Engineering Proceedings (Nov 2022)
Advanced Quartz Microbalance Sensors for Gas-Phase Applications: Effect of Adsorbate on Shear Bond Stiffness between Physical Transducer and Superlattice of Latex Nanoparticles
Abstract
New sensitive architectures built on soft surface architectures or nano-sized blocks also require a rethinking of the principles of the operation of traditional physical recording methods. Here, we report an experimental study of complex loadings for classical quartz crystal microbalance (QCM) that appear on the surface with flexible spatial organization and variable coupling by which the interface architecture is connected to the transducer. Sensitive layers are superlattices formed on 100 nm LB1 latex nanoparticles self-assembled during the contact line deposition in evaporating sessile droplets with or without nonionic surfactant TWEEN® 20. It was shown that QCM resonance frequency change is not primarily determined by the adsorbate mass alone (as for LB1&TWEEN® 20 mixture), but rather by the link by which interfacial architecture is bound to the transducer (as for LB1 superlattice). A model has been proposed and substantiated in which the manifestation of anti-Sauerbrey behavior is associated with changes under the action of water vapor in the characteristics of the contact area of intra-film 3D mountainous deposits with the transducer surface. The possibility of a gaseous analyte not only to change the loading of QCM but also the features of the mechanical behavior of the mass associated with the surface opens the way to the creation of a new class of highly selective sensors of especially dangerous or critically important analytes. Due to the selective effect of the analyte on the processes of interfacial friction in the contact layer between the sensitive architecture and the sensor substrate, a contrast pattern of response to the target analyte can be formed. This is due not so much to the large magnitude of the response itself, but to the fact that the change in the analytical signal is opposite to the “usual” Sauerbray-like shift of the resonant frequency.
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