ZEN gets $1m grant for graphene-enhanced concrete project May 12th, 2019

Lightweight metal foams become bone hard and explosion proof after being nanocoated March 14th, 2019

A Comprehensive Guide: The Future of Nanotechnology September 13th, 2018

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



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project