简介: |
The attachment of polymer thin films on solid materials is an effective way to tailor the chemical and physical properties of the surface layer, and to introduce functions to materials. We have developed two methods for the immobilization of ultrathin polymer films. In the first method, a heterobifunctional crosslinking agent was used to covalently immobilize a monolayer of polymers.1 A variety of polymers were successfully immobilized with thickness ranging from a few to over a hundred Ångstroms. Polymer thin films and microwell arrays were also constructed with precise controls over the thickness and topography of the structures.2,3 The second method is based on photochemically-induced direct attachment of polymer thin films by spin coating and UV irradiation.4
We have fabricated polymer thin films that acted as responsive coatings which controlled surface wettability and swelling toward external stimuli such as solvents, pH, and metal ions.5 Polymer nanostructures were created by employing the technique of dip-pen nanolithography to induce local swelling in the films. Mass and modulus changes were investigated as proton incorporated into the films from aqueous solutions of different pH’s. Results were detected by measuring the resonant frequency shifts and dissipation of piezoelectric quartz crystals. Large frequency shifts were observed upon exposure to acidic solutions.5 The changes were rapidly and the effect was reversible.
The surface chemistry was employed to introduce molecular recognition in polymer thin films. Molecularly imprinted polymer6 films that are capable of binding adenine and derivatives were prepared. The synthesis, characterization and rebinding studies of these films will be presented.
1. M. Yan, Polym. News, 27:6-12 (2001).
2. M. Bartlett, M. Yan, Adv. Mater., 13:1449-1451 (2001).
3. M. Yan, M. Bartlett Nano Lett., 13:275-278 (2002).
4. M. Yan, B. Harnish, Adv. Mater., 15:244-248 (2003).
5. B. Harnish, J. Robinson, Z. Pei, O. Ramstrom, M. Yan, Chem. Mater., 17:4092-4096 (2005). Yan, M.; Ramstrom, O. Eds. Molecularly Imprinted Materials: Science and Technology, CRC Press/Dekker, 2005. |
