New Theory Explains Nonlinear Stretching in Rubbery Materials


2/1/2007 12:00 AM

Professor of Physics Paul Goldbart, in collaboration with Xiangjun Xing (Syracuse) and Leo Radzihovsky (Colorado), has solved a theory problem that has puzzled physicists since the 1940s (Phys. Rev. Lett. 98, 075502 [2007]).

Measuring the force produced by stretching a rubber band to its limits is easy, but the standard theory of rubbery materials cannot predict this force.

When they are not stretched too much, rubbery materials act as simple springs, obeying Hooke's law. Thus, a 10-percent increase in stretching force will extend a typical rubber band 10 percent farther. But at greater stretching forces, that simple linear relation fails. The existence of the nonlinearity has long been known, but understanding its origins and developing a theory that correctly captures it "has been a challenge to the physics community for 60 years," said Goldbart.

By including the extra entropy associated with long length-scale motion while simultaneously coping with the essentially incompressible nature of rubbery materials, the researchers are now able to construct a theory that agrees with experiment, not only in the Hookean regime but also beyond—deep into the nonlinear regime. Read more...

Recent News

  • Accolades

Celia Elliott, Physics Illinois’ director of external affairs and special projects, has received the 2016 SPaRC Career Achievement Award, for her significant and sustained contributions throughout her career to the field of research administration at the University of Illinois at Urbana-Champaign. The award was presented by the campus’s Sponsored Programs and Research Compliance group on Friday, September 16, 2016, during the SPaRC Retreat at the I-Hotel in Urbana.
Elliott is widely recognized among the department’s faculty as the pivotal resource for all things pertaining to successful grant writing and administration.

  • Research
  • Condensed Matter Physics

Physics professor Taylor Hughes and mechanical science and engineering professor Gaurav Bahl of the University of Illinois at Urbana-Champaign are part of an interdisciplinary team that will study non-reversible sound wave propagation over the next four years, with a range of promising potential applications.

The National Science Foundation has announced a $2-million research award to the team, which includes University of Oregon physics professor Hailin Wang and Duke University electrical and computer engineering professor Steven Cummer. The grant is part of a broader $18-million NSF-funded initiative, the Emerging Frontiers in Research and Innovation (EFRI) program, supporting nine teams—a total of 37 researchers at 17 institutions—to pursue fundamental research in the area of new light and acoustic wave propagation, known as NewLAW.

  • In the Media

Edward Seidel, director of the National Center for Supercomputing Applications, was named interim vice president for research to succeed Lawrence Schook, a biomedical researcher who announced last spring that he would step down after more than five years to return to his research. Seidel will assume office Sept. 1, pending approval from UI trustees.

  • Accolades

Andrea Young, a physics professor at the University of California, Santa Barbara, has been awarded the 2016 McMillan Award for outstanding contributions in condensed matter physics. Named in memory of physicist William McMillan of the University of Illinois at Urbana-Champaign, the award is presented annually for distinguished research performed within five years of receiving a Ph.D.