Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7148870 | Sensors and Actuators B: Chemical | 2013 | 8 Pages |
Abstract
We demonstrate the methanol detection ability of stimulus-responsive magnetically polarizable nanoemulsions. The oil-in-water type of nanoemulsions of droplet radius â¼100Â nm is produced by emulsification of Fe3O4 based magnetic nanofluid in presence of water, oil and an anionic surfactant. The nano-emulsion droplets in a cylindrical vial or cuvette placed inside a small solenoid that produces a magnetic field of â¼100Â Gauss constitute the sensor assembly. It is observed that the presence of methanol in ppm level produces strong changes in the repulsive forces between the nanoemulsion droplets, giving rise to a red shift in the incident white light and a visually perceptible color change of the nanoemulsion. The origin of the red shift is studied by measuring the subtle changes in the intermolecular forces between the emulsion droplets in presence of methanol molecules. We observe that the diffusion of methanol molecules significantly alters the onset of electrostatic repulsion between nanodroplets. The sensor showed a linear detection range of 0-2250Â ppm and a response time of â¼1Â s. The present approach is a simple, inexpensive and useful for sensitive detection of methanol in aqueous solution.
Related Topics
Physical Sciences and Engineering
Chemistry
Analytical Chemistry
Authors
V. Mahendran, John Philip,