Institut Charles Sadron News

New study of polymer welding featured on the cover of Physical Review Letters

A collaborative study involving researchers from the Institut Charles Sadron (ICS), Columbia University and Sandia National Laboratories has been published in Physical Review Letters, where it was selected as an Editors’ Suggestionand featured on the journal cover.

The work, “Molecular Insights on the Thermal Welding of Semicrystalline Polymers”, uses large-scale molecular dynamics simulations to investigate what happens at the molecular level when two polyethylene films are thermally welded. The simulations reveal how molecular orientation and entanglements evolve as the two polymer surfaces interdiffuse, and how these residual structures influence subsequent crystallization.

Remarkably, the researchers find that crystallization can amplify subtle molecular differences left behind by the welding process, producing a region of enhanced crystallinity around the weld interface. This provides new molecular-level insight into why welded semicrystalline polymers can develop structural and mechanical properties that differ from the surrounding material.

The study brings together the expertise of William S. Fall and Hendrik Meyer at the Institut Charles Sadron, Michele Valsecchi and Sanat K. Kumar at Columbia University, and Gary S. Grest at Sandia National Laboratories. 

Physical Review Letters 137, 098101 (2026). DOI: 10.1103/dbck-v8nm.