Two-dimensional, "sheet-like" nanostructures are commonly employed in biological systems such as cell membranes, and their unique properties have inspired interest in materials such as graphene. Now, Berkeley Lab scientists have made the largest two-dimensional polymer crystal self-assembled in water to date. This entirely new material mirrors the structural complexity of biological systems with the durable architecture needed for membranes or integration into functional devices.
These self-assembling sheets are made of peptoids, engineered polymers that can flex and fold like proteins while maintaining the robustness of manmade materials. Each sheet is just two molecules thick yet hundreds of square micrometers in area—akin to 'molecular paper' large enough to be visible to the naked eye.
Zuckermann and coauthor Christian Kisielowski reached another first by using the TEAM 0.5 microscope at the National Center for Electron Microscopy (NCEM) to observe individual polymer chains within the peptoid material, confirming the precise ordering of these chains into sheets and their unprecedented stability while being bombarded with electrons during imaging.
"The design of nature-inspired, functional polymers that can be assembled into membranes of large lateral dimensions marks a new chapter for materials synthesis with direct impact on Berkeley Lab's strategically relevant initiatives such as the Helios project or Carbon Cycle 2.0," said NCEM's Kisielowski. "The scientific possibilities that come with this achievement challenge our imagination, and will also help move electron microscopy toward direct imaging of soft materials."
"This new material is a remarkable example of molecular biomimicry on many levels, and will no doubt lead to many applications in device fabrication, nanoscale synthesis and imaging," Zuckermann added. ###
This research is reported in a paper titled, "Free floating ultra-thin two-dimensional crystals from sequence-specific peptoid polymers," appearing in the journal Nature Materials and available in Nature Materials online. Co-authoring the paper with Zuckermann and Kisielowski were Ki Tae Nam, Sarah Shelby, Phillip Choi, Amanda Marciel, Ritchie Chen, Li Tan, Tammy Chu, Ryan Mesch, Byoung-Chul Lee and Michael Connolly.
This work at the Molecular Foundry was supported by DOE's Office of Science and the Defense Threat Reduction Agency.
The Molecular Foundry is one of the five DOE Nanoscale Science Research Centers (NSRCs), premier national user facilities for interdisciplinary research at the nanoscale. Together the NSRCs comprise a suite of complementary facilities that provide researchers with state-of-the-art capabilities to fabricate, process, characterize and model nanoscale materials, and constitute the largest infrastructure investment of the National Nanotechnology Initiative. The NSRCs are located at DOE's Argonne, Brookhaven, Lawrence Berkeley, Oak Ridge and Sandia and Los Alamos National Laboratories. For more information about the DOE NSRCs, please visit nano.energy.gov.
Berkeley Lab is a U.S. Department of Energy national laboratory located in Berkeley, California. It conducts unclassified scientific research and is managed by the University of California. Visit our website at www.lbl.gov.
Contact: Aditi Risbud firstname.lastname@example.org 510-486-4861 DOE/Lawrence Berkeley National Laboratory