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

Assistant Professors Verena Martinez Outschoorn and Liang Yang of the Department of Physics at the University of Illinois at Urbana-Champaign have each been selected for 2017 NSF CAREER Awards. The Faculty Early Career Development (CAREER) Award of the National Science Foundation is conferred annually in support of junior faculty who exemplify the role of teacher-scholars by integrating outstanding research with excellent education. Receipt of this honor also reflects great promise for a lifetime of leadership within recipients’ respective fields.

Mason says, “there are so few of us, people get the impression that we are like unicorns – either non-existent or magical.” We are far from non-existent, but I find women of color to be quite magical. However, as Jesse Williams says, “Just because we’re magic, doesn’t mean we’re not real.”

  • Outreach

It’s up to you and your team to save the free world from evil forces plotting its destruction, and you have precisely 60 minutes to do it. You must find out what happened to Professor Schrödenberg, a University of Illinois physicist who disappeared after developing a top-secret quantum computer that can crack any digital-security encryption code in the world.  Unfortunately, the previous groups of special agents assigned to the case disappeared while investigating the very room in which you now find yourself locked up, Schrödenberg’s secret lab.

LabEscape is a new science-themed escape room now open at Lincoln Square Mall in Urbana, testing the puzzle-solving skills of groups of up to six participants at a time. Escape rooms, a new form of entertainment cropping up in cities across the U.S. and around the globe, provide in-person mystery-adventure experiences that have been compared to living out a video-game or movie script. A team of participants is presented with a storyline and locked into a room with only one hour to find and decipher a sequence of interactive puzzles that will unlock the door and complete the mission. Two escape room businesses are already in operation in the area, C-U Adventures in Time and Space in Urbana and Brainstorm Escapes in Champaign.

 

  • Research
  • AMO/Quantum Physics
  • Condensed Matter Physics

Topological insulators, an exciting, relatively new class of materials, are capable of carrying electricity along the edge of the surface, while the bulk of the material acts as an electrical insulator. Practical applications for these materials are still mostly a matter of theory, as scientists probe their microscopic properties to better understand the fundamental physics that govern their peculiar behavior.

Using atomic quantum-simulation, an experimental technique involving finely tuned lasers and ultracold atoms about a billion times colder than room temperature, to replicate the properties of a topological insulator, a team of researchers at the University of Illinois at Urbana-Champaign has directly observed for the first time the protected boundary state (the topological soliton state) of the topological insulator trans-polyacetylene. The transport properties of this organic polymer are typical of topological insulators and of the Su-Schrieffer-Heeger (SSH) model.

Physics graduate students Eric Meier and Fangzhao Alex An, working with Professor Bryce Gadway, developed a new experimental method, an engineered approach that allows the team to probe quantum transport phenomena.