Nanotechnology Now

Our NanoNews Digest Sponsors



Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Answer to saliva mystery has practical impact

Stretching a moistened material contained in a strip on the leading edge of disposable razors demonstrates a long-mysterious phenomenon that causes some fluids to form beads while others do not. Whereas beads form when a bit of saliva is stretched, they do not form when the material on the razor strip is stretched. Researchers have learned why the beading occurs, which could help improve industrial processes and for administering drugs in "personalized medicine." (Gareth H. McKinley/MIT)
Stretching a moistened material contained in a strip on the leading edge of disposable razors demonstrates a long-mysterious phenomenon that causes some fluids to form beads while others do not. Whereas beads form when a bit of saliva is stretched, they do not form when the material on the razor strip is stretched. Researchers have learned why the beading occurs, which could help improve industrial processes and for administering drugs in "personalized medicine." (Gareth H. McKinley/MIT)

Abstract:
Bead formation model could be boon for plastics, pharmaceuticals

Answer to saliva mystery has practical impact

Houston, TX | Posted on June 11th, 2010

Researchers at Rice University, Purdue University and the Massachusetts Institute of Technology have solved a long-standing mystery about why some fluids containing polymers -- including saliva -- form beads when they are stretched and others do not.

The findings are published online this week in the journal Nature Physics.

Study co-author Matteo Pasquali, professor in chemical and biomolecular engineering at Rice, said the study answers fundamental scientific questions and could ultimately lead to improvements as diverse as ink-jet printing, nanomaterial fiber spinning and drug dispensers for "personalized medicine."

Co-author Osman Basaran, Purdue's Burton and Kathryn Gedge Professor of Chemical Engineering, said, "Any kindergartner is familiar with this beading phenomenon, which you can demonstrate by stretching a glob of saliva between your thumb and forefinger. The question is, 'Why does this beading take place only in some fluids containing polymers but not others?'"

Pasquali said, "In answering the question about why some fluids do this and others do not, we are addressing everyday processes that apply to fiber and droplet formation, not just in multibillion-dollar industrial plants but also in fluids produced in living cells."

Saliva and other complex "viscoelastic" fluids like shaving cream and shampoo contain long molecules called polymers. When a strand of viscoelastic fluid is stretched, these polymers can cause a line of beads to form just before the strand breaks.

Pasquali said the explanation for why some viscoelastic fluids form beads and others do not was decades in the making. The origins of the work can be traced to Pasquali's and Basaran's doctoral research adviser, L.E. "Skip" Scriven of the University of Minnesota. Pasquali said Scriven worked out the basics of the competition between capillary, inertial and viscous forces in flows during the 1970s and 1980s. In the mid-1990s, during his doctoral research at Minnesota, Pasquali expanded on Scriven's earlier work to include the effects of viscoelasticity, which originates in liquid microstructures and nanostructures. Finally, Pasquali's former doctoral student, Pradeep Bhat, the lead author of the new study, took up the mantle nine years ago as a Ph.D. student in Pasquali's lab and continued working on the problem for the past three years as a postdoctoral researcher in Basaran's lab at Purdue.

Bhat, Basaran and Pasquali found that a key factor in the beading mechanism is fluid inertia, or the tendency of a fluid to keep moving unless acted upon by an external force.

Other major elements are a fluid's viscosity; the time it takes a stretched polymer molecule to "relax," or snap back to its original shape when stretching is stopped; and the "capillary time," or how long it would take for the surface of the fluid strand to vibrate if plucked.

"It turns out that the inertia has to be large enough and the relaxation time has to be small enough to form beads," Bhat said.

The researchers discovered that bead formation depends on two ratios: the viscous force compared with inertial force and the relaxation time compared with the capillary time.

Additional co-authors include Purdue graduate student Santosh Appathurai; Michael Harris, professor of chemical engineering at Purdue; and Gareth McKinley, professor of mechanical engineering at MIT.

####

About Rice University
Located in Houston, Rice University is consistently ranked one of America's best teaching and research universities. Known for its "unconventional wisdom," Rice is distinguished by its: size -- 3,279 undergraduates and 2,277 graduate students; selectivity -- 12 applicants for each place in the freshman class; resources -- an undergraduate student-to-faculty ratio of 5-to-1; sixth largest endowment per student among American private research universities; residential college system, which builds communities that are both close-knit and diverse; and collaborative culture, which crosses disciplines, integrates teaching and research, and intermingles undergraduate and graduate work.

For more information, please click here

Contacts:
Jade Boyd
Associate Director and Science Editor
Office of Public Affairs/News & Media Relations
Rice University
(office) 713-348-6778
(cell) 713-302-2447

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 News Press

News and information

NREL Announces New Center Directors to lead R&D, Analysis Efforts September 30th, 2014

Yale University and Leica Microsystems Partner to Establish Microscopy Center of Excellence: Yale Welcomes Scientists to Participate in Core Facility Opening and Super- Resolution Workshops October 20 Through 31, 2014 September 30th, 2014

Speed at its limits September 30th, 2014

Research mimics brain cells to boost memory power September 30th, 2014

Possible Futures

Air Forceís 30-year plan seeks 'strategic agility' August 1st, 2014

IBM Announces $3 Billion Research Initiative to Tackle Chip Grand Challenges for Cloud and Big Data Systems: Scientists and engineers to push limits of silicon technology to 7 nanometers and below and create post-silicon future July 10th, 2014

Virus structure inspires novel understanding of onion-like carbon nanoparticles April 10th, 2014

Local girl does good March 22nd, 2014

Academic/Education

Yale University and Leica Microsystems Partner to Establish Microscopy Center of Excellence: Yale Welcomes Scientists to Participate in Core Facility Opening and Super- Resolution Workshops October 20 Through 31, 2014 September 30th, 2014

Rice launches Center for Quantum Materials: RCQM will immerse global visitors in cross-disciplinary research September 30th, 2014

Biosensors Get a Boost from Graphene Partnership: $5 Million Investment Supports Dozens of Jobs and Development of 300mm Fabrication Process and Wafer Transfer Facility September 18th, 2014

Malvern technology delivers Malvern reliability in multi-disciplinary lab at Queen Mary University London September 9th, 2014

Nanomedicine

Speed at its limits September 30th, 2014

Ad-REIC vaccine: A magic bullet for cancer treatment September 30th, 2014

New Topical Hemostatic Agent: Neutral Self-Assembling Peptide Hydrogel September 30th, 2014

A Heartbeat Away? Hybrid "Patch" Could Replace Transplants: TAU researcher harnesses gold nanoparticles to engineer novel biocompatible cardiac patch September 30th, 2014

Discoveries

Research mimics brain cells to boost memory power September 30th, 2014

Ad-REIC vaccine: A magic bullet for cancer treatment September 30th, 2014

New Topical Hemostatic Agent: Neutral Self-Assembling Peptide Hydrogel September 30th, 2014

Chemical interactions between silver nanoparticles and thiols: A comparison of mercaptohexanol again September 30th, 2014

Materials/Metamaterials

Rice launches Center for Quantum Materials: RCQM will immerse global visitors in cross-disciplinary research September 30th, 2014

How things coil: Researchers discover that simulation technology designed for Hollywood can be used as a predictive tool for understanding fundamental engineering problems September 29th, 2014

Iranian Scientists Determine Grain Size, Minimize Time of Nanocomposite Synthesis September 29th, 2014

Nanoparticles Used to Improve Quality of Bone Cement September 29th, 2014

Announcements

Park Systems Announces Outsourced Analytical Services Including AFM Surface Imaging, Data Analysis and Interpretation September 30th, 2014

Ad-REIC vaccine: A magic bullet for cancer treatment September 30th, 2014

New Topical Hemostatic Agent: Neutral Self-Assembling Peptide Hydrogel September 30th, 2014

Chemical interactions between silver nanoparticles and thiols: A comparison of mercaptohexanol again September 30th, 2014

Research partnerships

Research mimics brain cells to boost memory power September 30th, 2014

'Pixel' engineered electronics have growth potential: Rice, Oak Ridge, Vanderbilt, Penn scientists lead creation of atom-scale semiconducting composites September 29th, 2014

Teijin Aramidís carbon nanotube fibers awarded with Paul Schlack prize: New generation super fibers bring wave of innovations to fiber market September 25th, 2014

Smallest-possible diamonds form ultra-thin nanothread September 25th, 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