Study unveils how soft materials react to deformation at molecular level

Source: Xinhua| 2019-06-26 06:03:13|Editor: Mu Xuequan
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CHICAGO, June 25 (Xinhua) -- Researchers at the University of Illinois (UI) recently challenged previous assumptions regarding polymer behavior with newly developed laboratory techniques that measure polymer flow at the molecular level.

According to a news release posted on UI's website on Monday, the researchers simultaneously measured multiscale deformations by combining traditional tools for measuring stress and deformation at the macroscopic level with a technique called neutron scattering to observe the structure at the molecular scale in the lab.

They found something unexpected.

"With simultaneous neutron scattering and flow measurements, we are able to directly correlate structure and mechanical properties with a time resolution on the order of milliseconds," said study co-author Katie Weigandt, a researcher from the National Institute of Standards and Technology Center for Neutron Science. "This approach has led to fundamental understanding in a wide range of nanostructured complex fluids, and in this work, validates new approaches to making polymer flow measurements."

"Previous research had assumed that the amount of applied deformation at the macroscale is what soft materials experience at the microscale," said Johnny Ching-Wei Lee, a graduate student and study co-author. "But the neutron-scattering data from our study clearly shows that it is the deformation that can be recovered that matters because it dictates the whole response, in terms of macroscopic flow."

The researchers said this development will help rectify several poorly understood phenomena in polymers research, such as why polymers expand during three-dimensional printing processes.

The research brings key insights to the long-standing challenge in soft condensed matter, and the team said the established structure-property-processing relationships could provide a new design criterion for soft materials.

This approach may lead to the design of new biomedical, industrial and environmental applications - from polymers that aid in blood clotting to materials that more efficiently extract oil and gas from wells.

The findings have been published in the journal Physical Review Letters.