Lab researches new resins for light-based 3D printing

A team from the Lawrence Livermore National Laboratory (LLNL) has simulated the networking of 3D-printed polymer networks. This is an important step in the development of new functional resins for light-based 3D printing techniques, including two-photon lithography (TPL). and volumetric additive manufacturing (VAM).

The team used molecular dynamics simulations to study, at the microscopic level, the kinetics and topology of three different molecules from the same reactive group (acrylate) but containing different non-reactive components. The researchers found that differences in the dynamics and structure of the resulting crosslinked polymers made using the TPL and VAM processes were due to differences in the non-reactive parts of the molecules. The research appears in the October 15 issue of Journal of Physical Chemistry B. and is offered online as an additional cover.

The researchers said the insights gained from the study will open the door to rationally designed photoresists and help them in their quest for new custom photosensitive resins that can push the boundaries of TPL and LLNL developed VAM. These techniques create 3D objects by projecting structured light into liquid resins, causing them to harden in the desired locations within seconds. The resins used in these processes often contain different molecules with the same reactive functional groups and their formulation is based on trial and error methods, with the results being treated as trade secrets.

“Our combination of molecular dynamics simulations and mathematical graph theory enables us to modify or disrupt the chemistry and physics of molecules that serve as building blocks in AM techniques such as TPL and VAM and to see the effects on the resulting polymer” explained John Karnes. the lead author of the paper. “Since we can see every atom in these simulations, we begin to develop an intuition that bridges the gap between microscopic network topology and macroscopic behavior, such as understanding the relationship between intramolecular loops or cycles and the point at which the liquid resin gels form the solid printed part. ”

LLNL materials scientist Jürgen Biener said the team continues to work by researching longer length and time scales, simulating mechanical tests of printed parts, and modeling other types of polymerization that are of interest to LLNL.

New materials expand volumetric 3D printing

More information:
John J. Karnes et al. On the Network Topology of Cross-linked Acrylate Photopolymers: A Molecular Dynamics Case Study, Das Journal of Physical Chemistry B. (2020). DOI: 10.1021 / acs.jpcb.0c05319

Provided by the Lawrence Livermore National Laboratory