Molla Islam - Microgel-based etalon coated quartz crystal microbalances for detecting solution pH: The effect of Au overlayer thickness.

Version 1

      Publication Details (including relevant citation   information): Islam, Molla R., Johnson, Kai C. C.,   Serpe, Michael J., Anal. Chim. Acta,   2013, 792, pp 110-114

      Abstract: Poly(N-isopropylacrylamide)-co-acrylic   acid (pNIPAm-co-AAc) microgels were painted on the Au electrode   of a quartz crystal microbalance (QCM). Another Au layer   (overlayer) was subsequently deposited on the microgel layer.   This structure is known as a microgel-based etalon. These devices   exhibit optical properties (i.e., color) that depend on soln. pH   and temp., among other things. Previously, the authors measured   QCM frequency shifts that are a result of soln. pH changes; the   frequency shifts are a direct result of the pH dependent   solvation state of the microgels that make up the etalon. In   fact, the shifts obsd. for the etalons were much greater in   magnitude than just a microgel layer immobilized on the QCM   crystal without the Au overlayer. The authors reasoned that the   Au overlayer lead to an enhancement of the obsd. frequency change   due to its mass. In this submission the authors study how the Au   overlayer thickness (mass) affects the obsd. sensitivity to soln.   pH. The change in QCM resonant frequency depended dramatically on   the mass of the Au overlayer. [on SciFinder(R)]

      Address (URL):