Accession Number:

ADA234129

Title:

Flexural Plate Wave Devices for Chemical Analysis

Descriptive Note:

Memorandum rept.

Corporate Author:

NAVAL RESEARCH LAB WASHINGTON DC

Report Date:

1991-04-16

Pagination or Media Count:

50.0

Abstract:

The mass-sensitivities, vapor sensitivities, and vapor detection limits of flexural plate wave FPW and surface acoustic wave SAW vapor sensors are compared both theoretically and experimentally. FPW devices offer high mass sensitivity at much lower operating frequency. Mass sensitivity increases as membranes thickness decreases frequency decreases at the same time. This scaling law is in contrast to SAW devices where mass sensitivity increases as frequency increases. FPW devices with sorbent polymer films respond to vapors in a manner similar to SAW devices coated with the same polymer. The FPW vapor sensor, however, offers lower absolute noise levels and hence lower vapor detection limits. It is also demonstrated experimentally that FPW devices can monitor changes in polymer films as the polymer undergoes the glass transition. Plots of frequency vs. temperature show a discontinuity in slope at the static glass transition.

Subject Categories:

  • Physical Chemistry

Distribution Statement:

APPROVED FOR PUBLIC RELEASE