Method and apparatus for characterizing materials by using a mechanical resonator

• US 6,904,786 B2
• Filed: 10/07/2002
• Issued: 06/14/2005
• Est. Priority Date: 10/08/1997
• Status: Expired due to Fees

• Current Assignee: Meas France
• Original Assignee: Symyx Technologies Incorporated (Dassault Systemes SA)
• Inventors: Bennett, James, Matsiev, Leonid, McFarland, Eric
• Primary Examiner(s): Williams, Hezron
• Assistant Examiner(s): MILLER, ROSE MARY
• Application Number:
  US10/266,047
• Publication Number:
  US 20030041653A1
• Time in Patent Office: 981 Days
• Field of Search: 73/240.1, 73 2403- 2406, 73/300.1, 73/300.4, 73/310.1, 73/310.2, 73/310.3, 73/310.5, 73/310.6, 73/32.A, 73/32.R, 73/530.1, 73/540.1, 73/540.2, 73/542.3, 73/544.1, 73/614.5, 73/617.5, 73/617.9, 735/79, 310/360, 310/316, 310/320, 422/68.1, 422/75, 422/98
• US Class Current: 73/24.06
• CPC Class Codes: B01J 2219/00704 integrated with the reactor apparatus
• CPC Class Codes: G01H 13/00 Measuring resonant frequency
• CPC Class Codes: G01N 11/16 by measuring damping effect upon oscillatory body
• CPC Class Codes: G01N 2009/006 vibrating tube, tuning fork
• CPC Class Codes: G01N 2291/014 Resonance or resonant frequency
• CPC Class Codes: G01N 2291/0224 Mixtures of three or more liquids
• CPC Class Codes: G01N 2291/0255 (Bio)chemical reactions, e.g. on biosensors
• CPC Class Codes: G01N 2291/0256 Adsorption, desorption, surface mass change, e.g. on biosensors
• CPC Class Codes: G01N 2291/02818 Density, viscosity
• CPC Class Codes: G01N 2291/0422 Shear waves, transverse waves, horizontally polarised waves
• CPC Class Codes: G01N 2291/0423 Surface waves, e.g. Rayleigh waves, Love waves
• CPC Class Codes: G01N 2291/0427 Flexural waves, plate waves, e.g. Lamb waves, tuning fork, cantilever
• CPC Class Codes: G01N 29/022 Fluid sensors based on microsensors, e.g. quartz crystal-microbalance [QCM], surface acoustic wave [SAW] devices, tuning forks, cantilevers, flexural plate wave [FPW] devices microdevices per se B81B
• CPC Class Codes: G01N 29/036 by measuring frequency or resonance of acoustic waves
• CPC Class Codes: G01N 29/30 Arrangements for calibrating or comparing, e.g. with standard objects
• CPC Class Codes: G01N 29/348 with frequency characteristics, e.g. single frequency signals, chirp signals measuring frequency of mechanical vibrations or acoustic waves in general G01H1/06, G01H3/04; measuring frequency or analysing frequency spectra G01R23/00
• CPC Class Codes: G01N 29/42 by frequency filtering or by tuning to resonant frequency
• CPC Class Codes: G01N 29/4418 with a model, e.g. best-fit, regression analysis
• CPC Class Codes: G01N 29/4427 with stored values, e.g. threshold values
• CPC Class Codes: G01N 29/4436 with a reference signal amplitude comparison G01N29/48
• CPC Class Codes: G01N 9/002 : using variation of the resonant frequency of an element vibrating in contact with the material submitted to analysis G01N9/34 takes precedence
• CPC Class Codes: G01N 9/34 : by using elements moving through the fluid, e.g. vane
• CPC Class Codes: G10K 11/02 : Mechanical acoustic impedances; Impedance matching, e.g. by horns; Acoustic resonators

Abstract

A method and apparatus for measuring properties of a liquid composition includes a mechanical resonator, such as a cantilever, connected to a measurement circuit. The mechanical resonator'"'"'s response over the frequency range depends on various characteristics of the liquid being tested, such as the temperature, viscosity, and other physical properties. The invention is particularly suitable for combinatorial chemistry applications, which require rapid analysis of chemical properties for screening.

Claims

1. A method for the determination of viscosity of a fluid comprising:

a) providing at least one cantilever;

b) vibrating said at least one cantilever;

c) calibrating said at least one cantilever by observing decaying free oscillations of said at least one cantilever when said vibratory means is terminated using a vacuum or a known fluid as a standard;

d) measuring the decay in free oscillations of the at least one cantilever in an unknown fluid; and

e) calculating the viscosity of the unknown fluid by reference to the standard.

2. A method according to claim 1 wherein the fluid is a gas.

3. A method according to claim 2 wherein the gas is a mixture of gasses.

4. A method according to claim 1 wherein the fluid is a liquid.

5. A method according to claim 4 wherein the liquid is a neat liquid.

6. A method according to claim 4 wherein the liquid is a mixture.

7. A method according to claim 1 wherein said at least one cantilever comprises a piezoelectric crystal.

8. A method according to claim 1 wherein the at least one cantilever is in an array of resonators.

9. A method according to claim 8 wherein said array is selected from the group consisting of one-dimensional and two-dimensional arrays.

10. A method according to claim 8 wherein said array of cantilevers is used to determine variations of responses of a fluid.

11. A method according to claim 10 wherein the fluid is a flowing fluid.

12. The method of claim 1, wherein the cantilever is a coated cantilever.

13. The method of claim 12, wherein the coated cantilever comprises a corrosion resistant coating.

14. The method of claim 12, wherein the coated cantilever comprises a functionality coating.

15. A method for the determination of the completeness of a chemical reaction or process comprising observing the change in the viscosity of solution or mixture using the method according to:

a) providing at least one cantilever;

b) vibrating said at least one cantilever;

c) calibrating said at least one cantilever by observing decaying free oscillations of said at least one cantilever when said vibrating is terminated using a vacuum or a known fluid as a standard;

d) measuring the decay in free oscillations of the at least one cantilever in an unknown fluid; and

e) calculating the viscosity of the unknown fluid by reference to the standard.

16. A method for determining the presence of inhomogenieties and gradients in a flowing fluid comprising observing the viscosity or density using a method according to:

a) providing at least one cantilever;

b) vibrating said at least one cantilever;

c) calibrating said at least one cantilever by observing decaying free oscillations of said at least one cantilever when said vibrating is terminated using a vacuum or a known fluid as a standard;

d) measuring the decay in free oscillations of the at least one cantilever in an unknown fluid; and

e) calculating the viscosity of the unknown fluid by reference to the standard.