Molecular recognition induced mechanics: isotope effects in the interaction between gas phase substances and polymer-coated microcantilevers

Abstract

A novel Porous-Silicon-Over-Silicon (PSOS) chemomechanical microcantilever sensor for the isotope discrimination of gas phase substances is presented. A strong isotope effect is observed in the guest induced PSOS microcantilever bending curves of novel poly-4vinylpyridine (P4VP) coated microcantilevers. Isotopologues of ethanol and water exhibit a clear difference in their time dependent bending response patterns. While the sorption of protiated isotopologues exhibits Langmuir-type sorption curves, deuterated isotopologues exhibit anomalous bending overshoot curves.

Scanning electron microscopic assessment of coating irregularities and their precursors in unexpanded durable polymer‐based drug‐eluting stents

“…Next, the model was applied to the description of the time‐dependent bending curves in the case of absorption of ethanol, CH 3 CH 2 OH, and its two isotopologues, CH 3 CH 2 OD and CD 3 CD 2 OD, to the same microcantilever system and under the same experimental conditions. Finally, the model was applied to the description of the effect of the flow of the carrier gas on the time‐dependent bending curves for the case of the fully deuterated ethanol isotopologue, CD 3 CD 2 OD 21, 22…”

“…Commercial microcantilever arrays (Octensis, Micromotive GmbH, Mainz, Germany) were asymmetrized prior to polymer coating. The asymmetrization process included deposition of a 50 nm gold protective mask atop one of the microcantilever faces followed by fabrication of a porous silicon layer on the opposite face using reaction induced vapor phase stain etching,21, 22 Figure 1. The microcantilever arrays were mounted on a holder above a vessel containing 40 mL of HNO 3 (65%) and 10 mL of HF (49%).…”

“…Recently, we published the kinetic isotope effect in the guest‐induced microcantilever bending, showing that under the same conditions deuterated guest species yield large bending overshoots while their protiated analogues do not show any significant overshoots 21, 22. We proposed a four‐state phenomenological model to account for the observations.…”

Simple physical model for chemomechanics

“…The asymmetrization process included deposition of a 50 nm gold protective mask atop one of the microcantilever faces followed by fabrication of a porous silicon layer on the opposite face using reaction induced vapor phase stain etching, 21,22 Figure 1. The microcantilever arrays were mounted on a holder above a vessel containing 40 mL of HNO 3 (65%) and 10 mL of HF (49%).…”

“…21,22 We proposed a four-state phenomenological model to account for the observations. Different models attempts to link the chemical process taking place between guest molecules and organic layers harnessed to microcantilevers with the resulting macroscopic mechanical microcantilever deformation.…”