New Polymer films for Sensing and Separations

Gregory Baker and Merlin Bruening
Polymer films can provide selective interfaces for both sensing and separations applications. For example, selective polymer films on nanobalances serve as sensors for specific compounds such as warfare agents. In separations, selective films allow rapid separation of very similar compounds, such as chiral molecules. We are creating polymer films with unique structures so that they will rapidly and selectively interact with analyte molecules. This work involves both imprinted polymer films and "giant" polymer brushes.
Polymer films can provide selective interfaces for both sensing and separations applications. For example, selective polymer films on nanobalances serve as sensors for specific compounds such as warfare agents. In separations, selective films allow rapid separation of very similar compounds, such as chiral molecules. We are creating polymer films with unique structures so that they will rapidly and selectively interact with analyte molecules. This work involves both imprinted polymer films and "giant" polymer brushes.
In imprinting of polymers, template molecules interact with functional monomers, which are then polymerized with an excess of cross-linking agent. Removal of the template leaves a selective cavity as shown. One challenge in using these films is the slow equilibration between analyte molecules and imprinted cavities. To overcome this challenge, we prepared ultrathin, cross-linked films by room-temperature atom-transfer radical polymerization (ATRP) from a surface. We are currently expanding the method so that we can polymerize functional monomers and imprint films.
We are also preparing giant polymer brushes that can be deposited in capillaries as shown in the figure. Preparation of micron-long polymer brushes occurs by ATRP with water as a solvent, because water greatly accelerates the polymerization. These "giant" brushes can be readily derivatized with biological or small molecules for specificity.

 

References:
Controlled Synthesis of Cross-linked Ultrathin Polymer Films by using Surface-initiated Atom Transfer Radical Polymerization, W.X. Huang et al., Angew.Chemie Int. Edit. 40, 1510 (2001).

Functionalization of surfaces by water-Accelerated Atom-Transfer Radical Polymerization of Hydroxyethylmethacrylate and Subsequent Derivatization, W.X. Huang et al., Macromolecules 35, 1175 (2002).