Ultrasensitive quartz crystal microbalance enabled by micropillar structure

We report a method to significantly enhance the mass sensitivity of a quartz crystal microbalance (QCM) device in which Polymethyl Methacrylate (PMMA) micropillars were fabricated on QCM surface to form a two-degrees-of-freedom vibration system. PMMA micropillars were fabricated using nanoimprinting lithography technology. The QCM-micropillar coupled system exhibits a unique resonant frequency, near which the mass sensitivity of QCM can be enhanced by several orders of magnitude. Both numerical simulation and theoretical analysis were conducted to understand this improvement. Thereafter, ultrahigh sensitivity of the QCM-micropillar system was demonstrated by detecting a 1H, 1H, 2H, 2H-perfluorooctyl-trichlorosilane single monolayer film. (C) 2014 AIP Publishing LLC.