PMSE 292 |
| We have used hydrogen-bonded multilayers of poly(N-vinyl pyrrolidone) (PVPON) and poly(methacrylic acid) (PMAA) as precursors for producing surface-bound hydrogels, and studied their pH-dependent swelling and protein/dye uptake behavior using in situ ATR-FTIR (attenuated total reflection Fourier transform infrared spectroscopy) and in situ ellipsometry. The hydrogels were produced by selective chemical crosslinking between PMAA units using carbodiimide chemistry and ethylenediamine (EDA) as a crosslinking reagent, followed by complete removal of PVPON from the film attained by exposing the film to pH=7.5. As shown by in situ ellipsometry, hydrogels exhibit distinctive polyampholytic swelling as a function of pH. The pH-switching of hydrogel swelling was fast and reversible and the degree of hydrogel swelling could be also controlled by varying the time allowed for crosslinking. The produced hydrogels were capable to reversibly absorb and release small molecules or macromolecules of different charge and this was demonstrated by using Rhodamine 6G dye, bromophenol blue dye, heparin, lysozyme, ferritin, concanavalin A and BSA. These systems might find applications for controlled delivery or separation of chemicals employing surfaces. |
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Joint PMSE/POLY Poster Session
6:00 PM-8:00 PM, Tuesday, 12 September 2006 Moscone Center -- Hall D, Poster
Sci-Mix
Division of Polymeric Materials: Science & Engineering |