We take "self-assembly" for granted when it is carried out by the biopolymers which are our hair, teeth, or skin. But when scientists devise new ways for molecules to self assemble into new materials, it is an important achievement.

Researchers with the Macromolecules and Interfaces Institute (MII www.mii.vt.edu) at Virginia Tech report such a development in the online issue for the Journal of the American Chemical Society, in the article, "Aggregation of Rod-Coil Block Copolymers Containing Rigid Polyampholyte Blocks in Aqueous Solution" (10.1021/ja070422+) and at the 233rd National Meeting of the American Chemical Society (ACS) in Chicago, March 25-29.

S. Richard Turner, MII director and research professor of chemistry at Virginia Tech, and Min Mao, a Ph.D. candidate in polymer chemistry, report the synthesis of a new family of charged, rod-like block copolymers. Only as long as a fraction of the diameter of human hair, the tiny rods can be either positive or negative, or can have alternating positive and negative charges along the backbone. The rods self-assemble and the aggregated structures are remarkable stable in saline solution, Turner said.

"The early results of this study suggest that these charged polymers self-assemble by like-charge interactions similar to such natural polymers as DNA," said Turner. "The stable self-assembled structures could have potential applications in drug delivery and gene delivery systems."

But more immediate, "These unique block copolymers can be instructive models in understanding the forces that lead to the dense packing of DNA when complexed with viruses and other polymers," he said.

The ACS poster, "Stimulus Responsive Aggregation in Aqueous Solution of a Novel Rod-Coil Type Double Hydrophilic Block Copolymer Containing Rigid Strictly Alternating Polyampholytes" (PMSE 314), will be presented from 6 to 8 p.m. on Tuesday, March 27, at the Hyatt Regency Chicago Riverside Center as part of the joint PMSE – Polymer poster session.

Mao, who is a graduate research assistant in polymer chemistry and physics at Virginia Tech, received his bachelor of science in chemistry and master of science in surfactant, colloid, and surface science from Peking University, Beijing.

Written from a news release by Virginia Tech.