New computer design methods pave the way for scientists to design and assemble bundles of peptides. Peptides are compounds of amino acids, organic substances that make up proteins. These new design methods allow scientists to determine the desired size, shape, and display of the chemical groups in the peptides. Scientists can then link these customizable building blocks, called bundlemers, to produce a huge array of polymers. Linking identical bundlemers together in different ways allows fine tuning of polymer stiffness and properties. For example, scientists can make exotically rigid rod-like polymers that could be used to design new materials with a wide range of applications.
Bundlemers provide scientists with almost limitless control of the structure and function of polymers down to the nanometer scale. A nanometer is about 100,000 times smaller than the width of a human hair. Scientists build these polymers from simple building blocks made of simple, environmentally friendly materials. These features give polymers made of bundlemers enormous potential in applications such as super-strong, environmentally friendly materials. The new method also advances the broader field of nanoscience.
Biomolecules have a wide range of desirable features that would be useful in artificial materials. These include unusual strength and resiliency. Placing these features into polymers is a key goal in the design of highly sophisticated soft materials. Scientists used natural and modified amino acids to design and create modular, functional building blocks. The researchers call these building blocks bundlemers. This design process allowed the scientists to program how the building blocks could be precisely, chemically linked together to form rigid or flexible polymer chains. The process controls the location of chemical function and chain properties separately. The rigid bundle chains are over one hundred times more rigid than other polymers and one-dimensional assemblies with similar mass and length. The polymer materials also can be tuned to respond to changes in temperature. This allows the polymer materials to be dissolved and re-assembled at desired temperatures. All of these capabilities enable new types of materials to be programed to perform specific tasks across multiple dimensions.
Primary funding was provided by the Department of Energy Office of Science, Office of Basic Energy Sciences. Support for neutron-scattering experiments was provided by the Department of Commerce National Institute of Standards and Technology. Additional facilities and instrument support were provided by the National Science Foundation, the National Institutes of Health (NIH), and the University of Delaware NIH Centers of Biomedical Research Excellence. Individual researchers also received support from NSF and the University of Delaware.