We have advanced the methodologies that are available to access sophisticated block brush copolymers. Controlled polymerization chemistries allow for tuning of the length of the polymer backbone and the lengths of the side chain grafts, independently, to afford high degrees of control over the dimensions of these nanoscale objects. As one example, living radical and ring opening metathesis polymerization chemistries were combined to synthesize structures having a norbornene-based backbone and side chain grafts of polyisoprene and poly(tert-butyl acrylate) chain segments. Extensive characterization studies are revealing the well-defined structure and properties, shown by the AFM height image of the centipede-like cylindrically-shaped nanoscale macromolecules.

198

O O180.04 41

198

O N

0.150.81

O O( )

10 ONO O

( )10

O O( )

10 O N

O OH180.04 41

198

0.150.81

O O( )

10 O N

180.04

198

0.150.81

O O( )10

O N

PCy3RuPCy3

HPh

ClCl

[M]0/[I]0 = 200toluene, 1h Mn, GPC = 122 kDa

PDI = 1.13

ON

,

[M]0/[nitroxide]0/[I]0 = 1550/2.7/1120 oC, 32 h

(I: alkoxyamine)

Mn, GPC = 366 kDaPDI = 1.19

O O

ON

,

[M]0/[nitroxide]0/[I]0 = 1600/2.8/1122 oC, 24 h

(I: alkoxyamine)HClH2O-dioxane (1/9)

reflux, 12 h

Mn, GPC = 1410 kDaPDI = 1.23

Synthetic Methodology

Block Brush Copolymer Structure

Block Brush Copolymer Image

Cheng, C.; Qi, K.; Germack, D. S.; Khoshdel, E.; Wooley, K. L. Adv. Mater., 2007, 19(19), 2830-2835

Controlling the Dimensions of Nanoscale Polymer Objects

Karen L. Wooley, Washington University, DMR 0451490

Incorporating Function into Degradable Polymer Materials

Karen L. Wooley, Washington University, DMR 0451490

Because of the significant interest in synthetic polymer systems with increasing degrees of complexity, we have focused attention upon the development of chemistries for the conversion of polyester backbones into functional materials. Polyesters are of great importance as degradable materials, but they lack reactive chemical units for derivatization along the backbone. Facile conjugation strategies upon ketone-bearing poly(-caprolactone) were studied as general methodologies. Sequential vs. single-step approaches were explored for the introduction of grafting chains and fluorophoric groups. These initial results are leading to advanced labeling of polyesters and modification of their structures and properties, for their adaptation as scaffolds for biomedical applications and also for environmental remediation purposes.

Sequential vs. Single-step Strategies for the Multiple Functionalization of

Degradable Polyesters

Van Horn, B. A.; Iha, R. K.; Wooley, K. L. Macromolecules, 2008, 41(5), 1618-1626

The Power of Nanotechnology for Attracting Young, Diverse Students to Science Education Activities

Karen L. Wooley, Washington University, DMR 0451490

An after school program, “The Cutting Edge of Nanotechnology: The interplay between Robotics and Chemistry”, was created, in partnership with Dr. Kenya T. Powell (a postdoctoral associate), Ms. Betsy Ceresia (a 6-8 grade science teacher) and Ms. Kathie Reuter (a consultant) for 12 6th-8th grade students at the Hoech Middle School of the Ritenour School District in St. Louis, MO, to teach the students about nanotechnology through hands-on activities. The students met after school, twice per week for an entire semester, during which the students worked on projects in a research-like manner, maintained weekly journals, performed related chemistry experiments, and designed, built, and programmed a robot.

As shown in the photo, students learned about the concept of atomic force microscopy (AFM) by building a macroscopic version that operated on similar principles as does AFM.