Micromechanical cantilever as an ultrasensitive pH microsensor

R. Bashir; J. Z. Hilt; O. Elibol; A. Gupta; N. A. Peppas

doi:10.1063/1.1514825

Micromechanical cantilever as an ultrasensitive pH microsensor

R. Bashir, J. Z. Hilt, O. Elibol, A. Gupta, N. A. Peppas

Research output: Contribution to journal › Article › peer-review

Abstract

We report on a pH sensor with ultrahigh sensitivity based on a microcantilever structure with a lithographically-defined crosslinked copolymeric hydrogel. Silicon-on-insulator wafers were used to fabricate cantilevers on which a polymer consisting of poly(methacrylic acid) (PMAA) with poly(ethylene glycol) dimethacrylate was patterned using free-radical UV polymerization. As the pH around the cantilever was increased above the pK _a of PMAA, the polymer network expanded and resulted in a reversible change in surface stress causing the microcantilever to bend. Excellent mechanical amplification of polymer swelling as a function of pH change within the dynamic range was obtained, with a maximum deflection sensitivity of 1nm/5×10^-5ΔpH.

Original language	English (US)
Pages (from-to)	3091-3093
Number of pages	3
Journal	Applied Physics Letters
Volume	81
Issue number	16
DOIs	https://doi.org/10.1063/1.1514825
State	Published - Oct 14 2002
Externally published	Yes

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Physics and Astronomy (miscellaneous)

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10.1063/1.1514825

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AU - Peppas, N. A.

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Micromechanical cantilever as an ultrasensitive pH microsensor

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