Our work on
Sequence-Directed Assembly of Organic Nanostructures is implementing new strategies for the synthesis and application of heteropolymeric nanostructures in which functional side chains display unique ordering, in terms of both sequence along the polymer chain and three-dimensional arrangement in space. The focus of Thrust 2 is directed to amide-based organic nanostructures. The secondary amide group is an attractive subunit for building nanostructures because it is very stable chemically. In addition, the secondary amide group can both donate and accept hydrogen bonds, which specify and stabilize particular backbone conformations (shapes). Use of amide-based backbones permits introduction of a wide-range of chemical functionalities via existing precursor materials (amino acids). The nanostructures we target open new frontiers in fundamental nanoscience by combining the properties of rigid rods with unique patterns of surface functionality, and they are expected to enable a variety of technological advances. The interfacial properties and propensity of these organic nanorods to form mesophases (e.g., liquid crystals) is being explored through a combination of experiment, liquid state theory and Monte Carlo/molecular dynamics simulation. The efforts of Thrust 2 are organized around several long-term goals of importance to society, including new strategies for molecular and cellular biosensing, new types of antimicrobial surfaces, new approaches for solubilizing carbon nanotubes, and new techniques for packaging and manipulating DNA for sequencing and gene delivery.
