April 14, 2010 – Researchers from Berkeley Lab have developed a material dubbed "molecular paper," with properties that can be precisely tailored for applications such as chemical and biological detection.

2D "sheet-like" nanostructures are used in biological systems (e.g. membranes), with properties that have inspired further work in areas such as graphene. Ron Zuckermann and Ki Tae Nam with Berkeley Lab’s Molecular Foundry have created what they say is the largest-to-date 2D polymer crystal that spontaneously self-assembles in water, combining the structural complexity of biological systems with a durable architecture needed for membranes, or for integration into functional devices. The sheets — 2-molecules thick and hundreds of sq. molecules in area — are made of peptoids that can flex and fold like proteins.

Unlike a typical polymer, each "building block" of the nanosheet has what the researchers call "structural marching orders," suggesting its properties can be tailored to be application-specific — e.g., to control the flow of molecules, or serve as the platform for chemical and biological detection. The building blocks for peptoid polymers are also "cheap, readily available," and generate high yields, another advantage over other synthesis techniques.

"Our findings bridge the gap between natural biopolymers and their synthetic counterparts, which is a fundamental problem in nanoscience," stated Ronald Zuckermann, director of the biological nanostructures facility at Berkeley Labs’ Molecular Foundry. "We can now translate fundamental sequence information from proteins to a non-natural polymer, which results in a robust synthetic nanomaterial with an atomically-defined structure."

"The scientific possibilities that come with this achievement challenge our imagination, and will also help move electron microscopy toward direct imaging of soft materials," added paper coauthor Christian Kisielowski from the National Center for Electron Microscopy (NCEM). The group also achieved another landmark by observing individual polymer chains within the peptoid material, confirming the chains’ ordering into sheets and stability during imaging.

Their work has been published in Nature Materials.